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April 7, 2006
Port Multiplier PCIe SATA II Host Adapter
A Review of the Sonnet Tempo SATA E4P Four Port External PCI Express Host Adapter
By Arthur Whalem
Sonnet Technologies is shipping the Tempo SATA E4P ($299.95) four port external serial ATA PCI Express host adapter for PowerMac Dual-Core and Quad models with an available PCIe slot. The Sonnet Tempo SATA E4P provides a native PCI Express (PCIe) 4x host bus interface with FIS-based port multiplier capability. When using up to four, five bay port multiplier enclosures the E4P can mount up to twenty SATA hard drives. The E4P is SATA II compliant and supports auto-negotiation with both 1.5Gb/s and 3Gb/s hard drives. Four external eSATA ports are available for hard drive connections. The E4P includes Spread Spectrum Clocking (SSC) compatibility, hot swap capability and supports sleep mode with a PowerMac G5 computer. The Tempo SATA E4P package includes the PCIe SATA host adapter, a quick start guide and an addendum. With this card installed, your PowerMac G5 Dual-Core or Quad has four external eSATA ports ready for direct cable or port multiplier connections with your hard drives.
System Requirements
Mac OS X Version 10.2 and later.
Windows XP support.
Supports up to four external SATA 3.5" drives using direct cable method.
Supports up to twenty external hard drives using four, five bay PM enclosures.
Sonnet has two PCIe SATA host adapter models available. They include the port multiplier compatible Tempo SATA E4P ($299.95) which is the subject of this review. It has four external eSATA ports. The other option is the Tempo SATA E4i ($199.95) which has four internal SATA type "L" connectors. The E4i does not support port multiplication or booting but it does support sleep mode and features hot swap capability. The other new port multiplier option from Sonnet is the Tempo SATA X4P ($299.95). It provides four external eSATA ports for any PowerMac with an open PCI or PCI-X slot. The X4P supports sleep mode, host swap, port multiplier and single cable per drive connections (direct connections). It does not have boot capability. All of these new Sonnet cards use the same 2.0 version firmware.
Which PCIe Slot Works Best?PCI Express also known as PCIe, communicates using 250MB per second data lanes. PCI Express slot and card bandwidth is determined by the number of data lanes they can accommodate. One lane, four lanes, eight lanes, or 16 lanes are some of the typical PCIe options available. The PowerMac G5 Dual-Core and Quad-Core models have four PCI Express slots. PCI Express slot 1 which is the bottom slot has 16 lanes. It is designated as "1" 16x on the PowerMac G5 PCIe frame. This16x PCIe slot is the fastest slot in the PowerMac G5. It is factory configured for use with the Apple pre-installed video card. Slots 2 and 4 are empty when your new PowerMac G5 arrives. They both provide 4x speed. At 250 MBps per lane, a four-lane (4x) slot can transfer data at up to 1GB per second which should be similar in speed to a 64-bit 133MHz PCI-X slot which has a theoretical maximum speed of 1067 MB per second. The Apple PowerMac G5 PCIe bus slot 3 is rated at a speed of 8x. At 250 MBps per lane, an eight-lane (8x) slot can transfer data at up to 2GB per second. That is almost twice as fast as a 64-bit 133MHz PCI-X slot.
According to page 12 of the Apple PowerMac G5 Technology Overview, "Each slot uses a standard connector that can accommodate a card of any size. This means a four-lane card works perfectly in an eight-lane slot. If the card has more lanes than the slot, the card adjusts to the bandwidth available and “downshifts” to that data rate. With the high-bandwidth architecture in the new Power Mac G5, your system will not only achieve faster performance today, but will be ready for future technologies as well. For example, 10-gigabit networking technology, which can achieve up to 2.5 GBps of data throughput, will require an eight-lane slot."
Sonnet has a FAQ on-line, that recommends that you do not use the Sonnet PCIe SATA host adapters including the Tempo SATA E4P in a 8x or 16x slot. It states, "Q. Can I operate a Sonnet PCIe x4 card in a PCIe x8 or x16 slot? A. Not at this time." While I have found that mounting a RAID with the Tempo SATA E4P in the 8x PCIe slot 3 may work, it will occasionally not be recognized when booting. I tested the Tempo SATA E4P in slot 3 as the Apple Technology Overview indicated it should work.
