Onboard better than discrete?!?

m25 · #1 (**permalink**) 11-21-2008, 04:20 AM

I'm not comparing a GeForce 8200 with a FX 5200, but it looks like in 3D software like 3DS Max and Blender, a heavily loaded scene responds faster on a PC with onboard graphics than one with a relatively powerful external card. I had a 260MB file with losa of trees and grass and on a GeForce 6150 it rotated much faster than on my 4670

. My drivers are fine and games run pretty well but 3D scenes look like a world apart.
The only explanation I can think of is that the data of the scene are stored in system memory instead of the VGA memory, so that despite being much more powerful, an external card still has to go pick the data from main memory while an onboard one has a much faster access to it,.. any one any idea?

**mpilchfamily** · #2 (**permalink**) 11-21-2008, 01:25 PM

Sounds logical to me.

Now if that is the case then maybe manufactures should start adding features to utilize the system memory.

Wait didn't they already do that and it flopped?

anticupidon · #3 (**permalink**) 11-21-2008, 04:15 PM

i'm speechless...

djgandy · #4 (**permalink**) 11-24-2008, 09:58 AM

You can see this effect in a lot of things, especially windows (mirc is one app I can think of with a lagged scrolling effect on discrete)

It's probably down to poor optimisation. 3DS Max is all CPU rendered AFAIR. Basically the memory transfer to the graphics card is probably being cut out with onboard graphics.

**mpilchfamily** · #5 (**permalink**) 11-24-2008, 02:16 PM

Wow i though 3DS was more GPU bound.

m25 · #6 (**permalink**) 11-24-2008, 04:09 PM

Quote:

Originally Posted by mpilchfamily

Wow i though 3DS was more GPU bound.

Just when you rotate the scene, everything else (rendering effects) is done by the CPU, and not only in 3DS, the same logic applies more or less to all such software.
Let's hope that CUDA and the new Catalyst drivers (followed of course by software implementation) will change things. Just think that a today's mediocre card can render like 5 frames of Crysis; would be nice if those cards could render 1 fps of a 5000 frame animation, that would take like 3 hours instead of 30 and you'd only need a $70 GPU instead of a new $700+ system for the sake of a good CPU that would still render slower.