Does Doom opengl render actually use the gpu?

[ibm5155]

Yes, I'm asking that, it sounds really dumb, but I'm kind confused, that, it looks like most of the things rendered are not actually rendered by the gpu itself :s

So wtf are you saying, I was testing to over/under clock my gpu and see how much difference it would made on games,
I noted on grid 2 that the lowest gpu/mem frequency (385/560MHz) I got 15fps while in 775/1125MHz I got 32fps (on ultra settings and on max resolution), and then, I decided to test gzdoom/zandronum opengl render, and, the result was weird, I got no difference on the two clock tests, (385 vs 775 MHz), I tested FrozenT (a big open area map) and Hocus Pocus (with some 3D models and dynamic lights)...
The weird is, why I don't get any fps difference betw 385 and 775MHz but I get when I change the screen resolution? :s

and the weirdest is when I downclock the processor I got a huge fps drop, so, is the opengl render a kind of 32bits software render? :S

edit:also, the same as wolf the new order, i got 35fps on lower clock and 50 on higher clock

[Torr Samaho]

Yes, I'm asking that, it sounds really dumb, but I'm kind confused, that, it looks like most of the things rendered are not actually rendered by the gpu itself :s

The GPU is rendering everything you see. Since Doom wasn't designed with GPU rendering in mind, the way the CPU feeds the GPU is not terribly efficient though. In your case, the GPU simply seems to be fast enough to handle all drawing calls the CPU can come up with, i.e. the CPU is the bottleneck for you, not the GPU.

[ibm5155]

"the GPU simply seems to be fast enough to handle all drawing calls the CPU can come up with, i.e. the CPU is the bottleneck for you, not the GPU. "

So, it's like software render, the processor make a buffer, process all the scene, and send that buffer to the gpu memory right? ahm so what does the gpu draw? fog,3D floors,dynamic lights? or even that stuff are processed by the processor D:

if it's true, then it would explain why touching the gpu clock didn't made any effect but touching the processor clock made a huge effect...

well I don't think that the core i7 3635QM is slow here, but, it's a generic processor, ofc a gpu is much better to process certain datas... (but I'll not blame the render, maybe it's just how doom was made, there's no way to make it work on gpu with id tech 1 :s)

[Torr Samaho]

So, it's like software render, the processor make a buffer, process all the scene, and send that buffer to the gpu memory right?

No. To put it oversimplified, the CPU generates a list of triangles in 3D with texture information and sends that to the GPU. The GPU then renders a 2D projection of the 3D scene described by the triangles.