Battlefield 3 Struggling to run on Full ultra?

Explosivx3

Honorable
Jul 3, 2013
46
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10,530
This summer I built a pc myself to play games at decent quality and good framerates. It has an i3 3220, 4gb Corsair Vengeance RAM and an HD 7770 1GB GHZ Edition, and my resolution is 1360x768.

Recently I bought BF3 and I noticed that it struggles to run on Full Ultra, the game starts to stutter badly after some time when It's rendering new environments or with lots of action. I got a bit worried and thought it could be because of the lack of RAM or the GPU not having enough bandwidth, so I downloaded MSI Afterburner and on ultra it can get to ~ 980mb of GPU Vram usage, and so I turned off AA and now it doesn't go above 930mb, making it run just fine. I'm asking if this is normal? Would getting another stick of RAM and doubling it to 8gb help at all?