PCIe Speed Test v0.1 CPU-GPU/GPU-CPU bandwidth test

[Mechromancer]

So many questions here...

I wonder if ATI chipset engineers understand that a single GPU needs this amount of bandwidth, with the assumption being the other PCIe slots may be used by other devices. I personally use a x8 RAID controller and an x1 TV Tuner. A person with a multi-GPU system is the type of person that wants full bandwidth for their GPUs and probably doesn't have the other PCIe slots populated with any other type of device. The system allows the GPUs to have as much bandwidth as they can get in this case.

That explanation is ok, but it still begs the question, why not give each slot what it asks for regardless of the device type? If you have one GPU with no other devices on the PCIe bus, it should get all the bandwidth you can throw at it. If you have a setup like mine, then my 790FX should give my x16, x8, and x1 cards what they're asking for. I will take a look at my BIOS to make sure each individual slot is given what I want it to have (gotta love the M3A79-T Deluxe bios). Modern Intel and AMD chipsets have a set number of PCIe lanes to work with. The slot and peripheral PCIe config on the boards is set up such that you don't run out of lanes. I don't see why my x16 slot can't give full x16 bandwidth bi-directionally as is the PCIe spec. If this is an intentional driver bandwidth limit, I want an explanation as why it HURTS performance. The only reason to limit anything in my XTREME point of view is because it yields diminishing returns, which hopefully is the case.

Still, lets figure out if it's the driver or motherboard that is doing this. Can we get any Intel Core i7 X58 and Core 2 guys with ATI GPUs to run this program? This will let us know if it is a chipset or display driver issue, if those at all.