Abit IP35 Pro - PCIe question - 2nd slot 4x or 16x

Just a quick question. I purchased a EVGA 8800GTS 512 PCIe video card and this thing is big. It won't fit in the PCIe slot 1 because of my case and hard drive location.

It does fit in the second PCIe slot. I thought I read that this board will drop from 16x to 4x if using two video cards.

According to the documentation it drops to 4x if I only use PCIe slot 2.

Do not install only one PCI Express
graphics card on slot [PCIEXP2], for
such an act will pull its speed down
to x4 only.

Can anyone clarify the speeds of each slot when used by itself or in CF? I know this dual setup doesn't apply to me because I'm not using ATI cards but I would like to understand each scenario.

Thanks in advance.

That will be a problem

I'm not sure how much slower it will run if you put it in the 4x slot, but it will almost certainly run slower than it could.

according to something I read at THG, you will lose 20-30% using the 4x pci-e slot, even though the slot is physically a pci-e x16 slot.

I think electrically the second slot is only 4x at max, even though you aren't using the first pci-e x16 slot.

EDIT: Sounds like it's time to either rearrange the hard drives or get a new case.

It will run in x4 in the second slot. If you're not using any other PCIe x1 cards.

It will be like ~10% slower could be more, could be less.


Atleast that is the numbers when i benchmarked my 8600GT and my 8800GT in x4 vs x16.


Using a single GPU or CF (doesn't matter, the speeds will be the same)
1st x16 slot will give x16
2nd x16 slot will give x4 (if you're not using any PCIe x1 cards)
If using one or more PCIe x1 cards besides the GPU, it will drop down to x1 on the 2nd x16 slot.

The 2nd x16 slot is commonly shared with the other PCIe x1 slots on the P35 or earlier boards with dual pcie x16 slots, so the bandwidth will be shared on the 2nd x16 and the x1 slots. If you know what i'm saying Haven't read about any other boards that doesn't share the 2nd x16 slot with the rest of the x1 slots (when it comes to P35 or 975x or such).

Thanks guys. I've got 4 HDD's in the system and I'm going to move the bottom two which will clear space for me to use the Slot 1 PCIe.

Thanks.

Moved a HDD to a different location and was able to get the card into PCIe slot 1. Thanks guys.