View Full Version : P45 16x/8x question

04-29-09, 12:27 PM
Hey guys is there a way to run a second video card (for physx) in a P45 while keeping the primary slot at 16x? cpu-z and gpu-z shows them running at 16x and 8x (not possible, right?) but the nv cp shows the cards at 8x/8x. Is it possible to get 16x/1x or something?

04-29-09, 12:33 PM
The P45 chipset splits the bandwidth equally when multiple cards are installed into the 16x slots. I'd remove the PhysX card ASAP. :(

04-29-09, 01:01 PM
That hurts but its a worthy trade off. Getting rid of the asus maximus (x38) was the best thing I have done for my sys in a very long time. I cant believe I used that pos for so long. Thanks for the quick reply, I'll wank it asap. It's to bad my little brother runs a P35 so he cant use it either:(

Edit- Still weird that cpuz and gpuz show the 295 running at 16x and the 9600 at 8x. The nv cp was showing 8x for each 295 (and 9600) so I was reading that one wrong.

04-29-09, 02:24 PM
PCI-E 2.0 has twice the data rate of PCI-E 1.1 so in a way 8x on PCI-E 2.0 is the same as 16x on PCI-E 1.1.


Honestly, I'd leave the Physx card in there since it will help a LOT with Physx games like Cryostasis. I don't think there was any real bottleneck with PCI-E 1.1 so I doubt you're losing any performance by running at the equivalent of PCI-E x16 on a 1.1 slot. There is probably a performance loss in SLI or Crossfire configurations, but since your Physx card doesn't need to communicate with your main GPU it shouldn't slow anything down.

If you aren't playing any Physx games right now though, I'd take it out to save some heat and power.

04-29-09, 02:26 PM
Don't worry about it - an 8x PCI-E 2.0 slot is enough bandwidth for a single card.

There is only really problems if you are running two cards (which end up saturating the bus because they send information back and forth) and on PCI-E 1.0

04-29-09, 04:54 PM
PCI-E 2.0 has twice the data rate of PCI-E 1.1 so in a way 8x on PCI-E 2.0 is the same as 16x on PCI-E 1.1.

Good point. PCI E 1.1 has been proven not to bottleneck the GTX 280 so 8x PCIE 2.0 shouldn't either!

04-29-09, 06:49 PM
Thanks guys but its a lot better without the 9600 in there. It was chuggin quite a bit running at 8x pcie which i think my oc doesn't help. I mean at the clocks i run it at its like having two GTX280s. Even physx games like cryostasis and especially sacred 2 are running much-much better now