Member Avatar for Salo1971

Can some advise me when running the above graphics cards in SLI Mode should the Bus PCI Express be x8 ? in the system information panel. Or do i have to go into the bios to set this to x 16. SLI is Enabled.

Forceware:163.71
Memory 256MG
Bios 5.
IRQ 18
Bus PCI Express x 8?

Or is their any other settings i need to tweak to get the best performance my Power supply is 550w

Many Thanks sal any help would be great

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Dani AI

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Good point from — that observed change in the reported PCIe link is not a BIOS bug but how many SLI setups present themselves. A few practical checks and quick fixes that are still useful years later:

  • Verify physical and BIOS things first: consult the motherboard manual for the exact SLI slot order, make sure the SLI bridge is seated, both cards are in the correct slots, and BIOS/PCI-E/PEG options are set to Auto or the board-recommended setting. Update motherboard chipset drivers and the BIOS if updates exist for SLI handling.

  • Confirm with tools and testing: use GPU-Z to read the Bus Interface (Link Width and Link Speed) and HWiNFO for slot details. Run a real-world benchmark or a demanding game to compare single-card vs SLI scaling — that tells you whether the lane configuration is actually limiting performance. Monitor temperatures and clock speeds while testing.

  • Power, stability, and tuning: ensure each card has its proper PCIe power leads and that the PSU can supply clean +12V current on the rails. Avoid cheap Molex-to-PCIe hacks where possible. If you see instability, try one card at a time to isolate the issue. For best results keep drivers (NVIDIA control panel/Stereo/SLI profiles) and OS power settings tuned for high performance.

These steps will confirm the setup is correct and reveal if anything else (power, cooling, drivers, CPU bottleneck) is limiting performance rather than the reported PCIe link width.

GPU-Z
HWiNFO

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Member Avatar for Chaky

That is normal behaviour.

When there is a single VGA, the PCI-E works at x16 mode, and in SLI mode it is 2x8. No tweaking possible.

Member Avatar for Salo1971

Thanks mate

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