Sign in with
Sign up | Sign in
Your question

SSD Interface Comparison

Last response: in Systems
Share
a b B Homebuilt system
October 28, 2010 1:27:11 AM

PCIe SSDs have been available for some time now, but have failed it seems, to garner much attention. The most attractive drive available on Newegg currently is the RevoDrive from OCZ. It is available on Newegg in capacities ranging from 50 to 480 GB. What makes this drive interesting (besides the PCIe interface) is the fact that it utilizes dual SF-1222 drives in RAID 0 with an onboard controller. This fact, combined with the higher bandwidth of the PCIe interface relative to SATA 3Gb/s allows for some pretty impressive performance specs.

  • Read: Up to 540 MB/s
  • Write: Up to 480 MB/s
  • Sustained Write: Up to 400 MB/s
  • Random Write 4KB (Aligned): 75,000 IOPS

    OCZ RevoDrive 80GB

    Moreover, the drive seems to indicate room for potential future upgrades: the RAID controller supports up to four SandForce controllers (it only currently has two), and curiously enough there is a mysterious connector in the center of the card. The resulting configuration would be akin to SLI/Crossfire of dual GPU cards (e.g. HD 5970) with SSDs.

    Ok, so there are definite drawbacks to multi-SSD setups that many of you may be familiar with, i.e. TRIM support. Well, unfortunately this drive is no different from it's SATA counterparts in that respect - it lacks idle garbage collection. Nevertheless, it is important to remember that SandForce drives are fairly resilient and that no XP users can utilize TRIM anyway.

    I know many people are likely to say "That's why we have SATA 6Gb/s." I don't necessarily disagree, in fact that is part of the reason for this post - to get everyone's opinion regarding whether future SSDs will continue to be predominantly ported for the SATA interface or whether PCIe will gain traction. For reference, the retail price for the 80GB RevoDrive is exactly double the retail price of two 40GB Vertex 2s (both are currently on sale until November), which it generally slightly outperforms. What would PCIe drives need to offer in order to win you over? What are some advantages of the PCIe or SATA interface? Please share any thoughts you have on the subject or SSDs in general.
    a b B Homebuilt system
    October 28, 2010 2:30:08 AM

    The only major advantage of the PCI-E SSDs over SATA SSDs is the bandwidth. SATA III only allows a maximum of ~0.75 GBps (6Gbps), whereas PCI-E allows much higher speeds at around 1.4GBps (http://www.newegg.com/Product/Product.aspx?Item=N82E168...).

    I don't know if you can boot from a PCI-E SSD (doubt it, but idk for sure), but even then it is extremely limited by the speeds of the other components. I don't quite know what PCI-E SSDs are designed for...
    a b B Homebuilt system
    October 28, 2010 2:37:37 AM

    Booting would obviously be a pretty high priority for me to care at all about them.

    I'm not really sure why that's so hard though, I mean there are RAID controllers on that and you can boot from them as well as using network booting.

    While on the subject of transfer rates a super high theoretical number is only so useful, and if the standard method gives enough room that the device can function at max then I doubt most people would have a problem with just using SATA.
    Related resources
    a b B Homebuilt system
    October 28, 2010 2:44:27 AM

    Yes, the RevoDrive is bootable. I should have mentioned that in the OP.

    Edit: And yes, the enabling factor allowing for such high performance on the Revo is greater bandwidth offered by PCIe x4 I believe the x4 can support 20Gb/s versus 6 over SATA 6Gb/s.
    a b B Homebuilt system
    October 28, 2010 3:08:05 AM

    I would like to point out that altough the Revo is bootable there are a few quirks/incompatibilities with these PCIe SSDs with most boards. Until this is fixed, I don't see PCIe SSDs becoming mainstream soon. For Enterprise this kind of thing makes sense as they usually adopt these things first and/or need the performance. I would also like to point out that until we see native SATA> PCIe bridge chips become cheaper. It's a hassle from a technical perspective to go from SATA>PCI X>PCIe and depending on the controller,etc you may loose performance there (although not by much, if any).

    Anyways, if Sand Force is right, they could break SATA III already with their next SF 2xxx controller. It should be some fun next year. Hopefully Intel G3 will drive $/GB down.

    Quote:
    Ok, so there are definite drawbacks to multi-SSD setups that many of you may be familiar with, i.e. TRIM support.

    On Intel boards with the latest Intel RST drivers you can now run TRIM on RAID assuming Windows Vista/7 and AHCI enabled.

    Quote:

    Moreover, the drive seems to indicate room for potential future upgrades: the RAID controller supports up to four SandForce controllers (it only currently has two), and curiously enough there is a mysterious connector in the center of the card.

    IIRC, OCZ said this connector will not be used.

    Also, next time, please link to your benchmark sources: http://www.anandtech.com/show/3788/oczs-revodrive-pcie-...
    a b B Homebuilt system
    October 28, 2010 3:15:22 AM

    ^ That's very good to know regarding TRIM, thanks. Yeah, I just hope SandForce doesn't decide to strip down their consumer drives, since from what I've seen they will be significantly better performing than the G3s.
    a b B Homebuilt system
    October 28, 2010 9:10:31 PM

    Well, OCZ just introduced the new RevoDrive X2 today... Does this drive, now with four SandForce controllers for greatly improved performance as well as higher capacities, change your mind?
    a b B Homebuilt system
    October 29, 2010 1:52:05 AM

    ^ As long as the OCZ Revo X2 have PCIe compatibility issues, I would not recommend it unless the user knows EXACTLY what they will be dealing with. If it doesn't have and PCIe booting issues with most boards, then I would recommend it in certain cases assuming price isn't insane.

    Another thing is it's using PCIe x4. So unless you have a board with atleast 2x PCIe x16 (with 1x PCIe x16 not being used) then this card would not make sense. This eliminates a lot of boards out there esp. if the user plans to CrossFire/SLI. Hopefully, some of the board manufactures will stop giving us these useless PCIe x1 (and the ancient PCI) slots and give us x4 slots. Seriously, I have yet to find real use for my PCIe x1 slots.

    Again, like I said, this type of SSDs are for Enterprise (esp. Data base,etc) not so much as to consumer/mainstream currently. This is depending on pricing and compatibility with booting.
    a b B Homebuilt system
    October 30, 2010 3:42:57 AM

    Well I have a really good intel gigabit NIC in my x1. That's pretty much it though.
    a b B Homebuilt system
    October 30, 2010 3:54:24 AM

    ^ How many other PCIe x1 slots are you using? None? Exactly. If we just get a 1-2 PCIe x4 slots we can actually use these PCIe SSDs with out having to give up CrossFire,etc.
    a b B Homebuilt system
    October 30, 2010 5:23:43 AM

    My mobo is micro-ATX, so there is only one other x1 and it's too busy being covered up by a dual slot graphics card to be able to be used. That's another problem that's annoying.
    a b B Homebuilt system
    October 30, 2010 3:15:51 PM

    I'm thinking about building a home server, and if these get cheap enough, they are definitely going in it.
    !