In three out of twenty tests of rebooting a PowerMac G5 Quad with the Tempo SATA E4P installed in slot 3, the card was not recognized by the Macintosh. When this situation occurs you can open system profiler and the E4P card will not show up under the PCI cards tab. Restarting the computer usually enabled the Tempo SATA E4P in system profiler. Every reboot with a Tempo SATA E4P in slot 3 is one more chance that it will not be recognized. There appears to be a hardware problem with the Tempo SATA E4P that does not allow it to work consistently while installed in an 8x slot.
During these tests, there was no benefit to using the 4x PCIe Tempo SATA E4P card in slot 3. I found the Sonnet Tempo SATA 4EP usually runs at the same speed whether it is in a 4x or an 8x PCIe slot. The problem is that the E4P will not operate reliably in slot 3. As this is the case, users may be limited to using a maximum of two Tempo SATA E4P cards in a PowerMac G5. I would have to agree with Sonnet that the Tempo SATA E4P is not compatible with slot 3. However, when using the Tempo SATA E4P in slot 2 or slot 4 it works very well. Both of these slots are four-lane (4x) which matches the speed of the Tempo SATA E4P PCIe host adapter.
Features
The Sonnet Tempo SATA E4P is the first shipping four port external native PCI Express (PCIe) 4x SATA host adapter for PowerMac G5 Dual-Core models, which were released Oct. 19, 2005. Until recently, there was only one Macintosh PCIe SATA solution, which was the Highpoint RocketRAID. It uses a bridge board instead of a native PCIe interface. The Tempo SATA E4P allows the user to use Disk Utility to setup individual drives or a RAID, supports sleep mode, hot swap, passes SATA hard drive temperature data and is compatible with port multiplier enclosures. Many of these features are not available with the Highpoint solution.
No Boot Capability
The Sonnet Tempo SATA E4P does not have boot capability. FirmTek SATA host adapters provide this feature for PowerMac models with PCI or PCI-X slots. However, no company has released a PCI Express SATA host adapter for the Macintosh that supports booting so far.
Connection Light Feedback
The Sonnet Tempo SATA E4P provides status LED lights that can be seen through the clear plastic PowerMac G5 side panel. The lights are located on the top of the Sonnet card toward the rear of the PowerMac G5. When a green light is on the hard drives are powered and ready for use. When an amber light is flashing the SATA hard drives are reading/writing data. Monitoring these lights can be helpful if you are having trouble mounting a RAID or an individual SATA hard drive on the desktop. Channel 1 is farthest from the back of the PowerMac G5 and channel 4 is near the eSATA connection ports. You can also see these channel designations listed in Disk Utility in the connection ID information of your hard drives.
Controller Details
According to the Kill-a-Watt electricity usage monitor, the Tempo SATA E4P requires approximately four watts to operate when installed in a PowerMac G5. The E4P utilizes the Marvell 88SX7042 PCIe to Serial ATA Controller chip. It provides a dedicated channel for each SATA port, supports hot-plug SATA drives and is compliant with both SATA 1.0 and SATA II including Native Command Queuing (NCQ). The Marvell 88SX7042 controller chip supports SATA PM, direct SATA connections and Spread Spectrum Clocking (SSC). Tempo SATA E4P users will not need to be concerned whether their hard drives have SSC turned on or off as the card supports both configurations. In addition, the Sonnet port multiplier works properly with a five drive SATA port multiplier enclosure or with individual hard drive
