separate 3d and 2d clock settings, how come?

bboysil

Distinguished
Oct 5, 2006
158
0
18,680
I have a tool which let's me OC my GPU and VRAM on my Gainward 7600GT

. but on the GPU tab i have two options: 3d clock and 2d clock and i can set them separatly.

How come?

Does the GPU switch automaticly beteween the two clocks depending on the type of work or are thare two parts of the GPU that get separate clocks?
 

mkaibear

Distinguished
Sep 5, 2006
678
0
18,990
It does switch between the two automatically. I know on my Ti4200 that they were separate (because the 3d part failed whilst the 2d part worked, so I could use windows but not run any games), I dunno what the newer architectures do. I suspect they're all integrated.
 

HDDFreak

Distinguished
Feb 14, 2006
149
0
18,680
I believe that's because it's unnecessary to overclock a card while in 2D, thus increasing heat (and possibly fan speed). Why bother consuming that little bit more power and making that little bit more heat when its unnecessary?
 
the ti4200 didn't support dynamic frequency switching; you need a FX at least to make use of that.

Note: it is also accessible through Nvidia's driver when using the coolbits registry hack. It is disabled by default on desktop GPUs, but enabled on mobile ones.

Geforce4 and older: no clock switching (neither CPU nor Video RAM)
GeforceFX: GPU switching
Geforce6: GPU switching
Geforce7: GPU and VRAM switching (? please confirm)

The card detects if you use 3D elements (textures, triangles) and switches to its 3D clock in under 3 seconds (this happens when using Direct3D as a video output too) then switches back to 2D clock 5 seconds (on average) after no more 3D elements are displayed.