My ram is currently naked, becuase I changed the stock cooler for a waterblock..
I would guess they are hitting 60-80°c for the naked chip in games.
Ive looked at the samsung datasheet and the rated power disipation is left as "TBD" which is helpfull.. and theres no c/w value for the package.. - things usually included in datasheets... but they put in max junction temperature of 125°c..
Site:
http://www.samsung.com/Products/Semi...ily_cd=GME1001
Datasheet:
http://www.samsung.com/Products/Semi...23qf_rev18.pdf
Mine has the 1.6ns ram, K4J55323QF-GC16.
I will probably make up some mensinks anyway. The X850XTPE has mounting holes which cant be wasted..