Hey guys

I have a 670 GTX and I really wanted to have hairworks turned on without killing my fps (I have other things on high and ultra, minus a few things like motion blur etc)

If you go into control panel and make Physx go through CPU, you'll have all the benefits of the feature without any loss on FPS. My CPU is an i5-3750k.

How are you going with the rest of the settings? Same exact card with an i7 even and sometimes it's barely doing 30.

Motion blur and blur are turned off.
AA and bloom are on.
Ambient Occlusion is SSAO.
Sharpening is at low, it can go high but I personally didn't like it. Either way, you're saving 1-2 frames probably.
Depth of field, chromatic aberration and vignetting is off.
Light shafts is on.

Hairworks on.
Number of background chars, Shadow, water quality, grass density, foliage visibility is high.
Terrain quality, texture quality and detail level is Ultra.

Foliage can go ultra, as can grass density but saves 1-2 fps again to get better stability at 30. Otherwise bumping a few more things will have it drop to 25 on occasions. So from there its just a matter of 30-stable or 25-30 fluctuations.

Hairworks is not using PhysX to work, so that wouldn't work - it uses DirectX 11 tessellation to accomplish it :)

https://developer.nvidia.com/hairworks

But in rendering.ini in TW3 subfolders somewhere under config/, you can try lowering the antialiasing on Hairworks from 8 to 4 or 2, maybe that helps!

somethign is using physx, from the GPU, i assume its hairworks but i still havent seen official word on this

As someone else said, HairWorks is not PhysX and since a couple of years ago, GPUs are far more powerful than when it comes to CPU to calculate physics if I recall right.

All you can do is either purchase a faster GPU*, wait for optimizations by patches, drivers or manually tweaking the game.

*I've been reading on a couple of hardware forums and apparently this game is extremely GPU bound.

New drivers for Kepler series

Unfortunately I don't think nVidia have gone public what exactly in the game is used by PhysX. Also, I don't know what your CPU or GPU is to answer your question theoretically.

The point is, use your CPU for Physx so you aren't burdening your GPU with all the work. Yes, the GPU is designed to do it but guess what, it has a million other things to do too. Save yourself the trouble and make it go through your CPU and your GPU can focus on doing more important things, like visuals.

Spread the work load where you can, Physx(and Gameworks) is one aspect.

If barely any PhysX is used in the game, I doubt it will make much of a difference anyway. If it is, then won't the CPU struggle more than the GPU even if it has other things to do? Granted, it's very GPU bound so I suppose in certain situations you might be right but have you really noticed a performance boost?

Witcher 3 don't even break 30% cpu usage on my old i7.
Even on the i5-2500K which is the minimum the game is supposed to accept there should be plenty of of power left to use.

Yes, that is why I posted it. Without it, I was not able to increase my settings and turn hairworks on, the 670GTX just can't do it all. The CPU won't struggle, these days CPUs are incredibly powerful and are not used to anywhere near their limit.

I have one friend with a 900 series card and he also noticed benefits to his frame rates that enabled him to increase graphical quality further with ini tweaks beyond the game settings.

Just give it a go, if you don't notice improvements to your frames, then fine, but I think everyone will find benefits.

Might be placebo but switching physx to cpu has helped me at least. Running without as many dips on the settings I actually want now.

How can you choose if Physx runs on your cpu or gpu?

Go into the Nvidia control panel or equivalent and there's a section of it's own. Under configure Surround, Physx.