connections. The Sonnet Tempo SATA E4P was able to handle any configuration of SATA I, SATA II, and Spread Spectrum Clocking (SSC) that I was able to test. I could not find a single hard drive that would not work with the Tempo SATA E4P. This is a nice feature that many of my Macintosh SATA controllers do not share. However, if you have a SATA PM enclosure with an older Silicon Image 3726 port multiplier chip installed, you may find that it will not work with the Sonnet Tempo SATA E4P until the firmware has been upgraded to version 1.0114 or later. This only applies to port multiplier enclosures. You can determine if you have the old 3726 firmware by searching the Mac OS X system log for the word "Port Multiplier". The old firmware will display Port Multiplier 0x1095 0x4726 0x00 0x06 0x06 in the log file. The key to finding the old firmware revision is 0x00 in the third number. Sonnet is shipping an addendum with each Tempo SATA E4P card explaining the situation. You will find that if you have the old firmware,
the Sonnet Tempo SATA E4P host adapter will not mount any drives in the enclosure. Most enclosure vendors now have the proper firmware update available to correct this issue. If you contact your enclosure vendor they should be able to help you complete the firmware upgrade.Firmware On-line
You can also upgrade the Sil 3726 firmware yourself by downloading the new firmware from the Silicon image web site. It requires a PC to upgrade the firmware, using the command prompt. I was able to upgrade several PM enclosures using the command: "3726FWDownload -w -d1 3726_1.0114.bin". The port multiplier needs to be connected to an on board SATA port on the PC with at least one drive in the enclosure for version 1.3 of the installer to work. Your setup may require a different command for the drive (-d1, -d2 and so on). Once the new Sil 3726 firmware is installed the port multiplier will display "Port Multiplier 0x1095 0x3726 0x17 0x06 0x06" in the Mac OS X system log and hard drives installed in the enclosure will mount with the Sonnet Tempo SATA E4P. If you obtain a PM enclosure with the old Sil 3726 firmware these instructions should help get you started.
Enclosures
As the Tempo SATA E4P host adapter is an external eSATA solution you will need an enclosure for your SATA hard drives. AMUG has tested several external SATA hard drive enclosures that work well with the Tempo SATA E4P host adapter. The ability of the E4P to work with both port multiplier and direct SATA connections makes it compatible with a wide variety of enclosure options. Direct connection drive enclosures provide more speed than a PM enclosure when used with the same number of hard drives. However, a five bay PM enclosure only requires one port on the Tempo SATA E4P and supports up to five SATA hard drives. Four individually connected SATA hard drives will use up all four ports on the Tempo SATA E4P host adapter. To get to a level of supporting eight directly connected SATA hard drives you will need two Tempo SATA E4P cards. However, when using two PM enclosures a single Tempo SATA E4P host adapter can support up to ten SATA hard drives and still have two ports left. A table of some of my favorite direct connection drive enclosures and several port multiplier enclosure solutions are provided below.
Direct Connection Drive Enclosures
| Dual Disk Array 3SA | TrayDock eSATA | SeriTek/2EN4 | SeriTek/2EN2 |
 |
 |
 |
 |
| 6 Bay eSATA | 4 Bay eSATA | 4 Bay eSATA | 2 Bay eSATA |
| The six bay Addonics Dual 3SA is created by using two Disk Array 3SA cages mounted inside of a Storage Tower. | The WiebeTech TrayDock eSATA is a four bay enclosure which requires no assembly other than adding SATA hard drives. | The FirmTek SeriTek/2EN4 is a four bay enclosure which requires no assembly other than adding SATA hard drives. | The FirmTek SeriTek/2EN2 is a two bay enclosure which requires no assembly other than adding SATA hard drives. |
| Hot Swap Supported | Hot Swap Supported | Hot Swap Supported | Hot Swap Supported |
