Installing 6Gb/s SATA SSD's on Alternative SATA Controllers Installing an Intel 520 SSD into a system with 3Gb/s SATA ports

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1 Most of the latest SSD's use a 6Gb/s SATA interface, and can only reach their maximum performance when connected to a 6Gb/s SATA controller port. Unfortunately, most older motherboards only have 3Gb/s ports, or even 1.5Gb/s for earlier motherboards. These older motherboards will not support the maximum performance of the latest SSD's, and restrict them to lower data transfer rates. In order to maximise SSD life, and to maintain on-going SSD performance, SSD's should only be used on controllers that pass TRIM commands, with drivers that support TRIM, and running under an OS that can generate TRIM commands (Windows 7 and 8). SATA Rev 3.0 Controllers The first 6Gb/s SATA controllers were the Marvell 88SE91xx series, and some current motherboards still use this chip for on-board 6Gb/s SATA ports. Unfortunately, these Marvell controllers only have a 1x lane PCIe2.0 bus (5Gb/s), which limits their performance (up to about 30%). A more recent alternative to the Marvell 88SE91xx is the ASMedia ASM1061 controller. This is a simple 2-port SATA Rev 3.0 device, which also works off a 1x lane PCIe2.0 bus. Reports suggest that the ASM1061 is slightly faster than the 88SE91xx. The very latest motherboards with an Intel PCH chipset (Series 6 onwards) have embedded 6Gb/s SATA controllers, and are excellent SATA 6Gb/s devices which can work at the full 6Gb/s rated speed. A Marvell SATA Rev3.0 controller with a faster 2x lane PCIe2.0 interface, the 88SE92xx series, was released in January This eliminates the bottleneck associated with the 1x lane PCIe2.0 devices, and was made possible by a change to the PCI Express standards. The chip is built in to some recent motherboards, but at the time of writing has not yet made it into add-in expansion cards. Tests on 88SE92xx equipped motherboards (see here) show that it is similar in speed to the embedded Intel 6Gb/s controller. Page 1 of 11

2 Add-In SATA Rev3.0 Expansion Cards For systems having motherboards without any on-board 6Gb/s SATA controllers, an add-in expansion card can be used. Most simple add-in SATA 6Gb/s controllers use the Marvell 88SE91xx chip, but a some use the alternative ASMedia ASM1061. Asus U3S6 The Asus U3S6 add-in card has a 88SE9123 or a 88SE9120 controller which provides two 6Gb/s SATA ports. The U3S6 also has a NEC/Renesas μpd USB3.0 controller that provides two SATA3.0 ports. Unfortunately, the USB controller is also connected via a 1x lane PCIe2.0 bus, again limiting USB performance. To obtain the optimum performance, the U3S6 card must be connected to at least a 4x lane PCIe2.0 slot, and only should only be connected to a single SSD. The U3S6 has a boot ROM, and the SATA controller is bootable. The standard firmware installs AHCI mode. The Marvel 88SE91xx controller can either be used with the Marvell AHCI driver or with the standard Microsoft AHCI driver. The Marvell controllers will pass the TRIM command (in simple by-pass mode), but the Marvel drivers do not support TRIM. Only the Microsoft AHCI driver will pass TRIM to the SSD through the Marvell controller. The Marvell driver installs the device as a SCSI Miniport, whereas the Microsoft driver installs as an IDE ATA/ATAPI Controller. The driver can be changed by selecting the alternative in the Device Manager. Syba SY-PEX40039 The Syba SY-PEX40039 add-in card uses the ASM1061 controller, with a 1x lane PCIe2.0 interface, and provides 2x SATA Rev3.0 ports. Since the card only has a 1x lane interface, using 2 SSD's on the controller should be avoided. The Syba SY-PEX40039 has a boot ROM, is bootable, and the firmware is set to install AHCI mode. The controller passes TRIM commands to the SSD, and can be used with the standard Microsoft AHCI (msahci) or the ASMedia AHCI drivers, both of which support TRIM. The ASMedia AHCI driver, and the Microsoft AHCI driver, both install the device as a IDE ATA/ATAPI Controller. The driver can be changed by selecting the alternative in the Device Manager. Intel The Intel 3Gb/s & 6Gb/s SATA controllers are embedded in the PCH/Southbridge, and both pass TRIM commands. The Intel RST driver also supports TRIM in a single drive mode, but at the moment not to members of a RAID array. The Microsoft AHCI driver can only be used, as the default, when the Intel RST driver is not installed. The BIOS must be set to AHCI or RAID, and the Intel RST driver installs as a SCSI Miniport device. Page 2 of 11

