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Lauwenmark78
10-27-05, 09:09 AM
http://users.skynet.be/chachkoff/nvidia_strange.jpg

As you can see, my 6600GT card is properly recognized - yet with a PCI-Express 1x bus, instead of 16x.

Note that I was able to reproduce the same bug with both the 78.05 (shown here) and 81.85 versions of the driver.

Any clue about this ? Is there a way to solve it ?

Configuration: CPU: AMD 3500+, MB: Asus A8N SLI Deluxe, GeForce 6600GT 128MB (Point of View), 2x512MB DDR400.

AthlonXP1800
10-27-05, 10:20 AM
:lol: PCI Express x1

Strange! Did you tried Forceware 81.87 beta driver?

Lauwenmark78
10-27-05, 12:04 PM
Yes - same result.

AthlonXP1800
10-27-05, 12:17 PM
Hmmm I noticed you got ASUS A8N SLI Deluxe, make sure you config SLI Selector correct to use single card and try flash the latest BIOS 1014 for your motherboard and did you tried installed the latest nForce 4 6.70 driver?

Lauwenmark78
10-27-05, 12:43 PM
- The SLI selector is correct. I also tried to force the "AI" SLI-related BIOS option to Single Card Mode instead of "Auto", just in case - no influence on the result;

- The BIOS is indeed revision 1014;

- The nforce4 chipset drivers are 6.70. Same result with the previous 6.66 ones, though.

I have to admit: I'm really clueless.

Lauwenmark78
10-28-05, 02:00 AM
I finally solved this - the conclusion was somewhat surprizing indeed.

The A8N-SLI Manual states that in Single Card Mode, it supports:

" - 1x any PCI Express x16 graphics card on the first slot (blue);
- 1x PCI Express x1 card on the second slot (black)."

So I wondered, could have I done something as stupid as plugging the card on the black slot ? I open the case and check: no, I'm plugged on the blue slot.

And then, I have a look at the last chapter of the book (Installing SLi-ready cards), which I only quickly browsed the first time, as I only have one card. Surprize ! According to the picture, the blue slot should be top topmost one - yet on my motherboard, it was the bottom one. So I swap my card on the top 16x slot, reboot, and it works.

So for whatever reason, the Mole² who built my motherboard reversed the blue and black PCI-E connector parts. Why ? No idea. Maybe I own a rare collector ? :)


²: Yes, moles are commonly used to build motherboards. It is rumored that Abit uses squirrels, though.

rewt
10-28-05, 05:01 PM
On my board the PCI-E x1 slot is shorter than the x8/x16 slots.

saturnotaku
10-28-05, 05:17 PM
On my board the PCI-E x1 slot is shorter than the x8/x16 slots.

He's not talking about the PCI-E x1 speed. He's talking about quanitiy, like when someone puts 2x512 MB to say they have 1 GB of RAM.

Lauwenmark78
10-28-05, 07:41 PM
On my board the PCI-E x1 slot is shorter than the x8/x16 slots.

It has nothing to do with the size of the physical connectors. On an SLI motherboard like the A8N, the secondary wide port works either at x1 (single mode) or x8 (SLI mode). This is because the nForce4 can distribute up to 19 PCI-E lanes to the PCI-E connectors (in single mode, they are distributed as 16-1-1-1, and in SLI as 8-8-1-1).

In short, because of the reversed color code, I was plugging my card into a connector that is 16 lanes wide, but with only one lane being active. And in fact, there is no way to make the secondary wide PCI-E connector work at x16, despite its the size of its physical connector - the most you can get is x8 (SLI mode).

Note that nothing prevents you to plug a PCI-E x1 card into a x16 slot.

What is more surprizing is that the 6600GT was able to work in a slot configured as a x1 one - it means that the NV43 (the core chip of the 6600) *can* take advantage of supplementary lanes provided in x8/x16 slots, but doesn't *require* them to work.

rewt
10-28-05, 11:57 PM
My point being that there is a dedicated slot for PCI-E x1 on my motherboard, and it is short slot. Your motherboard is reporting x1 when the video card is connected in the long slot, correct? Mine doesn't, is either x16 for single card, or x8 for SLi (x16 total).


And in fact, there is no way to make the secondary wide PCI-E connector work at x16, despite its the size of its physical connector - the most you can get is x8 (SLI mode).

PCI-E 32x is possible with the A8N-SLI32 board, but I doubt it makes any remarkable performance difference, if any at all.

Lauwenmark78
10-29-05, 05:34 AM
My point being that there is a dedicated slot for PCI-E x1 on my motherboard, and it is short slot. Your motherboard is reporting x1 when the video card is connected in the long slot, correct? Mine doesn't, is either x16 for single card, or x8 for SLi (x16 total).
Of course it doesn't - that's because in non-SLi mode, you plugged your card on the primary x16 slot, while I had mine plugged on the secondary one because of the connectors color mismatch. If you tried to plug a single card in the secondary (black) slot alone, you'd get the same result: a x16 capable bus running at x1. And when using the primary connector, I got the correct behavior: x16 speed on a x16 plug.


PCI-E 32x is possible with the A8N-SLI32 board, but I doubt it makes any remarkable performance difference, if any at all.
In single-mode, probably not, because no GFX card is currently made to take advantage of the increased bandwidth available.

Now, if it can allocate the PCI-E lanes as 16-16-1-1 in SLi mode, then it can probably provide some performance increase in that mode, with cards fully using the x16 bandwidth (and that are thus limited with the "ordinary" A8N to x8 in SLi).

Note that I was actually speaking about the "ordinary" A8N-SLi, not the "32" version.