4790K temp spikes

[Jokkis]

I have a 4790K in a water loop with R9 290X DCII crossfire. Idle temp is 25-30 degrees. When I run Prime95 temps start out at about 55 degrees C. After 5-7 mins the temp spikes to 75-80 and stays like that for a couple minutes before it returns to 55-60. This goes on in 7 minute intervals. CPU is clocked to 4,4GHZ at stock voltage (1,3V). This also happened at stock 4,0GHz also so I changed thermal paste from EK to some other quality stuff, but no change. I have 2 120x360 radiators.They are able to keep both 290X's at 60 degrees (1130MHz core clock and 5800MHz memory clock) during full load. CPU block is EK Supremacy EVO AC+NI. After 40 mins of testing my max temp is 82, but temps are 60-65 atm. Temps are about the same on all cores. I have had a 2600K @ 4,8GHz and 1,42V since 2011, never had unstable temps like this. Am I just very unlucky with this chip or is there a solution here?

 

[andreaszero]

It's a common problem that the Devil's Canyon 4790k is getting hot easy. Some times, including my friends scenario, the right thermal paste makes the difference. My friend change from Noctua N1H1 to Arctic MX-4 and, believe it or not, saw a difference of 11 degrees! Go buy some, it's not that expensive, and see if it helps. Other than that, as I said above, the 4790k gets very hot.