computer heating problem

My computer has been getting pretty hot lately so ordered a few fans for it. I was wondering if i stick a pci slot fan under neath my video card would it create a vacum and f-over my video card? Also I have been told your supposed to have a fan sucking air into the computer, anyone know if thats true?
Thanks for your help

Try running it in the bathtub

j/k

Yeah...you need intake and out umm.. outtake? sorry brain fart. Anyway, the fans on the front of your case should be pulling cool air in and the ones on the rear should be pushing the hot air back out. A PCI fan will not create a vacuum, but rather circulate the air (and the heat) from your GPU.

Generally, you should have a fan at the front to pull air INTO the case, and other fans to push it out.

Example diagram which I quickly googled:

http://www.overclockers.com/tips461/thrucase.jpg

Well see the problem is I have no where for fans to go in the front of my case. I built my computer myself and didnt even think about the design of the case. I just thought it looked neat so i bought it, stupidity on my part. Does the fan on a video card suck air to it or away? Thats why i was concerned about the vacum, having 2 fans in one little spot fighting over air to take.

I think the GPU fans I've seen pull the air ovee the heatsink by blowing the air away from the card. It is possible that multiple fans inside the case to form little circles of hot air, although if you have enough intake holes in your case you can usually get enough cool air to mix into the vortices.

Alternatively, you can ensure that you are getting cool air into your case at the right place by sealing all of the holes in the back and making sure you have holes in the front and sides, preferably either (1) opposite from the outgoing fan, with the hot pieces in between or (2) near the hot parts (CPU and GPU).

Years ago I successfully did this for a 350 MHz AMD, attached a bigger heatsink to the CPU, and was able to run the thing without a CPU fan. Of course, I poked a jagged hole in the front.

Another trick is to pull the heatsinks from you GPU (and CPU) and reapply some quality thermal paste. I'm currently running an AMD 650 without a CPU fan at home and got the CPU to run15 degrees cooler just by using better thermal grease (the poisonous silver stuff). Good paste has also allowed me to run a GeForce3 without the fan it came with.

Finally, you could just yank the cover and run the computer exposed. That and a really nice copper heatsink allows me to run a Celeron 1.2 GHz without a fan (which is all stuffed into an aluminum Zero Halberton briefcase, and which I am currently typing on).

Most of my experience has been in trying to get rid of the fans (for less noise) rather than adding more.

Andrew I think ill try some of that, my computer sounds like an air plane. if all else fails ill just by me a new case that will give alot better air flow.
thanks for your help everyone

Fuel, you don't mention what you're trying to run, at what speeds, and in what type case, which might help suggestions and diagnoses.

However, a few things sprung to mind as suggestions:

If the GPU fan is standard orientation (on the PCI side of the card) having a correctly oriented fan _in_theory_ should not harm the performance of the gfx cooling. However you may get noise weirdness due to the GPU fan getting slightly overspun (perhaps) by the PCI fan. However, if you sort out your overall case temps then the standard cooling solution for most GPU's should cope with the load without alteration, providing you're not overclocking the card.

As Andrew says, thermal paste, decently applied, is a must. Remember as little paste as possible! A _thin_ layer across the contact patch is enough providing the heatsink's sorted properly. Too much goop actually impairs heat transfer.

As far as CPU sink is concerned, try and find the largest one you can generally, as these often come with larger/slower fans. The cooling potential is usually as good as or better than an OEM heatsink/fan combo, and will often have the benefit of running quieter. 60mm fans running over 5000rpm are a pain...

Casefan wisdom I've seen follows the premise of "heat rises upwards", so you want big and slow input fans in the lower portions of the case where all the cold air is. Again, a bigger fan running slowly is often better in terms of air transfer and noise than a small one frantically spinning.
I've always regarded case extractor fans as optional - you already have one fan pulling air out of the system in the PSU normally, and to assist this and prevent dust problems you ideally want "positive pressure" in the case.
What this means is you have more air actively being pulled into the case than you have being actively pulled out. This ensures that dust doesn't get drawn into your system through convenient apertures like the CD-ROM drive, for example. A problem you don't really want to have...

Try these things step by step, I suggest. Start with the thermal compound, and see if that helps. Then I'd say go for a larger CPU fan, then a large single casefan drawing air in wherever you can fit it. You may find with a decent CPU cooler you can stop the process there.

Good luck, and try not to do what a mate of mine did and progress to spending hundreds of dollars on watercooling.

Happy trails.