Asus P6X58D Premium Question about PCI Lanes

[fsardis]

So I have this mobo and now I was wondering how many lanes feed the USB-3 and SATA-3 controllers. For SLI/Crossfire the card runs either 16/16/1 or 16/8/8. I don't know how many lanes that leaves free for other devices. I know that there is also one PCIE x1 slot.
Can someone shed some light? I have searched everywhere and I can't find an answer.
I am trying to find out if there will be a bottleneck when running a couple of fast SATA-3 SSD in parallel or a couple of USB-3 devices in parallel or even all at once.

 

[sgrinavi]

From a practical standpoint - I wouldn't worry about flooding your lanes, the new quadro 6000 cards are rated at 144 GB/Sec and are not held back by the x16 bus.... _
I run a pair of GTX 480's on mine with a pair of SSDs, albeit SATA II, and there was never an issue with their being bottle-necked regardless of my video card configuration.

 

[fsardis]

Hi, thanks for the reply. I am not worried about affecting GPU performance. What worries me is that if I use two SATA-3 SSDs there will not be enough PCI-E lanes dedicated to the SATA-3 controller. That's why I am asking if anyone knows how many lanes are dedicated to the SATA-3 controller on this mobo and if they are PCI-E 1.0 or 2.0
Similarly for USB-3, I have no idea how many lanes are dedicated to the USB-3 controller and if they are 1.0 or 2.0 spec.
So basically, if I do have a couple of SATA-3 spec SSD's one day and a try a few simultaneous file transfers between those, will I run into a bandwidth wall because of insufficient lanes or will I be fully using SATA-3 bandwidth? Same question applies to USB-3.
Any ideas?

 

[sgrinavi]

My point was that I am using the board at nearly it's full potential and am still getting amazing xfer rates

For all practical purposes I wouldn't worry about the exact numbers.....

 

[fsardis]

I see Intel RAID0 volume there which means you are using the SATA2 ports on your mobo. These have nothing to do with the Marvell SATA3 controller on the mobo. I was asking if that controller poses a bottleneck in the performance of SATA3 devices.
By the way, given that the controller devices have dedicated lanes for their bandwidth, it is irrelevant how many GPUs you have or if you are using it all at once. Each lane still has 500MB/s aggregate so the bottleneck would be the CPU if you do see a performance drop. That being said, the SATA2 ports that you are using are part of he southbridge and do not use PCI-E lanes like NICs or other controllers.

Anyway, I found the spec of the Marvell controller and it only uses 1 PCI-E lane which means it is only good for one SATA3 SSD and even then it will be limiting it's bandwidth if we assume an SSD to actually reach the limit of SATA3. That means that connecting two SATA3 SSDs on that controller is going to be a bandwidth disaster.
Sadly the news don't get any better in regards to the NEC USB3 controller. It too uses only 1 PCI-E lane which means it is only good to provide full bandwidth for 1 USB3 device.

Hope this helps someone in the future.