My mini itx build, with a cooler master elite 120 case and an intel i5 3570K with stock cooler averages around 35-40 degrees across its cores when idling. Right now I'm running a blend test for about 30 min, downloading a game on steam and typing this, and my cores are averaging about 85-90 degrees. Is this too high? I want to leave the PC on permanently and I want it to have a good lifespan and perform on gaming, what are some things I can do to cool it down?
I have added an additional 120mm fan to the case interior facing the cpu and memory, and I have removed the front panel allowing full access to the 120mm intake fan, but while adding fan filters to it and the 80mm intake fan on the side of the case. My PSU intake fan is facing up and out of the case. I have no fans actively blowing air out, and that one interior fan moving air from the front intake to the cpu. Would this be positive or negative pressure and which should I have?
Your idle temps are pretty good. I'd try testing under a normal kind of load, heavy gaming etc, and see what kind of results you get. 85-90 is definitely too high, but unless you've tried overclocking on the stock cooler it's unlikely you'll hit that under normal circumstances.
You can also improve your airflow. It's not going to make a world of difference, but it'll certainly help. More than anything else you want an exhaust near(ish) to your CPU. As a general rule you use front/side fans as intakes and back/top as exhausts.
Your PSU is in correctly, you have an intake vent on the top and it'll push hot air out of the back.
This image would suggest none of your fans are used for exhaust, and there doesn't appear to be a location to mount one http://www.coolermaster.co.uk/upload/product/6837/galle...
I do not overclock, so the load temps are from just regular use. I was thinking I could just mount the fan to a vent, nothing too big, maybe even one of those laptop fans with the low profile and self encasement.