16x+16x PCI-E vs 8x+8x and 16x+4x, does anyone have comparisons ?

Vogon · 19 Sep 2007 at 21:09

Links to articles, or knowledge, both appreciated

I am interested in what (if any) difference there is.
Also dual 16x is theoretically the best, but which of the other 2 would be second best ?

Thanks

Tee Hee Johnson · 20 Sep 2007 at 09:39

i know on my motherboard when in sli both my pcie slots run at 8x instead of 16... asus released one that managed to keep both slots at 16x when in sli

i looked into it with a wee upgrade plan... but the benchmarks showed VERY little in difference... which i thought was weird...

Vogon · 20 Sep 2007 at 09:48

When you consider right at the end of AGP, even the bandwith of 8x AGP was never fully used, it doesn't suprise me.
Thats why I asked about this, as I feel it might be the same scenario.
If you want a crossfire board, the forthcoming X38 chipset offers dual 16x, but current boards are either 8+8 or 16+4, I dont know if either of those is better than the other even :confused:

Thats why I was hoping someone could enlighten me

RaiderX · 20 Sep 2007 at 10:12

the 680i boards run dual 16x PCIe slots that stay at 16x in SLI, the 650i and all other previous SLI chipsets have the SLI card that changes the slots to 8x each when in SLI, the intel boards with Dual PCIe16x slots have 1 16x and 1 4x, the new X38/48 boards are the first crossfire boards with dual 16x and also introduce quad crossfire where it has 4x PCIe 16 and they run at 8x when quad crossfire is enabled

J1nxy · 20 Sep 2007 at 11:00

RaiderX said:
the 680i boards run dual 16x PCIe slots that stay at 16x in SLI, the 650i and all other previous SLI chipsets have the SLI card that changes the slots to 8x each when in SLI, the intel boards with Dual PCIe16x slots have 1 16x and 1 4x, the new X38/48 boards are the first crossfire boards with dual 16x and also introduce quad crossfire where it has 4x PCIe 16 and they run at 8x when quad crossfire is enabled

Almost right the 975 provides 2 8x slots when in crossfire.

pastymuncher · 20 Sep 2007 at 11:54

When i was on AMD rigs i had a socket 754 Epox 8NPA-Sli with two 8x pci-e lanes both occupied by overclocked BFG 7800GT OC's. The rest of the rig was a 3700+ @2.8ghz and 2Gb DDR. I then moved up to 939 with a Abit AN8-32X with two 16x pci-e lanes and a 4000+ @2.8ghz. Everything else in the rig was exactly the same. Now while i admit that a 7800gt probably would'nt max out the pci-e lanes i saw absolutley no difference at all. It may be different with a pair of 880GTX/Ultras as i believe they require a 16x lane to work although i have heard of them working in a 8x lane.