I've just ordered a X2 4000+ Because I can't get my X2 3800+ @ 2.7GHz Stable.
I thought a better cooler would help, I received my Zalman CNPS9500 and 2,66GHz stable is all I still get. About the same as with the AMD stock cooler.
But the temps are much better compared with the stock cooler. 45 degree C. under load, and 38 idle. That's pretty nice compared with up to 70 degree with AMD's stock cooler.