MW2 Framerate Issue

So I tried to start playing Call of Duty: Modern Warfare 2 single player, but as soon as I get into the part where I can control my character the frame rate dips to single digits and the audio gets choppy. The opening menu and the opening movie run fine, it's just once I get in-game that problems emerge.

I tried troubleshooting all the usual suspects: turned down settings such as lowering resolution and graphics quality, checked/updated my drivers, turned off all other programs, used fraps to see what my actual frame rate was (9-10 fps avg), etc. That didn't work. So I started up Windows Task Manager, called up the CPU/RAM activity monitor and started up the game to check whether my CPU was maxing out. The CPU was barely at 50% even while I was lagging out. Though this gave me the opportunity to notice that while I was alt-tabbed out of the game that the audio was now fine. I tabbed back into the game, but the audio became choppy again. In addition I also noticed that when I was facing a "less graphically busy" part of the game (ie. a wall vs. a group of soldiers playing basketball) my fps bumped up to ~30 and the audio got better.

This lead me to think that it was my graphics card's fault, so I opened up the Nvidia control panel and turned down/adjusted a number of the settings for MW2. That still didn't work.

Out of fear that I might have done something or gotten some sort of virus without my knowledge I started up a couple of my other games to see how they were performing. Borderlands, Crysis (~40 fps, in fact), Team Fortress 2 and Left 4 Dead all run fine. So it is exclusively a problem with MW2.

So, to summarize, there is something about my graphics card that is failing to work with MW2, and MW2 exclusively. Any suggestions on what I could do here would be appreciated. Thanks.

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Graphics Card: Nvidia GeForce 8800GT
CPU: Intel(R) Core2 Quad CPU Q9300 @ 2.50 GHz
RAM: 6.00 GB
OS: 64-bit Vista Home Premium
Current Mode: 1680 x 1050 (32 bit) (60Hz)

May be time for a new video card, not sure. I think the 8600 or 8800 is the minimum for the game.

Crysis isn't doing 40s at that resolution on that computer unless it's all on low/some medium. Turn off both the AA and AF and lower the settings; that's all I can recommend. Your GPU isn't that powerful anymore and it's a brand new game.

Ok, impossible as it may seem, I actually found the problem. Apparently I have a bad RAM slot. I happen to have 4 slots and only 3 sticks, so I just switched one stick around and it's all sunshine and rainbows.

I was noticing some odd performance glitches that I thought had to do with my graphics card. For example, after all this trouble started I was blue screening on a hard boot up (turning the machine on after being completely off), but it would do a RAM dump, restart itself and be perfectly fine. When I actually logged in, Vista being the inapt helper that it is tells me that I have had an nVidia driver issue. This was especially odd because when I did soft restarts (just restarted the machine, didn't turn it off) no blue screen occurred.

I finally became suspicious of my RAM because I was absolutely sure that I had everything right with my graphics card (assuming it just wasnt' broken). So the fact that my machine needed to do a RAM dump was just something I thought I'd look into. I first checked for bad memory sticks by removing one at a time, it didn't really fix my problem until I took out one particular stick. This left me with only 4GB of RAM, and I being the greedy guy that I am made my self a hopeful bet that it was the slot and not the stick. Turned out to be a good bet because everything is fine now.

Hopefully these long elaborate posts aren't too annoying to the people reading, but I was just trying to make sure that you all knew what I had tried and how I fixed the problem.

So, to summarize: if you get weird graphical slowdowns on your highest end programs and you are absolutely sure that your graphics card is up to the job, among the many things you might want to try, check your RAM.

Thanks for the help.