| Backplane mounting. Uses 11" SATA cable to connect each drive to rear eSATA ports. | Backplane mounting. Uses 6" SATA cable to connect each drive to rear eSATA ports. | Direct Backplane mounting. No additional cable is required to connect drives to rear eSATA ports. | Direct Backplane mounting. No additional cable is required to connect drives to rear eSATA ports. |
| Six eSATA ports | Four eSATA ports | Four eSATA ports | Two eSATA ports |
| 105-118 degrees | 93-101 degrees | 116-127 degrees | Varies, 3 speed fan |
| Supports Sleep Mode | Supports Sleep Mode | Supports Sleep Mode | Supports Sleep Mode |
| Quieter than PowerMac | Louder than PowerMac | Very Quiet | Quiet to Very Quiet |
| Advantage: 6 bays in a single enclosure, can add a quiet fan upgrade, easy to modify rear jacks or drive cages. Drive trays protect hard drives, are easy to mount drives in and dissipate heat well. Temperature alarm. | Advantage: Keeps your SATA hard drives cooler than any other SATA four bay enclosure AMUG has tested. Drive trays protect the bottom of hard drives and are easy to mount drives in. | Advantage: This is the quietest four bay enclosure that AMUG has tested. Unit is a solid industrial design that is very well built. Provides activity and power lights along with a Temperature alarm. | Advantage: This is a quiet two bay enclosure that provides a 3 way user selectable switch to select a fan speed that meets your needs. Provides activity and power lights. |
| Cons: Is not quiet with standard fan configuration. Requires assembly. No hard drive activity lights. | Cons: Is not quiet. No hard drive activity lights. No easy way to modify power supply fan noise. | Cons: While hard drives operate within the manufacturers specifications, hard drives ran the warmest in this enclosure. | Cons: Requires two of these enclosures to use all four ports on the host adapter. External power supply required. |
| $449 | $449.95 | $499.95 | $199.95 |
The new SATA port multiplier standard also known as "SATA PM" is also supported by the Sonnet Tempo E4P. This allows up to five hard drives to be connected using a single eSATA cable. A port multiplier enclosure with five drives installed in it is limited to write speeds of about 200MB/second and read speeds of about 250MB/second when using the Tempo SATA E4P. Even though the port multiplier has bandwidth limitations, users may find that a five drive PM enclosure can out perform a four drive direct connection striped RAID set once the volume is 50% full or more. While a PM enclosure may not perform as fast when empty as a direct connection drive setup, it will usually provide more stability in performance a the hard drives becomes full.
Port Multiplier Enclosures
| SilverSATA V | Dual 3SA + 5x1 | CSE-M35T + 5x1 | Fusion 500P |
 |
|
 |
 |
| 5 Bay eSATA | 6 Bay eSATA | 5 Bay eSATA | 5 Bay eSATA |
| The WiebeTech SilverSATA V port multiplier enclosure is a five bay SATA enclosure with a single eSATA PM connection on the rear. | Includes an Addonics ST5X1PM ($209) and two 3SA cages ($180) to create a 5 bay eSATA PM enclosure plus an extra SATA Bay. Two 80mm fans added ($20). | Includes an Addonics ST5X1PM ($209) and the SuperMicro CSE-M35T ($115) to create a 5 bay eSATA PM enclosure. One 92mm and two 80mm Nexus Real Silent fans ($30). | The Sonnet Fusion 500P is a five bay SATA enclosure with a single eSATA PM connection on the rear. |
| Hot Swap Supported | Hot Swap Supported | Hot Swap Supported | Hot Swap Supported |
| Direct backplane mounting. Uses 5" SATA cable to connect port multiplier to rear eSATA port. | Backplane mounting. Uses 11" SATA cable to connect each drive to port multiplier. | Backplane mounting. Uses 11" SATA cable to connect each drive to port multiplier. | Backplane mounting. Uses SATA cable to connect each drive to port multiplier. |
| One PM eSATA port | PM eSATA port plus 1 | One PM eSATA port | One PM eSATA port |
