
I believe I've run into a performance bottleneck on my computer and I need help pinpointing the cause.
The issue here revolves around antialiasing and smoke, specifically 4xMSAA. Whenever I use 4xMSAA or beyond, I get FPS drops whenever there's smoke on screen (sometimes when there's no smoke too). The screen gets rather smoky at times so gameplay can become noticeably choppy.
Now, when I bump down to 2xMSAA, everything is smooth. I still get the occasional FPS dip but for the most part, solid 60 fps.
This is all with V-Sync on. I can't play Doom 3 without V-Sync, there is too much screen tearing and it distracts me from enjoying the graphics. I've tried Adaptive and Standard V-Sync.
Here is something interesting though. If I enable "Triple Buffering" in my NVIDIA Control Panel for Doom 3, my FPS smooths out with 4xMSAA and the game is much more playable. The problem is, I get screen tearing. More specifically, it's one line that hangs on my screen and is really noticeable. The odd thing is, I've used Triple Buffering with the original Doom 3 and did not encounter this issue.
So my computer is having trouble making that jump from 2xMSAA to 4xMSAA and I'm trying to understand why. Here are my specs:
E8600 @ 4.0 GHz
4GB DDR2-800
GTX 650 Ti
Latest video drivers and DirectX installed
Not state of the art but should be able to run Doom 3 BFG with 4xMSAA smoothly (anyone disagree?). I've tried overlocking my video card's memory to make up for the weak bandwidth but it did not help at all. So I do not believe it's a memory bandwidth issue. It's not my CPU because antialiasing is relying on my graphics card, correct? It's not my system memory, 4GB should be enough for Doom. So what else could it be?
I've dealt with this issue since Doom 3 2004. Anything past 2xMSAA gave me FPS drops. But here is what bothers me. I've read all this stuff about how Doom 3 BFG runs more efficiently and how it's smoother and faster cause of com_smp 1 and streamlined id Tech 5 code and so on. Well can anyone give me an example on where the performance improvements are? It's certainly not affected the efficiency at which smoke particles are rendered nor has it affected antialiasing performance.
I just feel like I wasted 30 bucks. I thought Doom 3 BFG would run better on my computer than vanilla Doom 3 but I still get the same FPS drops in the same situations and I can't manage to understand why. Is multisample antialiasing really that taxing with this game?
EDIT ::
So really I could solve my problem by figuring out how to enable Triple Buffering without screen tearing. There's a plethora of options in NVIDIA Inspector to tinkle with, I suspect the answer is in there.
Also, does anyone know how to enable SGSSAA with this game? I've never got it working with Doom 3. The F0C1 compatibility does nothing, wondering if Sparse Grid is even possible. I can get regular SSAA to work but performance is atrocious and everything is blurry.
Finally, anyone have any insight on the r_lodBias setting, specifically why it's defaulted to "0.5"?