The Test Platforms

To see how much we’d be limited by Intel’s PCIe 1.0 slots and AMD’s new SB850, I put together a handful of test platforms.

I’ve got ASUS’ 890GX motherboard equipped with native 6Gbps SATA support. This board/chipset should give us full bandwidth to the Crucial RealSSD C300:


ASUS' M4A89GTD Pro/USB3

I’ve got Intel’s own X58 motherboard. With no on-board 6Gbps support I installed my RocketRAID 62X card into a PCIe 2.0 x16 slot, a PCIe 1.0 x4 slot and a PCIe 1.0 x1 slot.


Intel's DX58SO

Gigabyte sent its X58-UD3R motherboard, which has a Marvell 6Gbps controller branching off one the X58’s PCIe 2.0 lanes.

Next up is Intel’s P55 board where I use one of the x16 slots branching off the CPU socket, as well as a PCIe 1.0 x1 slot from the PCH. The results here should be equal to a H55/H57 platform, which I also verified.

Finally I’ve got ASUS’ P7H57D-V EVO with the PLX solution, just to see how well combining a bunch of PCIe 1.0 lanes to feed Marvell’s 6Gbps SATA controller works.

The C300 and What About P5x/H5x? The First Test: Sequential Read Speed
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  • vol7ron - Thursday, March 25, 2010 - link

    It would be extremely nice to see any RAID tests, as I've been asking Anand for months.

    I think he said a full review is coming, of course he could have just been toying with my emotions.
  • nubie - Thursday, March 25, 2010 - link

    Is there any logical reason you couldn't run a video card with x15 or x14 links and send the other 1 or 2 off to the 6Gbps and USB 3.0 controllers?

    As far as I am concerned it should work (and I have a geforce 6200 modified to x1 with a dremel that has been in use for the last couple years).

    Maybe the drivers or video bios wouldn't like that kind of lane splitting on some cards.

    You can test this yourself quickly by applying some scotch tape over a few of the signal pairs on the end of the video card, you should be able to see if modern cards have any trouble linking at x9-x15 link widths.
  • nubie - Thursday, March 25, 2010 - link

    Not to mention, where are the x4 6Gbps cards?
  • wiak - Friday, March 26, 2010 - link

    the marvell chip is a pcie 2.0 x1 chip anyway so its limited to that speed regardless of interface to motherboard

    atleast this says so
    https://docs.google.com/viewer?url=http://www.marv...">https://docs.google.com/viewer?url=http..._control...

    same goes for USB 3.0 from NEC, its also a PCIe 2.0 x1 chip
  • JarredWalton - Thursday, March 25, 2010 - link

    Like many computer interfaces, PCIe is designed to work in powers of two. You could run x1, x2, x4, x8, or x16, but x3 or x5 aren't allowable configurations.
  • nubie - Thursday, March 25, 2010 - link

    OK, x12 is accounted for according to this:

    http://www.interfacebus.com/Design_Connector_PCI_E...">http://www.interfacebus.com/Design_Connector_PCI_E...

    [quote]PCI Express supports 1x [2.5Gbps], 2x, 4x, 8x, 12x, 16x, and 32x bus widths[/quote]

    I wonder about x14, as it should offer much greater bandwidth than x8.

    I suppose I could do some informal testing here and see what really works, or maybe do some internet research first because I don't exactly have a test bench.
  • mathew7 - Thursday, March 25, 2010 - link

    While 12x is good for 1 card, I wonder how feasible would 6x do for 2 gfx cards.
  • nubie - Thursday, March 25, 2010 - link

    Even AMD agrees to the x12 link width:

    http://www.amd.com/us-en/Processors/ComputingSolut...">http://www.amd.com/us-en/Processors/Com.../0,,30_2...

    Seems like it could be an acceptable compromise on some platforms.
  • JarredWalton - Thursday, March 25, 2010 - link

    x12 is the exception to the powers of 2, you're correct. I'm not sure it would really matter much; Anand's results show that even with plenty of extra bandwidth (i.e. in a PCIe 2.0 x16 slot), the SATA 6G connection doesn't always perform the same. It looks like BIOS tuning is at present more important than other aspects, provided of course that you're not an x1 PCIe 1.0.
  • iwodo - Thursday, March 25, 2010 - link

    Well we are speaking in terms of Gfx, with So GFX card work instead of 16x, work in 12x. Or even 10x. Thereby saving IO space,just wondering what are the status of PCI-E 3.0....

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