The "do ok" part is relative. As long as it doesn't stutter yes, it's playable, but that means just flying around and learning the new FM and aircraft for now. That's why i stressed this part a lot during my previous post.
3GB is a bit of a bottleneck i guess but with the way the game behaves now i can't be sure. For example, people say the game doesn't use more than 2GB for now and since my win7 reserves between 0.9-1.1GB i should be doing fine, even if barely so.
In any case i'm not upgrading anything until some more optimizations are complete.
The problem is not performance per se, it's the fact that the performance is highly unstable and hard to predict. I've flown a couple more sorties now and got worse performance than the previous two, even though i was running less and smaller aircraft
I'm waiting till these hiccups are patched away before i can really say if there's something wrong with my system.
As for the graphics card, the 4890 is one of the last DX10 models to be produced. In fact, it's a bit faster than some of the first DX11 cards to hit the market (like the 56xx-57xx series for example) and since the game is running DX10 for now i see no reason to upgrade that.
I'll be doing some tweaking tomorrow, installing the new Ati drivers, etc, to see if i can improve things further.