Would a 4890 make a difference?

The extra memory will help you out run smoother at that higher resolution. Are you running it at highest graphics?

Also, have you tried playing any other graphics intensive games at that res? It could just be MW2 (but I doubt it). Give the Far Cry 2 or Crysis demo a shot.

One last thing, I love your avatar; Metalocalypse is AWESOME!

Some benchmarks indicate around 10-25% increase in performance, plus if you OC the 4890 it will be even higher than that.

4890's are cheap nowadays since the 58xx line is out anyways.

Just outta curiosity, what is your average FPS in MW2 with that card? And what's the lowest that you've seen it go to?

Yeah, the 4890 1GB would provide a smoother experience and should allow you to add AA at 1920x1200.
But it's a tough decision whether or not to drop the extra cash for maybe a 10-15% upgrade in performance.

It's probably just a result of the 512M. I had similar issues with lag in memory intensive games. The extra memory of the 4890 makes a big difference, not to mention its all around faster. Pretty decent upgrade I'd say, although might just want to save up some more and go five series. 4890's are cheap now though.

My old faulty 4890 (when it worked) beasted COD4 at 1920x1080 everything on high, 4x AA and AF maxed out.

I got consistently around 60-80 fps.

Don't have MW2 yet, but they can't be THAT much different.

I can run MW2 fully maxed w/ AA at 1080p with my 1gb 4890 with minimum stutter, so you should be alright

thats strange.
my 4870 at times with everything maxed out gets 100+ frames
and i always run at 1920 x 1080. maybe the extra memory does make a
difference.

Yeah, I hate getting shorted on vRAM lol. My 320mb suffers in terms of smoothness and playability when compared to the 640mb version of the 8800GTS, especially with AA and high res textures.

Xfire that thing. Youll run like a glove

At least there's some repeated results here. I would like to get the take of someone that has a 512mb 4870 and how they do with MW2 and 19x12.

All I know is that when the battle scenes got extra hairy, at 1920x1200 my 4870 would stutter and sometimes give me a ~2 sec slideshow. It was unbearable in the airfield level towards the end.

I don't thing COD MW2 is that memory intensive. I remember back when 512MB came out there was only one game were the card would fail and that was @ 1600p. It could be some driver problem. With COD4 is had a bit of a problem with one my my card and it was felling a bit choppy but the fps were always over 80fps so maybe you can set the fps to stay at 60?

The 4890 is a pretty reasonable upgrade from a 4870 mainly because it comes stock with 1gb gddr5 and is a MONSTER overclocker. I have both of mine running at 950/1150 and they don't even break a sweat. When I played MW2 with mine (before I got the second) it played it perfectly

I was once in nearly your exact situation, even had a visiontek 4870 512MB, lol. I upgraded to a 4890 and while most say it's a minimal performance increase, for me it felt like night and day. CoD4 could run MTFO 4xAA(8x if I felt frisky), Crysis was on the verge of playable @ v.high 4x AA, and very playable @ all high 4x AA, FO3 became 110% playable when it was not previously. STALKER:SoC stopped w/ it's hiccuping on large maps w/ long view distance, Clear Sky w/ tweaking was playable. I can go on and on.

It was definitely worth it to me.

Only other cards I'd possibly recommend would be a 4850X2 2GB or 5850, either of which are probably out of budget. A 5770 would probably do, especially after a decent OC.