how "bad" the stuttering is is dependent to preference. some people dont mind it, others think its bad. for instance ill use an example, the intel stock cooler. some people dont mind the noise it makes and it doesn't make much noise, others dont like it and prefer to replace it with even a cheap cpu cooler just to rid of the fan noise.
I have a very similar system, the only difference is I have HD 6870's in CF and I have 16GB of RAM (not relevant). I hardly notice micro suttering at all and it performs very well. The only issue I've ran into just recently is being limited by 1GB VRAM, but the only game that I play that eats up Vram is BF3 and I can still run on very high/ultra custom settings.
Resolution is the first, graphical density(quality) is the other. the third one that is less mentioned is field of range, field of range in which your gpu is calculating the actions on the current map largley play a factor in vram usage. Most games will not use over 1 gb of vram except when you get into games that are either heavy on quality or have a long field of vision(prominent examples would be skyrim and battlefield 3) which can go past 1gb and usually hit around 1.2-1.5gb vram at times.
This will last me about a year and then im going to get a VERY nice grpahics card(saving up for a 600-700one depending on what is out) but until then I just like you said want a gpu that can play games like butter...
also if i turn down one setting in the settings will that reduce the v-ram usage.