| 93-100 degrees | 105-118 degrees | 107-111.2 degrees | 114.8 - 120.2 degrees |
| Supports Sleep Mode | Supports Sleep Mode | Supports Sleep Mode | Supports Sleep Mode |
| Louder than PowerMac | Quieter than PowerMac | Quieter than PowerMac | Quieter than PowerMac |
| Advantage: 5 bays in a single enclosure. Temperature alarm. Keeps hard drives very cool. Drive activity and power lights. Sturdy design. No assembly required other than installing hard drives. | Advantage: 6 bays in a single enclosure. Can add a quiet fan upgrade. Drive trays protect hard drives and are easy to mount drives in. Temperature alarm. Can be used in a single cable per drive configuration by using a different rear panel cover. | Advantage: This is a quiet five bay PM enclosure when using three Nexus silent fans. Provides temperature alarm. Can be used in a single cable per drive configuration by using a different rear panel cover. | Advantage: This is a quiet five bay PM enclosure. Provides drive activity lights and user configurable fan. Small foot print. Sturdy design. No assembly required other than installing hard drives. |
| Cons: Is not quiet. No easy way to modify power supply fan noise. Expensive. | Cons: Is not quiet with standard fan configuration. Requires assembly. No hard drive activity lights. | Cons: Not quiet with standard fan config. Requires assembly. No hard drive activity lights. | Cons: Inserting trays into the enclosure may seem stiff in some bays. |
| $999.95 | $429 = ST5X1PM and two 3SA, fans & eSATA cable. | $374 = ST5X1PM and CSE-M35T, fans & eSATA cable. | $499.95 |
RAID PerformanceA Sonnet Tempo SATA E4P host adapter using firmware version 2.0 was installed in slot 4 of a PowerMac G5 2.5GHz Quad, running Mac OS X 10.4.5. A WiebeTech SilverSATA V five bay port multiplier enclosure was used with the E4P for the PM tests. An Addonics Dual 3SA Storage Tower was used for the direct connection tests. DiskTester 10GB read and write tests were performed using a run area test so that this article could display how the RAID performs with the E4P. DiskTester is a Terminal application that measures the combined performance of a volume and the Mac OS X operating system. Using the command: ./disktester run-area-test --transfer-size 131072 --test-size 10240 --delta-percent 10 DriveName, puts DiskTester to work testing how the RAID will perform when empty, 10% full 20% full and so on. The table below displays how different five drive striped RAID sets perform when using a single port on the Tempo SATA E4P with a port multiplier enclosure.
E4P Port Multiplier 5 Drive Striped RAID - DiskTester 10GB Test
| Maxline 300 7L300S0 | Maxline 300 7V300F0 | Hitachi 160 HDT722516DLA380 | Seagate 160GB ST3160812AS |
| Area Full | write | read | write | read | write | read | write | read |
| empty | 196.8 | 251.6 | 183.7 | 245.9 | 191.0 | 245.2 | 199.5 | 236.0 |
| 10% | 196.9 | 252.5 | 183.3 | 245.3 | 192.5 | 245.1 | 200.7 | 238.6 |
| 20% | 195.9 | 251.2 | 184.5 | 245.4 | 191.5 | 245 | 200.8 | 240.1 |
| 30% | 196.3 | 251.0 | 184.0 | 245.5 | 191.0 | 243.5 | 200.7 | 239.5 |
| 40% | 195.6 | 251.4 | 182.9 | 245.6 | 190.7 | 244.8 | 200.8 | 239.6 |
| 50% | 196.3 | 248.3 | 183.0 | 245.8 | 190.5 | 244.4 | 200.6 | 237.7 |
| 60% | 195.5 | 239.8 | 183.6 | 245.9 | 189.6 | 243.9 | 200.8 | 236.6 |
| 70% | 195.4 | 231.8 | 182.6 | 246.1 | 189.7 | 222.5 | 200.8 | 236.3 |
| 80% | 194.9 | 207.8 | 182.3 | 246.7 | 187.7 | 200.5 | 198.5 | 229.9 |
| 90% | 189.3 | 177.5 | 181.9 | 221.9 | 168.8 | 177.5 | 199.8 | 203.6 |
| Average | 195.3 | 236.3 | 183.2 | 243.4 | 188.3 | 231.2 | 200.3 | 233.8 |
used with a PowerMac G5 2.5 GHz Quad in PCIe slot 4 with a five drive PM setup.
The next table below shows how a four drive striped RAID set performs when using the direct connection method with the Sonnet Tempo SATA E4P host adapter. This method utilizes all four ports on the Tempo E4P.
