As far as Nvidia/Ati seriously lets get a life...
Remember the law suites going on because they were working together and fixing prices and competition... You think its really ended?
As far as core technology is concerned ATI is massively ahead of Nvidia, speed wise they are yet neck and neck with the top cards.
As for the drivers... They will shoot off whatever number they can get in one system in one program in one situation to make them sound good, did anyone really think you were going to see a 30% performance gain with a driver? Possible sure, probable not really.. As for the speeds lets get real .5-2% performance can vary that much at random, so the tests are basically completely inconclusive.
As for stability and jitters, I am VERY pleased, I was having issues in Guild Wars with my 4850 until these last drivers, was running a nice good 200fps, and then turn and boom drop to 70, that doesn't look too pretty when it happens.
Stability first, then tweak, then more stability and then more tweaking, you don't put together a new computer and just bang your overclock to 500fsb do ya? No you step it slowly until you get the best you can and staying stable, run into a wall, you slowly find your way around it and find out how to make it stable at the same time.
Give it some time, few months yet these drivers will be rock hard and give some actual performance boosts.
