Heat Problem.

[Nocontact]

My buddy has a rig with a P4 3.0 ht, 1gb of Ram, and asus P4P800 S Mobo, with a cd-rw and dvd-rw, as well as an 80GB IDE drive and a 300GB SATA drive.
He is running a 350W power supply.

Sometimes his case gets hot, you can actually feel the warmth on the outside of it and of course he's concerned. It doesn't seem as though performance is an issue but I'm wondering if he needs a more powerful PSU or maybe another fan inside the case to help things out a little.

I installed mobo monitor to check what the temps are like and I wasn't too pleased.
By just downloading 2 torrents the cpu temp climbed all the way to 59degrees but what was also strange was that task manager said the cpu use was up to almost 60% and this was with no other processes running.
It seems to be a problem with the cpu fan/heatsink combo. Am I right to assume this?

[Whyzman]

Welcome tohttp://www.pcguide.com/ubb/pcgubb.gif Forums!

Here's an excellent read on Power Supplies:

http://www.firingsquad.com/guides/power_supply/

Today's computers draw heavily on the 12v rail which in the past was not really an issue. However, with today's fans and CPUs it definitely is an issue.

I would suggest removing the cowling or side of the case and let a fan gently blow on the computer's innards. See if that makes a difference in the temps...

How many fans are you currently running and where are they placed?

[Nocontact]

Thanks.
Is there a reason why my instant email notification doesn't seem to be working?

There is the case fan at the front, and the cpu fan as well as the psu fans. I think I definitely need to add another fan at the back because there's a slot there too.

[r53s]

The back fan is more important than the front one...

[Paleo Pete]

I would try moving the front fan to the back, so the power supply and case fans are both pulling air out the back of the case, try the fan blowing into the case as suggested above, and check into thermal compound for the heatsink. If you're having heat problems that's not a good thing, and you might look into using Arctic Silver thermal compound, and sometimes lapping the heatsink is useful. Lapping gives it a smooth and flat surface, fewer places for air gaps and usually will help lower temps a bit, but don't expect it to make a drastic difference...Seems like mine dropped 5°F after lapping it with up to 600 grit sandpaper. That's not a major decrease in heat but enough to make a bit of difference, especially if it's running warm to begin with.

The reason lapping helps is most heatsinks are made from extruded aluminum, and few are then machined flat. The bottom mating surface is almost always convex or cupped slightly, due to contraction as it cools faster on the outside than in the middle. That means the heatsink only touches the CPU on the 4 corners, leaving a good sized air space in the middle. Lapping flattens the mating surface so it has better contact over the surface of the CPU. If you try it, lapping should be done carefully and with a light touch, it's very easy to take more metal off the corners than the middle and and up with the same problem you started with...insufficient surface contact. A flat surface should be used such as a pane of glass, a polished granite lapping block is perfect, but expensive. You can find out how flat your heatsink is by LIGHTLY working it on a sheet of fine grit sandpaper for a few seconds. 600 grit should work for this. If the corners are shiny and the middle dull, it's cupped. It only takes 10-15 seconds, you only want to lightly polish the corners to see whether it is flat or not. If you want to spend some time cleaning it up, paint the surface with a non-permanent magic marker, the sanding marks will be very visible. Clean it off with alcohol or fingernail polish remover.

Clean the dust out of the case (if any) and re-position or add fans, check thermal compound and if that doesn't bring temps down to a satisfactory level then check into lapping it. The location of the computer can make a difference too, if it normally sits inside a small cubbyhole in a desk make sure the door stays open. If it's out in the open try sitting it on a milk crate or similar box to see if getting it off the floor will help. Also keep it away from the wall, so it can get better air circulation.

[Matt]

Something else that can cause your CPU to reach higher than normal temperatures is dust buildup. When my CPU temperature starts to climb when it shouldn’t, more times than not dust has built up between the fins on the heat sink restricting airflow. This is something that you can just visually check while the computer is off (and just to be safe unplugged).

Be careful with fan placement as well. When you install fans in the back of your computer, you’ll probably want to position them so that air is directed OUT the back of your PC (as Paleo Pete said), but if you don’t have any/enough fans pulling air into your case; any gap, crack, crevice that air can flow though including the vents that will probably be on the front of your computer will all be entry points for dust (since you’re forcing more air out than in).

An example is a computer I had built inside a colorcase tower. I installed an 80mm case fan to exhaust air out the back of the computer. However, where I lived at the time was really dusty, and dust would find its way into the case from around the drive slots, side panels and through small vent wholes drilled in the side panels. A handful of these vent holes were directly across from the CPU on either side. It would take about a week or two for the CPU heat sink to become overwhelmed with dust buildup and would require cleaning; otherwise the computer would become too hot and ultimately unstable. This wasn’t a problem before installing the 80mm case fan. I’ve since purchased an Antec case with a built in air filter in the front of the case. The amount of dust and whatever else is floating around in the air is much less where I live now. However, the amount of dust/lint/whatever that I clean out of this filter monthly is still amazing (2-3 months and it is completely clogged).

As long as you’re sure that your power supply can handle it, I’d recommend putting a fan in the front of your case as an intake fan with a filter between the fan and outside air. Or, at least put case filters up in the open case vents.