E4P Direct Connect 4 Drive Striped RAID - DiskTester 10GB Test
| Maxline 300 7L300S0 | Maxline 300 7V300F0 | Hitachi 160 HDT722516DLA380 | Seagate 160GB ST3160812AS |
| Area Full | write | read | write | read | write | read | write | read |
| empty | 250.1 | 244.3 | 276.3 | 277.3 | 195.8 | 241.3 | 275.5 | 285.1 |
| 10% | 241.7 | 240 | 268.3 | 269.4 | 219.2 | 234.5 | 277.6 | 281.5 |
| 20% | 237.9 | 235.5 | 261.5 | 261.8 | 219.6 | 227.1 | 270.4 | 274.2 |
| 30% | 230.4 | 231 | 252.7 | 253.9 | 186.4 | 219.1 | 261.8 | 266.0 |
| 40% | 218.7 | 219 | 248.1 | 249.5 | 198 | 213.8 | 254.4 | 255.8 |
| 50% | 211 | 211.9 | 232.5 | 234.3 | 187.6 | 203.4 | 241.2 | 243.7 |
| 60% | 195.5 | 196.6 | 225.1 | 226.2 | 156.6 | 195.6 | 227.7 | 230.1 |
| 70% | 188.5 | 189.9 | 207.9 | 209.1 | 156 | 177.2 | 210.1 | 211.2 |
| 80% | 170.5 | 171.6 | 198.4 | 200 | 146 | 160.5 | 191.3 | 192.5 |
| 90% | 149.6 | 152.2 | 177.2 | 178.2 | 138.2 | 142.2 | 167.7 | 168.9 |
| Average | 209.39 | 209.2 | 234.8 | 236 | 180.34 | 201.47 | 237.8 | 240.1 |
used with a PowerMac G5 2.5 GHz Quad in PCIe slot 4 with a four drive direct connect setup.
In the direct connection four drive test the Seagate 160GB 7200.9 model slightly out performed the Maxtor Maxline 300GB 7V300F0 SATA II model, but not by much. Don't expect the Seagate 160GB 7200.9 results shown here to also apply to the larger Seagate 7200.9 models. Tests have shown that each model of hard drive can have its own characteristics. By comparing the two charts above, you can see that the PCIe Sonnet Tempo E4P with a port multiplier enclosure limits the write performance of a five drive striped RAID set to about 200MB per second. As the charts demonstrate, different hard drive combinations will provide different performance characteristics. Some drives will of course perform slower than 200MB per second based on how well their firmware works with the Sil 3726. With that said, five hard drives in a PM enclosure can provide better performance as the RAID becomes full. Certain drives perform better with a PM system than others and it is not necessarily the same drives that perform well with the standard direct connection drive method.
As an example, the Maxline 7V300F0 SATA II drive easily beats the Maxline 7L300S0 SATA I hard drive with a standard direct connection setup. However, when the older Maxline SATA I drive is mounted in a PM enclosure with the E4P, it provides faster write speeds than the Maxline 7V300F0. I believe this performance oddity has to do with the Sil 3726 port multiplier chip. The Maxtor 7V300F0 firmware does not seem to be optimized to work efficiently with the Sil 3726 PM chip. SATA hard drives that work well with the Silicon Image Sil 3726 implementation will usually have a performance advantage over those that do not.
8 Drive Direct Connections VS 2 PM Enclosures?
The next question I wanted to answer was how would the performance of eight drives in a striped RAID using two Sonnet PCIe cards with direct connections, compare to using two five bay PM enclosures and ten drives. In this test, Two Sonnet PCIe host adapters were used with a PowerMac G5 Dual 2.0 (Oct. 2005) in PCIe slot 4/2 with eight Seagate 160GB SATA 7200.9 hard drives for this direct connection eight drive striped RAID test. A single Tempo E4P card was used in slot 2 with ten Seagate 160GB SATA 7200.9 hard drives mounted in two 5 bay port multiplier enclosures for the PM striped RAID test. The performance results are displayed below.
Seagate 8 Drive Direct Connection vs 10 Drive Port Multiplier
|
Seagate 160 Direct
|
ST3160812AS Connect |
Seagate 160 Port
|
ST3160812AS Multiplier | |
| Area Full | write | read | write | read |
| empty | 534.5 | 563.0 | 388.3 | 428.8 |
| 10% | 534.3 | 549.0 | 393.6 | 431.6 |
| 20% | 526.9 | 533.0 | 393.5 | 433.0 |
| 30% | 515.9 | 528.4 | 393.9 | 432.7 |
| 40% | 493.4 | 504.6 | 392.8 | 436.6 |
| 50% | 469.1 | 476.4 | 393.6 | 438.4 |
| 60% | 445.7 | 453.8 | 393.8 | 437.9 |
| 70% | 409.5 | 411.2 | 394.0 | 439.6 |
| 80% | 380.0 | 386.5 | 394.3 | 434.8 |
| 90% | 338.1 | 340.4 | 385.3 | 388.4 |
| Average | 464.7 | 474.6 | 392.3 | 430.2 |
The results above demonstrate that the direct connection setup in this test was faster with fewer drives, up until the RAID was 80% full. At that point, the port multiplier enclosures were faster. You can see the RAID write performance curve in the graph below. While the PM speed is steady the direct connection setup gets slower as the RAID becomes full.
