I heard my second link stopped working.
Here is the link again with copied and pasted info:
https://battlelog.battlefield.com/bf3/forum/threadview/2832654489840320059/
"I know a lot of BF3 players wonder why there performance can sometimes suffer, so here's a way to figure out whether your Processor (CPU) or your Video Card (GPU) is the problem.
I completely forgot about this nifty console command back in the BETA, but I came across it today again and I figured I would share it.
So lets say your experiencing FPS drops at random, and can't figure out what the problem is. Here's a possible solution:
1. Open up the console command by pressing the "~" key, which can be found to the left of the "1" key on almost all keyboards.
2. A small box will appear in the left top corner of your screen. In the Box type the following command exactly as I have it here:
Render.PerfOverlayVisible 1
After typing it, press enter and close the console command box by pressing "~".
3. In the bottom left corner of your screen, a small graph will appear, it will have both a yellow and green line inside it. These are color coded. The yellow line is your CPU performance and the green line is your GPU performance.
4. How does this help spot hardware issues? Pay attention to which line often dips lower than the other.
If the yellow line is below the green line, either consistently or at random, it means your GPU is holding your performance back and lowering some settings could help or buying a new GPU alltogether.
If the green line is below the yellow line, it means your CPU is holding you back and you should probably play on smaller servers or purchase a new CPU.
So to recap:
Yellow line BELOW Green line = GPU Bottleneck
Green line BELOW Yellow line = CPU Bottleneck
NOTE: To disable the command and take the graph off your screen open up the console command again by pressing "~" and type the following:
Render.PerfOverlayVisible 0
Press enter and close the console command. "