Does it matter which PCIe slot my video card goes into?

[NTAC]

If I have two 16x slots, does it matter?

 

[NoQuarter]

It shouldn't but I think I've read of some mobos having issues if you don't fill the PCI-e slot nearest the CPU first.

 

[Lonyo]

It depends on the mobo.
Some have a second slot which only runs at a reduce speed (e.g. x16 for first, x4 all the time for the second), some have a second slot which will only run when both slots are set to a slower speed (both get set to x8/x8, or the second will be at x1 with the first at x16), and some have a second slot which will run at full speed (both will be x16/x16).

It depends on the motherboard and chipset, there's no set rule. So yes, it might matter, or it might not.

 

[NTAC]

This is the MOBO: http://www.newegg.com/Product/Produc...-400-_-Product

Says 2 x PCIe 2.0 x16 (single at x16 or dual at x8/x8 mode)

This leads me to believe that either PCIe will run 16 by itself, and 8 if its sli/crossfire... correct?

 

[Lonyo]

Nope.

Either you get x16 / nothing / x4
or you get x8 / x8 / x4

 

[NTAC]

Nope.

Either you get x16 / nothing / x4
or you get x8 / x8 / x4

So with this mobo, even if I'm just using 1 card, I can only get 16x in the first PCIe slot?

 

[NoQuarter]

So with this mobo, even if I'm just using 1 card, I can only get 16x in the first PCIe slot?

Yea, if the mobo is something like 16x/8x only the first PCIe slot will operate at 16x no matter what. They save money by not tracing as many PCIe lanes to the further slots so it's just not possible. I had assumed from your first post they were 16x/16x my fault. The max slot speeds are listed from first to last.

 

[NTAC]

Yea, if the mobo is something like 16x/8x only the first PCIe slot will operate at 16x no matter what. They save money by not tracing as many PCIe lanes to the further slots so it's just not possible. I had assumed from your first post they were 16x/16x my fault. The max slot speeds are listed from first to last.

Sheesh, they should really do a better job of listing this, cause when I see:

2 x PCIe 2.0 x16 (single at x16 or dual at x8/x8 mode)

I think, ok, there's 2 PCIe 2.0 x16 slots on the MOBO.

Single at x16, so I think, either one at x16, or dual at x8/x8, where I think if I fill both then they each run at 8x.

So I understand that i only get 8x if I do crossfire / SLI, but I'm surprised that the 2nd slot will not do 16x if its by itself.

Oh well, not a deal breaker by any stretch, I just hope the 260 GTX will be able to fit in that first slot with the Noctua NH-D14 in there. I'll cross my fingers

I was looking at a review that said this:

This board has a lot of overclocker-friendly features, such as on-board DIP switches to control voltages. You'll notice in the photo shoot that is comes with 3x 16x PCIe slots 2.0 two of which are split off from the main PCI-E bus coming directly from the CPU. When a single slot is populated, it will run at x16 but for SLI and CrossFire, the slots will run at x8/x8/x4.

So they say when a "single" slot is populated.. should they have specified the 1st slot only?

 

[Dark4ng3l]

Just try it and look in GPU-Z to make sure it's running at 16x.

 

[NTAC]

Just try it and look in GPU-Z to make sure it's running at 16x.

Yeah for sure, I'll try that, but hopefully I can just use the 1st slot, we'll see.