pcie 3 slower than 2??

[james_2k]

Hi guys,

got a quick question,

when i run 3dmark 11 on the new setup with pcie 2 selected. i get roughly the same gpu performance as my old i7 with the same gpu.

but if i enable gen 3 pcie in the bios and so use pcie 3.0 i get lower performance. which translates to around 1500 graphics points. i tried reinstalling the driver, but i cant think why it would run slower with the newer pcie version,

any ideas anyone?

 

[andybird123]

you have your CPU clocked very high, this could indicate some instability creeping in when using pcie 3.0

I had the same on my 3930k, I have to drop from 4.6 to 4.5 when enabling pcie 3.0 (as I didn't want to try bumping any voltages any higher than I already had them)

extra bandwidth means extra stress on the CPU

I always do memory first, then set pcie3.0, then work on the CPU clock - once you get the first 2 stable, you know that you only have to worry about the CPU clock, otherwise you are trying to change too many variables trying to do all 3 together (or you are making a previously "known good" OC in to an unstable one)

 

[james_2k]

Hmm. Ok I'll try bumping it down a bit and retest cheers

 

[Kaapstad]

PCI-E 3 puts more strain on the CPU so it might be something to do with that and overclocking the CPU.

Try turning off any of the PCI-E slots you are not using, iirc your board has got four little white switches to do this.

On X79 I can use PCI-E 3.0 with my Titans but for a 4 card setup when benching I find it a lot more stable to use PCI-E 2.0 as the extra strain on the CPU can cause problems.

Having said that though single or two cards work fine with PCI-E 3.0

 

[james_2k]

ok weirdness is continuing.

i switched to bios two. which is standard. and just applied my overclock settings.

now its running faster than pcie 2.

i just wish i knew what it was that slowed it down. im not a fan of going through the bios testing every single one!!

 

[james_2k]

must have been a bios setting. cleared cmos and setup the same overclock.

gained 300 solid points over the old pc config. not huge but still.

so theres your answer kaap. 300 graphics points more

 

[Kaapstad]

must have been a bios setting. cleared cmos and setup the same overclock.

gained 300 solid points over the old pc config. not huge but still.

so theres your answer kaap. 300 graphics points more

That's a pretty good increase.