It seems to me that write speeds of 390MB per second and read speeds of 430MB per second are fast enough for any computing need I can think of. With the PM setup, only one Sonnet Tempo E4P card is required. However, you will probably want ten hard drives to fill the PM enclosures. Choosing between direct connections and using a port multiplier will probably boil down to individual preferences and what enclosures you may already have available.
Comparing Port Multiplier Setups
When you create a RAID with just a few drives in several port multiplier enclosures you start to notice that the performance is similar to a direct connection drive setup. When three or less drives are used in a PM enclosure, bandwidth limitations are considerably reduced. Several PM setups were tested using up to twenty Seagate 160GB 7200.9 SATA hard drives to see how different RAID setups might perform.
In the graph below you can see the results. The maximum performance from a 16-20 drive four enclosure striped RAID using a single Sonnet Tempo E4P card was almost 700 MB/second. Read performance was a little higher than that. When using only three drives in four PM enclosures for a total of 12 drives, the performance was almost as high as a twenty drive RAID for the first 50% of the RAID capacity. In each case using three or fewer drives in each enclosure provided results that were similar to the direct connection method.
PCIe vs PCI-X
As Sonnet sells a PCI-X version of its four port external PM compatible host adapter, I wondered if there were any performance differences between PCIe and PCI-X. The PCIe version of the card is the Sonnet Tempo SATA E4P and the PCI-X version is the Sonnet Tempo SATA X4P. Both cards use the same firmware. Since Apple abandoned the PCI-X slot with the introduction of the PowerMac G5 "Oct 2005" models, I wanted to see if the PCIe version was faster.
In this test, a Tempo SATA E4P PCIe card was installed in slot 4 of a PowerMac G5 2.5GHz Quad. A Tempo SATA X4P was installed in slot 4 of the original PowerMac G5 2.0 Dual. DiskTester was used with the same five drive PM enclosure which has Sil 3726 firmware version 1.0114 installed. Five Maxtor Maxline SATA I model 7L300S0 hard drives were used in this test.
Maxline 5 Drive Port Multiplier Using PCIe vs PCI-X
|
Maxline 300 PCIe
|
7L300S0 Tempo E4P |
Maxline 300 PCI-X
|
7L300S0 Tempo X4P |
|
| Area Full | write | read | write | read |
| empty | 196.8 | 251.6 | 224.1 | 252.1 |
| 10% | 196.9 | 252.5 | 223.3 | 252.3 |
| 20% | 195.9 | 251.2 | 223.2 | 251.6 |
| 30% | 196.3 | 251.0 | 222.8 | 250.2 |
| 40% | 195.6 | 251.4 | 222.9 | 249.9 |
| 50% | 196.3 | 248.3 | 223.0 | 248.5 |
| 60% | 195.5 | 239.8 | 222.4 | 238.0 |
| 70% | 195.4 | 231.8 | 222.3 | 228.8 |
| 80% | 194.9 | 207.8 | 213.8 | 203.8 |
| 90% | 189.3 | 177.5 | 188.7 | 174.9 |
| Average | 195.3 | 236.3 | 218.6 | 235 |
These tests were run several times as I wondered if the results were correct. Each time you run any disk testing program the results will be a little different. However, in this test the PCI-X Sonnet X4P was able to substantially beat the PCIe Sonnet E4P write speeds in every test completed with a PM enclosure. When you are using a striped RAID for HD video editing the difference between 196MB/sec. write speeds and 224MB/sec. can be important. It seems odd that a port multiplier enclosure with a PCI-X Sonnet Tempo X4P inside the original PowerMac G5 2.0 Dual provides better write speeds than when using a PowerMac G5 2.5GHz Quad with a Sonnet Tempo SATA E4P.
