View Full Version : 7800 GT on PCI Express x8?

11-29-05, 09:51 AM
Just built the system in sig, any thought on why my graphic card only runs at PCI Express x8?
Mobo spec said both PCI Express slots are x16.

latest driver 81.95 for Graphic card
latest driver 6.70 for motherboard

any suggestion part from changing the PCI express slot since I already done that and both slot report back as PCI Express x8.

11-29-05, 10:04 AM
looks like although your motherboard has two physical x16 slots, it really has two x8 electrical slots. this is how most SLI boards (except for the new nforce4 SLI32 chipset) are. the chipset only provides so many connections/lanes for the PCIe bus, but there arent enough to run two x16 connections (requires 32 lanes, i believe nf4 sli usually has 20-24 lanes) so when you run SLI, it runs the two cards at x8.

if you are running one card, there should be an option in your BIOS that makes one slot x16 and the other one x2 or x4. i was looking at your mobo on newegg, and there seems to be no card slot like on the a8n-sli, so if you can change it to x16, then it will be in your BIOS.

if you dont find an option to change it, i wouldnt really worry about it. you wont really notice a performance difference between x8 and x16.

Redshirt #24
11-29-05, 10:40 AM
Check this page (http://www.pcper.com/article.php?aid=166&type=expert&pid=5). The relevant BIOS setting appears to be HT Width.

11-29-05, 05:16 PM
Thx for the reply, I've been away from my comp for the last 5 hrs.