HELP! In Witcher3 Nvidia Physics only uses CPU. My graphics cards are GTX Titan Black & GTX 750Ti for Physics.
Geforce driver version is 355.82 (Physics v. 09.10.0513).

Might I suggest you try the CD Projekt Red Witcher 3 Tech Support Forum? GOG didn't make The Witcher 3, CD Projekt Red did.

You SLI two Titans and a 750ti??? Is that possible? Also check if you have the little redistributable needed to run it.

You might also want to go through the Witcher 3 forums on GOG in case someone already reported this (and found a solution?)

http://www.gog.com/forum/the_witcher_3_wild_hunt

If not, then as Wishbone said, CDPR forums are your best bet.

What makes you think that he has two Titans? He only mentioned one Titan and one 750...

That's not SLI, 750Ti is just for PhysX.


Also, not sure about Witcher 3, but PhysX has various implementations, so it's not always using only GPU (even if you have nVidia GPU).

Right, I thought he had two Titans when he said ''my cards''. Sorry for the mistake.
But can you install two non identical GPU like that? I didn't know it was possible.

Sure, but as I said, the 2nd card can only be used for PhysX, not as a part of SLI.

edit: see this FAQ - http://www.geforce.com/hardware/technology/physx/faq

"Which graphics cards can accelerate NVIDIA PhysX?

All GeForce 8 series graphics cards and above with at least 256MB of local onboard graphics memory and at least 32 cores will be able to accelerate NVIDIA PhysX. If you intend to use an NVIDIA supported graphics card as a dedicated Physx card, the other graphics cards in the system must also use an NVIDIA GPU."

Wow didn't know that. Thanks for posting it! Very cool pro consumer of Nvidia not to require identical cards for that.

Given that the two cards operate completely independently of each other in that scenario, there is no reason for them to be identical, unlike with SLI.

Doesn't Witcher 3 use only the CPU for physics related stuff by default? I vaguely remember reading something along those lines.

Either way, with your main GPU you shouldn't have any performance problems, unless your CPU is complete crap. ( In which case, why would you install a Titan in an outdated PC? )

Major bug in W3 is W3.

One Titan Black for Graphix, one 750 Ti for Physics. Thanx! I will.