Game lags during playthrough

[Stimpak]

As requested, I'm making a Tech Support thread on this issue for further reference.

ORIGINAL: Stimpak

Sadly, I must report that the lag is back with a vengeance.

It kicks in about half an hour into a game now, and paying attention to the task manager I see the game's memory consumption rapidly jump from 450 MB to 501 MB. An action phase becomes almost unbearable to watch as the fx animations take 3 times longer, the map movement that is supposed to be smooth becomes choppy and delayed, and the computer running the game calculations just seems to give up.

Keep in mind, only my FPRS.exe experiences this lag. Other programs I may have open simultaneously do not suffer the same slow down.
This has persisted into the 2.0.11s release, but it seems that no one else has my problems. I'm at a loss for what to do.

This issue has persisted since 2.0.10bs. It's really made an otherwise excellent game mostly unplayable. What concerns me is that I appear to be the only user to suffer from this.

Some relevant information:
Operating System: Windows 7 Home Premium 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_ldr.161007-0600)
Processor: Intel(R) Core(TM) i5-3570K CPU @ 3.40GHz (4 CPUs), ~3.4GHz
Memory: 16384MB RAM
Available OS Memory: 16328MB RAM
Page File: 8531MB used, 24121MB available
DirectX Version: DirectX 11
Card name: NVIDIA GeForce GTX 660

[CapnDarwin]

Stimpak, Can you post us a dxDiag info dump as well? That will give us a deeper look at what is also running in the background.

Thanks.

[CapnDarwin]

Only one thing looked odd from the directx diag. You screen DPI was at 102%. Not sure that would cause a problem, but it's a starting point. It shows a wireless mouse. Try to change the surface the mouse sits on. I've had lag and slow down when my optical mouse was on a surface the caused jitter. That floods the message queue and slows the game to a crawl. Next we need to see what is running in your background during the game. Can you get a screen cap of task manager?

Thanks.