god, so many uninformed people in here...
The so called "micro-stuttering" is a phenomenon that appears with ANY MULTI-GPU setup.
Basically the frametimes are not constant, they are irregular which means GPU 1 will render the first frame faster while GPU 2 will render the second frame slower, ultimately causing a small 'delay' between frames.
Heres an example in Stalker with a single HD 5850 compared to two 5850's in CF
As you can see, the single HD 5850 refreshes each frame within 36 milliseconds which is a constant frametime allowing for smooth gameplay.
However, once you put a second card in the micro-stuttering will appear.
One frame is always being refreshed after ~13 ms while the second one however takes around 50 ms simply due to the GPU's having to communicate with each other. So opposed to a constant frametime you will see an almost ~40 ms delay each second frame and THAT is basically the micro-stuttering.. has nothing to do with driver issues, gpu utilization or other funny stuff that has been mentioned here.
And yes, Vsync does improve it because it uses frame buffers which means frames are already pre-rendered and can be output in a constant way. (note it doesnt necessarily fix it, but definately dampens the stuttering thanks to more constant output of frames)
Micro-stuttering is TOTALLY subjective; some people may notice it, others may not.
It may also be worth noting that nVidia has this issue WAY better under control than AMD. The frametimes on a SLI setup are much more constant than a CF setup, see here: http://www.computerbase.de/artikel/grafikkarten/2011/test-radeon-hd-6900-cf-vs.-geforce-gtx-500-sli/20/
Also, it might be worth checking out the attached links below so we can save 9 pages of non-sense next time.
So next time do some research about the product and its related issues that you're buying OP....
Either sell your card and go single-GPU or use Vsync, no driver or OS reinstall will fix this issue.Edited by toX0rz - 12/11/11 at 2:21pm