Best drivers for Nvidia Card

The official WHQL Nvidia Drivers are often the most stable and effective, however they often don't offer the best performance.
The Nvidia Betas often offer very good performance , even if sometimes the image quality is not as good as the WHQL variants.
I however, would suggust, for optimal performance and image quality the drivers offered by Tweaksrus.
The drivers are titled XG drivers and come in all the normal variants. Windows Vista, Windows x86, Windows x64 etc. The site to obtain these drivers is www.tweaksrus.com , and they offer the most downloaded drivers for download on that site as well as a very helpful forum.
I have found through extensive benchmarking that the xG 91.21 drivers provide optimum performance for both my 6600gt and my 7800gt.
Games are smooth and FPS is , on average , 4 fps higher in most games (over the latest WHQL nvidia drivers). Which may not seem like much but just for driver changes its a significant performance increase. The image quality of this driver is also second to none and the smoothness is outstanding.
I would suggest all Nvidia users to use xg drivers offered at www.tweaksrus.com