The Silicon Image 3726 press release states, "With the SiI 3726/SiI 3124 combination, Silicon Image has demonstrated read and write performance over a single SATA link in excess of 230MB/s, far exceeding the single link performance of other SATA port multiplier solutions". The only 3124 host adapter I have seen is a PCI-X card and it does provide nice performance. I wonder if Silicon Image has tested the Sil 3726 port multiplier with a PCIe implementation?
I also performed direct connection tests comparing the PCI-X and the PCIe cards but found that in that setup the two RAIDs performed very similar. Based on these tests, port multiplier write speeds were over 10% faster on the PCI-X PowerMac G5 Dual 2.0 with the Tempo X4P, while direct connections compared very closely. Until another PCIe PM SATA host adapter for the Quad is available to compare, it is hard to know if this is an Apple PCIe bus issue, a Sil 3726 issue or a driver related problem. It is also interesting to note, that the Quad provides little or no improved RAID performance over the original PowerMac G5 2.0GHz Dual when using the Sonnet Tempo E4P or the X4P SATA host adapters. It is disappointing that the PCIe bus of the new PowerMac G5 cannot provide an opportunity for significantly faster SATA host adapter performance.
DiscussionI was looking for a SATA host adapter that works with Disk Utility to create RAID sets. I also wanted the card to work in a new PCIe Quad PowerMac G5. It needed to support sleep, direct drive connections and be compatible with port multipliers. The Sonnet Tempo SATA E4P does all of these things. The only features that I would still like to have are boot capability and five drive port multiplier PCIe write speeds of 220MB/sec. The Sonnet PCIe 4x host adapters are easy to install and work very well. If your port multiplier enclosure has the old Silicon Image Sil 3726 firmware, you will need to upgrade the firmware. I upgraded a SilverSATA V and an Addonics Storage Tower with a 5X1 port multiplier installed (ST5X1PM). After the upgrade both devices were recognized by the Tempo E4P and the hard drives were running smoothly on the PowerMac G5. The beauty of the Sonnet Tempo SATA E4P is that it allows you to use your existing direct connection enclosures while also providing you with the ability to try the new port multiplier SATA standard. Sonnet provides great user support and in my opinion the Sonnet Tempo SATA E4P is the best SATA host adapter currently shipping for the new PCIe PowerMac G5 models.
Pros
Mounts up to four external direct cable SATA drives.
FIS-based Port Multiplier-aware hardware.
Mounts up to 20 external SATA drives using four PM enclosures.
Native PCI Express (PCIe) 4x host bus interface.
Spread Spectrum Clocking (SSC) support.
Supports OS X version 10.2 or later and Windows XP.
Performs faster than FireWire 800.
Allows data transfer to all four ports simultaneously.
Multitasks disk transfers which increases CPU efficiency.
Supports Power Mac G5 PCI Express bus.
User-upgradeable firmware.
48-bit LBA support for drive sizes larger than 137GB.
Easily mounts single drives or a RAID configuration.
No additional Mac drivers needed.
Supports deep sleep.
Well designed, easy to use and easy to install.
Cons
Does not work consistently in slot 3.
Does not support sleep with WiebeTech SilverSATA II.
Slower PCIe port multiplier write speed than when using PCI-X.
No boot capability.
Sonnet Tempo SATA E4P gets 4 AMUGs out of 5!
If you are looking for a high quality, feature rich SATA host adapter for a PowerMac G5 (Oct 2005) model with PCIe, your hunt is over. The Sonnet Tempo SATA E4P provides direct connection drive support, port multiplier compatibility, deep sleep, hot swap, Disk Utility RAID support, drive activity lights, eSATA ports, a native 4x PCIe implementation, Spread Spectrum Clocking (SSC) support and works well with both SATA I and SATA II hard drives. If these are features that you appreciate the Tempo E4P is definitely worth considering. Special thanks to Joel Vink of Sonnet for all of his help during the review process. The guys at Sonnet Technologies are great to work with.
Contact Information:
Sonnet Technologies, Inc.
8 Autry
Irvine, California 92618-2708 USA
Phone: 1-949-587-3500
sales@sonnettech.com
Copyright 2006
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