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Written by Olin Coles   
Wednesday, 22 September 2010
Table of Contents: Page Index
OCZ RevoDrive PCI-Express SandForce SSD
Features and Specifications
Closer Look: OCZ RevoDrive PCI-E SSD
SandForce PCI-E SSD Anatomy
SSD Testing Methodology
AS-SSD Benchmark
ATTO Disk Benchmark
CrystalDiskMark 3.0 Tests
Iometer IOPS Performance
EVEREST Disk Benchmark
HDD vs Hybrid Drive vs SSD
OCZ RevoDrive Conclusion

SandForce PCI-E SSD Anatomy

The SandForce SF-1200 SATA-3GBps controller is a durable component. SandForce features DuraClass technology on their SF-1200 processor, which claims to provide best-in-class endurance, performance, and lower power consumption. DuraWrite technology extends the endurance of MLC-NAND memory by providing at least five year lifecycles measured with 3000-5000 cycle MLC flash. Additionally, SandForce RAISE technology provides RAID-like protection for single SSD computer systems, and data is secured with AES-128 automatic encryption.

It's easy to mistake the OCZ RevoDrive for two SandForce SF-1200 SSDs combined into RAID-0, which oversimplifies things. There are two primary components to the average SandForce-driven SSD: a single storage controller and flash memory. The OCZ RevoDrive is comprised of four primary components: PCI-Express bridge, RAID controller, dual storage controllers, and flash memory. Some might consider these differences minor semantics, but in truth they contrast a simple storage device (SSD) against a more complex RAID system on the PCI-Express platform.

The first evidence that this isn't your average SSD comes when you boot-up the computer and are given the opportunity to enter the Silicon Image RAID Configuration Utility. Since the SiI3124 chip used on Revo is identical to those used on many desktop motherboards and RAID controllers, users will find it very familiar. The OCZ RevoDrive has two 'drives' permanently attached, so many of the RAID options are available but unusable (RAID-5/10). Users can destroy the RAID set and rebuild it using smaller or larger stripe sizes, although our SandForce SF1200 RAID-0 SSD Performance article has demonstrated that larger stripes are better for SSDs.

OCZ-Revo-Drive-SSD-Silicon-Image-RAID.jpg

Silicon Image SiI3124 RAID Configuration Utility

When the OCZ Revo SSD is installed into a Windows 7 (64-bit) computer system as a secondary drive, the device manager prompts for driver installation which indicates a lack of Plug-n-Play compliance. OCZ includes the necessary SiI3124 drivers with the Revo SSD kit, as well as their website. As of September 2010 these drivers were identical to the latest package available direct from Silicon Image (si3124r5_15230_x64_Logo).

OCZ-Revo-Drive-SSD-Device-Manager.png

Windows 7 Device Manager

SandForce-driven SATA SSDs are capable of connecting to various controller hosts, such as those from Marvell or Intel, which retain TRIM garbage collection functionality as well as AHCI mode features. SandForce-driven PCI-Express form factor devices have their own host controller, and lose this functionality as a result. This is why the SandForce PCI-E SSD anatomy becomes important to understand.

The Pericom PI7C9X130 PCIe-to-PCIx reversible bridge chip is straight-forward in purpose and functionality, as it connects the PCI-Express x4 port to one standard 64-bit /133 MHz PCIx port which messages the Sil3124 RAID controller chip. This is where the magic happens, as Silicon Image defines their SiI3124 chip as a PCI-Express to SATA-3GB/s controller capable of driving four ports. The current version of OCZ's Revo SSD incorporates the Sil3124 chip to drive two of the four available channels, using two SandForce SF-1200 controllers combined into a RAID-0 array to produce peak performance before reaching a collection of NAND flash components.

SiI_3124_Diagram.png

SiI3124 Block Diagram (Courtesy Silicon Image)

The SATA 3Gb/s SandForce SF-1222TA3-SBH processor utilizes a Tensilica Diamond Core DC_570T internal CPU. SandForce-driven SSDs include either a SF-1200 processor for retail consumer products, or the SF-1500 for enterprise storage devices. While all SandForce SSDs offer native TRIM garbage collection (Microsoft Windows 7), Native Command Queuing (NCQ) with 32 command slots, and Self-Monitoring, Analysis, and Reporting Technology (SMART) command set, they cannot be passed-through to the Silicon Image SiI3124 RAID chip with current driver support unlike Intel's ICH10 does with the Rapid Storage Technology software. Regardless, the SF-1200 controller does an excellent job of minimizing re-write delays associated with dirty NAND.

SandForce_SF-1222TA3-SBH_Processor.jpg

SandForce SF-1222TA3-SBC Processor

A key benefit to SandForce's SF-1200 architecture is that the SSD keeps all information on the NAND grid and removes the need for a separate cache buffer DRAM module by using the SandForce DuraClass technology. This results in a faster transaction, albeit at the expense of total storage capacity. SandForce SSDs also utilize over-provisioning technology, which allocates a portion of NAND for data storage and the remainder reserved for transaction and cache buffer space.

The SF-1200 SSD processor provides ECC data protection and includes SandForce's unique RAISE (Redundant Array of Independent Silicon Elements) technology. RAISE provides the protection and reliability of RAID on a single SSD drive, thanks to flash architecture, without the significant write overhead of parity. The SandForce DuraClass technology automatically stores data in AES-128 encrypted format, preventing data extraction directly from the physical flash memory modules.

