Installing a dedicated PhysX GPU

[Vargur]

I bought and sucessfully installed a GTX560 today, and want to use the old GTS250 as a dedicated card for PhysX. Problem is, each time I plug it in and start up, my monitor isn't displaying anything, only the status light flickering as if it were shutdown.

[vesseblah]

Best for you is to not use the second card at all, as the amount of games using PhysX can be counted with fingers of one hand and offloading the physics processing to a much weaker card than the GPU is will in most cases only lower your framerate, not improve it.

I know this will not solve your immediate problem, but it is better long term solution.

[OhpUldum]

The immediate problem could be due to your power supply not having enough power to power on the display with two cards present.

[Vargur]

The immediate problem could be due to your power supply not having enough power to power on the display with two cards present.

I have a 650W Sirtec, should be enough. Maybe it was the connectors.. The PSU has 2 connectors for GPUs, and I used them both for the 560, because the card has 2 power slots. o_O
So I used extensions for the 250.

[OhpUldum]

Yeah the 560 will easily draw more power than the GTS250. I stand by it still being a power draw issue. A lot more concerns power than just what the retail box says it can supply. It could easily only put out a continuous 400W with a peak of 650W.

Even still Vess hit the nail on the head with using the GTS250 as a dedicated PhysX card, there just really isn't a point. You would more than likely end up bottlenecking the 560 if you did it.

[Deleted]

Yeah but the PC should boot up with both installed shouldn't it?
Are you sure you have all power connections hooked up, and you're not SLI'ing them (does the GTX 250 even have SLI support?)

[Vargur]

Don't see how the performance wouldn't improve with a dedicated PhysX. The GTS250 is an amazing GPU for its price. I only replaced it for the lack of DX11.

[Deleted]

Don't see how the performance wouldn't improve with a dedicated PhysX. The GTS250 is an amazing GPU for its price. I only replaced it for the lack of DX11.

Because the 560 is plenty powerfull on it's own, while the 250 isn't. The way I understand it, the 560 will have to wait for the 250 to finish it's calculations, which is bad.

There are virtually no games that use PhysX anyway. I saw the guy from motherboards.org going crazy on his BF3 video while he was inside the metro station and he saw particles flying off the fire. "LOOK AT THAT, PHYSX". The hell no, my 6950 does exactly the same.

[vesseblah]

Don't see how the performance wouldn't improve with a dedicated PhysX.

Simplified explanation with imaginary numbers that only illustrate a point, not resemble real benchmark:

case1 with physx disabled:
-game draws screen into primary gpu at rate of 100fps which is the maximum the card can draw with no physics handling at all
-> final fps is 100 with physx disabled

case2 with dedicated crap card:
-game sends physics drawing information to dedicated card which calculates PhysX at the rate of 40fps
-game draws screen into primary gpu at the rate of 40fps (the best the physics card can do)
-> final fps is 40 with physx enabled

case3 with physx enabled without dedicated card:
-game sends physics and normal 3d to gpu... GPU time is split to half: physics is calculated at 50fps and normal drawing is done at 50fps
-> final fps is 50 with physx enabled