Far Cry 3 under 45 FPS on ultra with 7950

I say it's normal fry cry 3 is very demanding game lower your settings to get higher fps.

Under video options at SSAO method choose HDAO. This fixes the problem for some.
As I unerstand it you choose HDAO if you have an AMD card and HBAO if you have a Nvidia card. SSAO are giving perfomance hits and have known issues with shadow effects.

Also, an incredibly good way to jack your fps in FC3 by 10-15fps and actually make the game look much nicer is to disable PostFX. From what I understand, PostFX was put in the game due to some sort of console limitation since the game was made for consoles, and you can only set it to Low in your graphics setting. However, if you go into your gameprofile.cfg file with notepad, you can set PostFX=False and it will fully disable it. It makes the game look great, because it gets rid of motion blur, has somewhat of an anti-aliasing affect (no idea why PostFX LOWERS AA), and gets rid of the blur on scenery in the far distance. You will immediately notice a difference if you look at a mountain in the distance, which is now clear instead of blurred, and it increases your fps by a ton! Give it a try.

That's some really good advice. I don't think I will disable it as you say but I will turn it the lowest it can go.

Just for reference, with my GTX 660Ti OCed, I run Far Cry 3 on the Ultra preset, w/HBAO, Extreme Brush rendering, 2xMSAA, and I get anywhere from 45-65FPS. On average I get 55FPS. And the 660Ti and the 7950 are pretty much equals, so we should get around the same FPS using the same settings. You should be able to use more MSAA than me though, so they say.

You know, it might be that you have MSAA set too high. I know if I set MSAA to 4x's I only get like 35-40FPS. This may be why you are experiencing these problems. What did you have MSAA set to? I'm curious to know?

I also find Far Cry 3 to be way more glitchy that most other games I play. Sometimes the graphics will completely just go crazy and you can't see anything, sometimes I'll get this shading on the screen that never goes away, sometimes the dirt roads will flicker, sometimes the gameplay is just rough as hell. Of course all of these things only happen about 1% of the time, so it's still not a big deal. But it does happen kind of a lot.

you have msi twinfrz 7950, one of the best overclocking gpu brand and you havent oc'd?

thats like buying an h110 to an non-k i5-3570

I noticed that the biggest frame killer was Post-processing anywhere above medium level. Either it's just poorly optimized or too much visual stuff crammed into one setting. This was way back on AMD HD 7970 and HD 6970 with the release drivers though.

You should also download and install the latest 13.3 Beta3 drivers for AMD. Believe it or not, 3 months after release these drivers increase performance in Far Cry 3. Tested for myself just the day before yesterday.