Micron-Intel_DRAM_29F64G08CAMDB.jpg

Intel 29F64G08CAMDB NAND Flash IC

Several multi-layer cell (MLC) Intel 29F64G08CAMDB NAND flash modules are joined to the SandForce SF-1200 controllers. On the 128GB Revo SSD model (OCZSSDPX-1RVD0120) these NAND modules combine for 128GB of physical storage space, yet only 100GB of this capacity is designated for data. Consumer-level SandForce SSDs receive 7% over-provisioning and 128GB devices will yield 120GB of usable storage space.



 

Comments 

 
# RE: OCZ RevoDrive PCI-Express SandForce SSDfunkz 2010-09-22 01:52
Page 4 incorrectly states "Silicon Image defines their SiI3124 chip as a PCI-Express to SATA-3GB/s controller" when it's PCI-X as listed elsewhere in the review. The SiI3124 is ancient, strange that OCZ would choose to use it since the PCI-E has to be bridged to PCI-X first with the Pericom, when there are native PCI-E RAID controllers readily available, such as the SiI3132 for example. But why even bother using SATA on a card? Instead of this convoluted process of PCI-E to PCI-X to SATA RAID to NAND, how about a simple PCI-E NAND controller?
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# Platform dependant?RealNeil 2010-09-22 02:45
I wonder if the drive would perform as well on a P55 mainboard?
They have certain bandwidth restrictions on the PCI-E bus with multiple PCI-E slots occupied concurrently. (X16 is divided into X8 times two)
I just wonder if this architecture would effect the output of the drive, and if the drive would effect the output of the Video Card?
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# DESEMPENHO DOS DRIVES SSDSandro 2010-09-22 03:27
VEJA SO, SANDRO, QUE A INDUSTRIA TENTOU COLOCAR UM PREÇO ALTO NESTE TIPO DE "STORAGE DEVICE" MAS... NAO COLOU.
PARECE QUE VAO MUDAR A TATICA!
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# RE: DESEMPENHO DOS DRIVES SSDRealNeil 2010-09-22 03:54
Did he say?: SO SEE, SANDRO, THAT TRIED TO PUT AN INDUSTRY'S HIGH PRE THIS KIND OF "STORAGE DEVICE" BUT ... Not getting through. IT SEEMS THAT WILL CHANGE THE TACTIC!
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# TranslationGustavo 2010-09-22 22:50
What he said can roughly be translated as( not translated work by word, but a little better translation): "You see, Sandro,the industry tried to put a high price in this type of Storage device...but it didnt worked out. Now it look like they are going to change tatics."

Aside from the tranlation, can someone tell me if this type of storage( via Pci-e)is bootable??
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# RE: TranslationRealNeil 2010-09-23 04:25
Ha-Ha! I used Google Translate on it and that's the best it would do for me. I don't understand Portuguese at all. You've made it much clearer to me what he meant. Thank You.
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# RE: TranslationRealNeil 2010-09-23 04:30
As to the bootable, check OZC's site for more info on this device. It's bootable with some motherboards and is not with others.
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# RE: TranslationAdam 2010-09-23 04:33
It is, although it's fairly dependant on the motherboard.

I'd guess quite a lot will need bios updates.
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# RE: RE: TranslationOlin Coles 2010-09-23 06:55
Most current-generation motherboards will support Revo as a boot device, such as Intel's 5x series and AMD's 8xx series, but older motherboards may require a BIOS update.
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# RE: OCZ RevoDrive PCI-Express SandForce SSDRobert17 2010-09-22 04:26
Nice review. Couple of questions: this drive is very reminiscent of the ANS-9010 product which I felt at the time was very forward-looking. Any chance that this could be THE direction SSD products will be headed by all manufacturers? (I'm guessing that you are provided a bit more insight on an average day)

I notice the idle power consumption on the data sheet provided by OCZ is 7W. Although still small, it seems to be much higher than other SSDs. Is this correct? If so, is it an artifact of having two controllers on the card or of being a PCI-E footprint? Any idea?
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# AnswersOlin Coles 2010-09-22 07:50
@ funkz: Page 4 is actually correct, as I re-state Silicon Image's product description: siliconimage.com/products/product.aspx?pid=27
I agree with you about the controller; it works, but better options exist. Perhaps it was a cost benefit issue.

@ Neil: OCZ doesn't recommend motherboards with restrictive bandwidth on the PCI-Express bus, and the P55 motherboard would be a concern if SLI or CFX were used. If it's a single VGA with Revo on P55, I don't see a problem.

@ Robert: A standard SSD has a controller and NAND, while the Revo has twice the amount of NAND ICs, a RAID processor, and PCI-E bridge. This is where the extra power consumption comes from.
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# Beware Crosshair IV ownersJethro 2010-09-22 08:31
Be careful about purchasing the Revodrive before checking compatibility on OCZ's site. The Crosshair IV and I think the EVGA X758 SLI board does not work with the Revodrive. ASUS has yet to fix their BIOS to enable the drive to work and I don't know about the EVGA.
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# RE: Beware Crosshair IV ownersOlin Coles 2010-09-22 08:37
To be more specific, Jethro is referring to the OCZ RevoDrive as the computer's boot drive. It will still work as a secondary drive.
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# liveonc.weebly.comJay 2010-09-23 08:52
Would have preferred if they offered a PCIe 2.0 x16 SSD with 4-8 SiI3124 in 16 RAID 0 or 8 RAID 1+0 even if it's "only" a 120GB SSD, to make most of the cheap PCI-X controller & most of the MLC-NAND memory using all 16 PCIe lanes.
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