3 Testing SATA Controllers and Drivers To determine the best way to connect an Intel GB SSD to a system without built-in 6Gb/s SATA ports a series of tests were conducted:- 1. Intel GB, Marvell 88SE9120, Microsoft AHCI driver (msahci) 2. Intel GB, Marvell 88SE9120, Marvell driver (mvs91xx) 3. Intel GB, ASMedia ASM1061, Microsoft AHCI driver (msahci) 4. Intel GB, ASMedia ASM1061, ASMedia 106x AHCI driver (asahci64) 5. Intel GB, Intel ICH10R, Intel RST driver (iastor) 6. Intel /240GB, Intel Series 6 SATA, Intel RST driver (iastor) - third-party benchmarks for reference of ultimate performance 7. RAID 10 array of 4x WD Caviar Black (WD5001AALS), ICH10R, Intel RST driver (iastor) - for reference and interest only Test System:- Intel Core i7 980 processor Asus P6T Deluxe motherboard 12GB Corsair XMS3 Memory (TR3X6G1333C9) Vista 64 Home Premium SP2 Test Drive: Intel GB SSD installed as a data drive System Drive: RAID 10 array of 4x WD Caviar Black (WD5001AALS) HDD's Expansion cards:- Asus S3U6 (88SE9120/ PEX8608/ D720200F1) in 16x lane PCIe2.0 slot Syba SY-PEX40039 (ASM1061) in 16x lane PCIe2.0 slot To provide a reference of ultimate 6Gb/s SATA SSD performance, typical third-party test results are included for the Intel 520 connected to a 6Gb/s Intel SATA controller on a P67 motherboard. Page 3 of 11

4 AS SSD Benchmark Results Intel 520, U3S6, Microsoft Driver Intel 520, U3S6, Marvell Driver Intel 520, ASM1061, Microsoft Driver Intel 520, ASM1061, ASMedia Driver Intel 520, ICH10R, Intel Driver Intel 520, Intel P67, Intel Driver Page 4 of 11

5 RAID10 HDD, ICH10R, Intel Driver Page 5 of 11

6 CrystalDiskMark Benchmark Results Intel 520, U3S6, Microsoft Driver Intel 520, U3S6, Marvell Driver Intel 520, ASM1061, Microsoft Driver Intel 520, ASM1061, ASMedia Driver Intel 520, ICH10R, Intel Driver Intel 520, Intel P67, Intel Driver Page 6 of 11

7 RAID10 HDD, ICH10R, Intel Driver Page 7 of 11

8 ATTO Benchmark Results Intel 520, U3S6, Microsoft Driver Intel 520, U3S6, Marvell Driver Intel 520, ASM1061, Microsoft Driver Intel 520, ASM1061, ASMedia Driver Intel 520, ICH10R, Intel Driver Page 8 of 11 Intel 520, Intel P67, Intel Driver

