im using a hyper 212 on my i5 2500k at stock, im getting temps in prime 95(after 2 hours) between 49-51,
not sure 100% sure on my ambient temps but cpuid is showing my hd assembly temp is 26,i think ambient is closer to 22-23,
gonna get some extra case fans and probbaly an akasa venom 120mm fan to stick on the hyper 212 for push/pull set up and then see how far i can OC.
Tbh i'm really impressed with the i5 even at stock, i went from pentium 4 to this
My case is haf 912 plus
If you just built the pc today the thermal paste might take time to cure, so temps might improve a bit over time,
My core #0 is always coldest and core #3 the hottest