Wednesday, August 13, 2008

Geforce accelerated PhysX

I always know PhysX hardware would fail, and of course it did.Physics processing core on a PCI interface? HELL NO.It ended up hoping to be purchased by some big companies as its not doing well, which nvidia eventually did.Nvidia purchasing PhysX promised acceleration using its own Geforce GPU using CUDA.Which is a good news to me, even i hate PhysX religiously and dont think GPU should be doing anything else other than churning out pixels during gaming.But who would complain when new features come knocking at your doorstep with a simple driver upgrade?
So i decided to give it a run,checking out its performance and experiencing physX capabilites. Come in at a hefty 100MB driver installation package, which include forceware 177.84 and physx driver 8.07,installation when well for me even though many reported problems.Even though GPU is the fastest component in your enitre PC, sharing physics and pixels crunching doesnt look like a good idea to me.

3Dmark Vantage
HIGH
No physX-6.86 steps , 100% cpu cycle
PhysX-103.57steps , 80% cpu cycle

15x performance against a dual core allendale with previous generation card is sure impressive for nvidia.But the cpu cycle is very troubling.Since this test is purely on physics caculation, and who take care off the physics? GPU. So why 80% cpu cycle?Rendering the simple low resolution planes flying around? Never. So 2 simple theories.GPU acclerated PhysX, which is currently done through CUDA has a high CPU overhead. Or Nvidia make BOTH cpu and gpu handle the physics caculation together to get a higher score,which is highly possible IF they have the capability to do so, since they are "VERY" honest for past few years...

UT3 max setting at 1680x1050
Heatray map
No physX-51fps AVG , 15second loading
PhysX-27fps AVG , 59second loading

Framerate took a big drop which is expected since pixels and physics is processed on my 1 and only 8800gt,but the loading time sure look depressing.PhysX create a constant irritating barrage of ice hail which in no way makes the experience more realistic.Noticed some extra destructible objects but still doesnt impress me at ALL.Tried the other 2 PhysX enabled maps in UT3 , nothing really impressive to make me come back for more.But PhysX promised something current CPU couldnt achieve, cloth stimulation.
So i downloaded a small little demo call nurien at its alpha stage.The cloth physics is extremely advance compare to current physics implemented in game with models' clothes moving according to the wearers' movement,although it still look rather unnatural.With the demo only able to run at 1024x768, the average frame rate is 35FPS and the loading is a hair-pulling 2 minutes.Of course one can argue its a alpha build,but performance sure dont look good at the moment.
Using your old graphics card in SLI to caculate PhysX seperatly may be a good idea, but with its not as rosy as nvidia have hope for.Firstly, i does not and will not buy a nvidia motherboard, since any NForce is technically inferior to its competitors in every aspect.Second, what PhysX currently offers doesnt worth the extra power consumption.Pushing my GPU to produce the most photo realistic visuals is my goal rather than extremely realistic physics, and i think many gamers have similar mindset.
Finally,I am not impressed by PhysX at all, and think physics should be caculated by CPU ,since most games barely utilised beyond the second core while quad core CPU have become mainstream.But i still support what nvidia is doing, as long as they keep it free of charge throughout its lifetime.

I dont think ths tornado worth 20 fps..
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Looking foward to physX accelerated boobs anyone?
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