9 RAID10 HDD, ICH10R, Intel Driver Page 9 of 11

10 Observations & Discussion The 6Gb/s Marvell and ASMedia controllers, used with the standard Microsoft driver, produce sequential read and write speeds virtually the same as when using the Marvell and ASMedia proprietary drivers. For smaller random transfers the Microsoft driver gives very inferior data rates, especially at the larger queue depths. The access times are also significantly worse with the Microsoft driver. It would appear that the Vista (64-bit) in-box Microsoft AHCI driver is not optimised for NCQ or small block transfers - at least with these controllers. This may be a characteristic of the Vista driver, because the Windows 7 standard Microsoft AHCI driver is widely reported to work well with SSD's. Overall, the ASMedia controller is faster than the Marvell controller, and in particular has a better balance between read and write speeds. A major advantage of the ASMedia device is that both the controller and driver pass TRIM. The Marvell only passes TRIM with the Microsoft driver, but with very poor transfer speeds. The ASMedia controller with the ASMedia driver is currently the best addin controller. The Intel ICH10R 3Gb/s controller, with the Intel RST driver, produces overall speeds slightly lower than those obtained from the 6Gb/s ASMedia/ASMedia controller and driver combination. The Random transfers are virtually the same, the queued random transfers are lower, but with similar access times. Naturally, the Intel controller has worse sequential speeds due to it being a 3Gb/s SATA device rather than a 6Gb/s type. The 6Gb/s ASMedia controller and driver combination is better on virtually every score than the 3Gb/s Intel/Intel setup. If an Intel 6Gb/s SATA port is not available, and since it is important to use an arrangement that fully supports TRIM, the best controller is the ASMedia/ASMedia combination. However, the 3Gb/s Intel/Intel RST combination is better than the Marvell/Microsoft set-up, especially for system drives, where most data transfers will be highly random. Sequential transfer speed is less important for system drives. The Intel 6Gb/s controller with the Intel RST driver gives the best results of all, although as a system drive its speed benefits with random transfers may not be very noticeable in practice. As a data drive the higher sequential speeds would be beneficial with large file transfers. If the ultimate performance with an add-in controller is required it would be wise to look out for a new 6Gb/s expansion card, using the Marvell 88SE92xx controller, becoming available. There has been much discussion about whether the Marvell 88SE91xx supports TRIM. Results from using the Intel SSD Toolbox results clearly show that although the controller does pass TRIM, the latest Marvell driver (version ) does not pass TRIM. It has been reported (see here and here) that Marvell claim the driver was developed for OS's which do not have ACHI drivers (i.e. pre- Vista systems), and recommend that the Microsoft AHCI driver is used with Vista and Windows 7. It is also reported that the Marvell driver will never pass TRIM because these legacy OS's, for which it was written, do not generate the necessary TRIM commands. Page 10 of 11

11 It has not been determined whether the Intel RST driver is better than the Microsoft AHCI driver on the Intel SATA controllers, but many users report that the Intel RST is marginally better. Although the tests were made with a 64-bit Vista system all results, with the possible exception of those for the Microsoft AHCI driver, will carry over and be true for Windows 7 & 8 based systems. Conclusions 1. The Marvell 88SE91xx SATA controller passes TRIM commands (in by-pass/non-raid mode). 2. The latest Marvell driver ( ) gives good overall performance with the Marvell 88SE91xx SATA controller, but does not pass TRIM commands. 3. The ASMedia ASM1061 produces the fastest speeds of the currently available add-in 6Gb/s SATA controllers. 4. The ASMedia ASM1061 controller passes TRIM commands. 5. Both the ASMedia driver ( ) and the Microsoft AHCI driver ( ) support TRIM commands with the ASMedia ASM1061 controller. 6. The 3Gb/s Intel controller, with the Intel RST driver, gives speeds approaching those of the ASMedia ASM1061 and ASMedia driver, especially when used for a system drive. 7. The Intel 6Gb/s SATA controller gives the best results of all, but as a system drive it may not show a large improvement over the ASMedia/ASMedia controller/driver configuration. 8. Wherever possible always connect a 6Gb/s SSD to an Intel 6G/s SATA controller. 9. The Microsoft AHCI driver ( ), standard with Vista 64-bit, performs very badly with random transfers, especially with queued transfers, and its use should be avoided. Subsequent testing has shown that the Windows 7 AHCI (msahci) and the Windows 8 AHCI driver (storahci) both perform almost identically to the ASMedia ( ) driver. 10. Future add-in cards, using the new 6Gb/s Marvell 88SE92xx controller, will probably have a performance as good as the Intel PCH 6Gb/s SATA controller. Page 11 of 11