I can run any game above 50 to 60 fps on max settings but i don't know why I get 30 fps on BF3, lowering the settings did not help a bit. My specs are:
Operating System:
Windows 8.1 Single Language 64-bit
CPU:
Intel Core i7 4790K @ 4.00GHz 30 °C
Haswell 22nm Technology
RAM:
8.00GB Single-Channel DDR3 @ 932MHz
Motherboard:
ASRock Z97 Pro4 (CPUSocket) 28 °C
Graphics:
BenQ RL2240H (1920x1080@60Hz)
4095MB NVIDIA GeForce GTX 970 (EVGA) 44 °C
I think it's because of Windows 8.1 or your RAM.
My Specs are:
CPU:AMD FX-6300 Six-Core
GPU:Nvidia GeForce GTX 650
RAM:8 GB
Monitor:1440x900@60Hz
I can play Maps like Metro with Maximum Settings on 60-70 Frames,but on Maps like Caspian Border (where's a lot of Lightning and stuff) I only have like 30-40 Frames.Only Medium to Low I can play everything on 60 Frames.Some weeks ago i had only 4 GB of RAM and couldn't even play Metro on Medium.
tl;dr:It's probably your RAM because this is the only thing that is a little Low on your Rig
