Just got a H50, my old HSF was a Tuniq Tower with a replaced PWM fan from GELID, which cooled my OCd AMD Ph 9850 3.1GHz 34idle and up to 58C full load from prime,OCCT,folding.
With my nice and fancy H50 thats set up like so...
Scythe 3K < 25mm Shroud < case wall < 25MM Shroud < H50 Rad < Inside of case
the Scythe and one 25mm fan shroud are outside of the case, then the H50 rad and another 25mm shroud are inside of the case. at first with movement of fans (two 3ks used to be the exhaust on the top of the case) my internal temp skyrocketed up to 37C!!!! but it has been very hot. now ive gotten the internal temps under control, and as i type this, i am running one SMP client and one GPU client, so gpu and cpu full load, and my processor temp is 46C!!!!
Thats right, a 12C drop!!! (and internal temps are 32C)
the scythe isnt even on full power, i have it on a fan controller, and its going at about 1k RPMs or less. i havent seen any difference in temps with an increase in speed beyond that point
ill upload a actual photo of the setup when i get a chance