I recently build a gaming pc and when i play a game it shows in real time that my cpu tempt is about 70 degree and 45 degree when doing normal browsing. Im using a stock heatsink. Is it safe or should i consider a aftermarket heatsink? Any recommandation?
Stock cooler blows. Get some proper cooler. I got I7-4770 non K and it runs 30c idle and 57ish load. That is with the averagish Arctic Freezer I30 cooler.
Of course you also should make sure your case is well ventilated. I put a little money towards N500 case from Cooler Master and slapped on 2 extra side fans in it and they do magic there, my Radeon 6990 lost a good 6-7c at load just from that and I'll stick another 3 fans in that case (simple 120mm fans cost a couple of bucks).
So what I am saying is get a better cooler and grab a couple of simple 120mm fans to boost your case vent and you will slash 10-15c there easy.
I use the coolermaster trooper black case. There are 2 fan in front, one big fan on top and one on the back. I dont get why its over 70. And im not overcloaking them. The case is quite spacey. Should i buy external fan to help reduce the heat?
Fluid dynamics. If you have a big case, it's going to take more airflow to refresh all that air. Also check your cable organization, as cleaning up your case will improve your airflow twice as much as it will improve it's aesthetics. Given that the i7 is an expensive investment, you should do your best to protect it by buying an aftermarket cooler, as temperatures in that range will definitely shorten the lifespan of your CPU.
Actually on second thought (just read your case layout) it might be that your thermal paste has dried up/crystallized. Even though the stock coolers are crap, if you don't wanna invest in an aftermarket cooler, a new fresh application of Artic Silver thermal paste will certainly improve your heat issue by a few degrees C.