So I was viewing the just announced Radeon cards, and I saw that 3DMark Firestrike score and I thought, maybe I need a new GPU or CPU. So I downloaded 3Dmark and tested it.
My score was 4453 with my AMD 955 BE and the Sapphire Radeon 7870 http://www.3dmark.com/3dm/1284446
Is that normal for my PC? Cause I find it very rare that I can only run games like FarCry3 on medium settings
Stick with your current card
Once mantle optimized games start shipping you will find that your card will perform beautifully.
I'm not sure why you can't run Far Cry 3 on medium setting. I have a 6870 and I can run Far Cry 3 on high-ultra in 1080p just fine. Even though I'm running an i7 950, I don't think that there is much of CPU bottleneck in your case.
That is great but, I really think there is a problem in my PC. And I don't know how to search for it/find it. I've seen people play Crysis 3 on medium settings with the same parts and no problem, while I can only play on the lowest settings
Download the latest drivers for your GPU, check your CPU usage while playing (90%+ probably means that it is bottle-necking your GPU), and keep in mind that this could be a problem for certain games that rely heavily on the CPU. And also make sure to pay attention to your temperatures.
This I expect you already did but try turning down some of the graphics filters and Anti aliasing down.
I did turn all the filters down, but how can I check for the usage?