warrencr, it depends.
If you can afford it
, then I would go with a 920 + 2x Gentle Typhoon 1850rpms in push pull.
But even the 620 is more than enough to adequately cool the 2500K, these are very cool running chips even oc'ed
But if you can afford it, then go with the 920+2x GT 1850
If 920 is a bit too expensive for you, then 620+2x GT 1850's is also a good choice if your motherboard can adjust the speed of 3pin fans, atleast my Gene-Z supports.
I have 620 because that was all I could afford at the time being.
I have it with 2x GT 1850rpms, and it can easily cool my 2500K.
Load temperatures with 4500Mhz using 1.3vcore
I am getting around 55-65*C load with ambient temperatures around 17*C
And with my testing using IntelBurnTest 2048mb load (strictly for temperatures, not stability)
I am getting around 40-44 delta when my fans spin full speed (~1700rpm and ~1800rpm)
That means the temperature of the processor ABOVE ambient temperature.
Explained further: if you get 60*C load temperature for processor, and ambient is 20*C, that means your delta is 40*C
Explained because wasn't sure about how experienced you are, apologies if you already know this kind of stuff Edited by lagittaja - 8/17/11 at 3:47pm