Dedicated Physx Bandwidth issue? on P5q deluxe PCIE 1.1 x4 GTX460?

The 4X is big enough for PhysX handling, it's never going to be used to it's maximum....
Even if you were to use 2X SLI (Which I doubt if this board can do) or CF on the board plus the 460 to handle PhysX, it's not going to effect the total bandwidth allotted to the other 2X Cards......

What is your main GPU? I'd probably go with something more along the lines of a 9800GT.

PhysX doesn't need much.

I use a GT 240 on the Asus P7P55D Pro PCIe 1.1 4x slot. Works great. Usage is maxed out at around 80% due to the bandwidth. That 460 will probably be more like 50% unfortunately.

After playing Mirror's Edge, Batman, Cryostasis, Metro 2033, and Mafia 2, the only time I noticed that PhysX caused a frame stutter was a single moment in Mafia 2 where a building explodes. Otherwise, no issues to report - even when I was doing mad burnouts with a muscle car and there was a ton of smoke, or in Batman when there's a lot of cloth PhsyX along with some nice smoke PhysX.

I've been able to use the High PhysX settings as well.

@Wolfram23
Sounds like good results. What is your main video card? And are you running at 1920x1080? The reason I might try the gtx460 is the shader count for future upgrades. If it's only going to be loaded 50% in this rig, and I get the same performance you do, then that would sufice. Hopefully in 5 years I would still be able to use it just for physx in a x16 slot. Also I notice the price just dropped a little so hopefully down the road it will cost less than it does now.

If your buying soon, you might consider the gts 450, has 192 cuda cores, 120.00 , 95.00 AR http://www.newegg.com/Product/Product.aspx?Item=N82E168...

My main GPU is crossfire 5850s, and yes playing at 1920x1080.

I still don't think the 460 is the best choice, just too pricey for what it's going to give back as a PhysX card. The 450 notty suggests is a good choice, or even just a GTS250 or 260. But anyway, do what you want. I would just hate for you to regret buying a $220 GPU so you can experience PhysX is like 5 games lol. I really hope that either PhysX catches on, or even better, developers start using open source GPU acceleration.

@wolfram, Thanks a lot for your input. I got a deal at Fry's electronics for the gtx460/768mb for $129 after rebate. I'm going to use that for my main card until the 28nm cards come out next year. I'm using my 9600gt for physx until then. I got a 5fps increase in Mafia2 1920x1080 high apex with this config. The downside is that's only going from 17fps to 22fps. With cloth off I got 33fps. I'm running with an e8400 right now and I think that might be the reason of the slow fps in Mafia2. I noticed that both cores run around 96% when benchmarking. I've got a qx9650 sitting in a box in the cupboard that I'm going to install in a few days and see if that helps. I hope it's more than just 5 fps. Now that we are pretty much done with the Crysis fandango they come out with Mafia 2. I guess that's what makes us by the stuff.

@Wolfram I agree totally with the open source suggestion. Didn't Crysis use their own Physics system? Or was it Far Cry 1? FC1 looks way better than FC2 in my opinion and they don't depend on Nvidia physx. Honestly I'm only mildly impressed with Physx in Mafia2 but like I said, I just want to future proof my system. Like that's even possible with Pc's any way.

Well most graphics engines have their own physics in them, but currently PhysX is the only one to allow for GPU acceleration which adds a bit of advanced physics that would have a tough time running off the CPU - like the cloth effects, smoke particles, advanced water physics and they also add a little eye candy like more particles and chunks fall off things that you shoot.

I know ATI has been promoting Bullet physics engine which apparently can use either OpenCL or Direct Compute - I forget which - but it should allow GPU acceleration on ATI or NV cards. The problem is, it hasn't really caught on.