Cheap Laptop Cooling!

by CalcProgrammer1

43K3438

Intro: Cheap Laptop Cooling!

Well, I got a new HP dv9700t for college, but when I play games on it or run any intensive task, it heats up to really high temperatures. I don't want it to break, so I'm trying to cool it. I bought a $40 Rosewill laptop cooling pad, but my GPU still stays around 90C under stress. The Rosewill pad has a nice metal slab to take the heat off, but only two puny USB powered fans that don't put out a whole lot of air.

However, I had a dead dual-fan desktop power supply laying around as well as a fan I tore out of a different power supply (replaced it with a blue fan).

I also had another old PSU lying around that I replaced when I upgraded my graphics card. So, with all of these, I built a very effective laptop cooling fan.

STEP 1: Do You Need to Cool?

First, you need to make sure you need a cooling device. If your laptop is only ever used for web browsing and document editing, chances are, cooling units won't help. If you play games a lot, then you'll probably want a cooling device, as gaming stresses the CPU and GPU and causes immense heat output which often can't be handled by the single small fan most laptops have.

Use PC Wizard (www.cpuid.com) to inspect the temperature of your CPU, motherboard, and GPU as you play games (I hooked up a second monitor, put PC Wizard on it, then fired up games and watched the temperatures change). You can minimize PC Wizard and it will have a small status/temperature notification at the top right of your screen.

STEP 2: Take Apart the PSU!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!BE CAREFUL!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Computer power supplies (PSU's) have capacitors that can carry a powerful shock, enough to kill you. They hold this charge for a fairly long period of time. If you take apart a PSU, you're safe as long as you don't touch the underside of the circuit board OR any of the capacitors OR any of the metal contacts on the parts...in general, just don't touch the metal stuff on the circuit board. I touched the heatsinks, but those are usually just grounded so no big deal. Wear plastic gloves if you so desire. This PSU was a $13 model purchased from Newegg to power a cheap rebuilt PC. It lasted 3 months before I accidentally bumped into the PC and the flimsy heatsinks touched and shorted and fried the PSU (not the computer, thankfully) and took out my whole room in the process (stupid GFI). Newegg RMA'd it and sent me a new one, but due to the cheapness of the PSU, didn't ask for the old one to be returned. Instead of just throwing it out, I figured I'd salvage stuff from it. The first thing to take are the fans.

Take apart the PSU by removing the cover screws. Then you can take the fan off by unscrewing the four fan screws (usually from inside the PSU case). Repeat for the rear fan if your PSU has one.

If you don't have a dead PSU, you can buy cheap case fans online, buy expensive case fans in stores, or ask people who have lots of computers (they might not give them to you though...). You can also find a dead PSU from said people.

STEP 3: Tape the Fans Together

Simple, lay all 3 fans flat (make sure they're all facing the same direction, the side with the plastic tabs and motor cover (usually a label sticker) is the side air comes out of). Make sure the wires are coming out of the bottom of all 3 fans. Then take electrical tape (or your favorite kind of tape, whatever you want) and tape around all 3 fans until they form one big solid fan brick.

STEP 4: Solder the Connections

Solder all the black wires together and all the red wires together. Use electrical tape to cover them and keep them from touching. You only need one connector (I used a 4-pin Molex, which is a good choice if you have an old PSU to run the fans with).

STEP 5: Power It Up!

If you're using a PSU, you have to jump the green wire to a black wire on the ATX connector. Then plug in your fans, set it next to your laptop, and watch the temps fall.

36 Comments

Just4Fun Media 8 years ago

Great instructable! I built a similar system that is self powered off of the computers waste heat! And I was able to reach core tempatures of 4.2 degrees Celsius!

https://www.instructables.com/id/Self-Powered-Computer-Super-Cooler/

alaskansnowboarder 10 years ago

Buy a harddrive power supply the dual voltage 12v and 5v @ 2amps .. I purchased these in bulk and have many uses, because they have the dual voltage. I use them in my greenhouse to power 120mm PC fans. I use pvc pipe to make a mount for my fans..

OzzyManson 10 years ago

what MM of fan would you suggest for this? my laptop is currently sitting at 51*C and im not even playing games or really doing anything.

vanwazltoff 11 years ago

if your computer is running at ridiculous temps you probably need to replace the thermal compound with something like timtronics grey ice 4200. thermal paste should be replaced at least every 2 years, this explains why it gets hotter and hotter over time. a good quality thermal paste can significantly decrease processor/graphics temperatures. companies such as HP do things on the cheap and dont use a quality thermal paste and often run way too hot out of the factory

CalcProgrammer1 11 years ago

The laptop died a year later of heat-related GPU failure, once it came back with a new board I eventually tore it apart and re-applied paste (Arctic Silver 5, not the best but it's what I had) which did lower temps. Recently got a new laptop that doesn't run so hot, it's an HP but it's AMD based.

MRedu 12 years ago

Great guide +1 especially if you have a cheap laptop that is overheating. One thing i was wondering, does it matter if the fans are blowing air away from the laptop or into the laptop? Or does it matter?

tomkat1982 13 years ago

Very helpful. Great stuff, thanks.

rkr 14 years ago

90 degrees should technically be burning up. And if anyone's interested (as I was reading some other comments), here is a great site for pin-outs: pinouts.ru/Power/atx_v2_pinout.shtml

kenshinruff 14 years ago

When I jump the green wire to the black wire there is a noticeable ring emanating from the psu that is not there when I have it connected to a motherboard. Anybody know how to fix this?

CalcProgrammer1 14 years ago

This could be from a weak capacitor or a worn out fan. Switching PSU's (what ATX PSU's are) use high-frequency AC electricity which can sometimes create a high-frequency audible sound, usually from the transformer. I guess it has to do with how much power you're drawing. If you're only running fans, chances are the 5V (red wires) rail is not connected to anything.

shadowsniper918 15 years ago

the green wire is that the "sense wire" to trigger psu to turn on ?

CalcProgrammer1 14 years ago

Yeah, ATX power supplies have an always-on +5V Standby (the purple wire) that is always on. To turn the rest of the power supply on, you have to short the green (PS-ON) wire to ground. It's basically the power switch for the PSU.

mikemmcmeans 15 years ago

when i'm running world of warcraft and windows media player the temp tops out at about 60C on each core

UberPug 15 years ago

whoa.. 90 degrees is serious. is that even safe?

CalcProgrammer1 15 years ago

Probably not, that's why I really needed to cool it off. The computer only has an 8600M GS but must have a very poor heatsink. Laptop stuff is designed for higher heat tolerance than desktop though, because laptops obviously have poor cooling (usually one 40mm fan or so for a dual core CPU and a graphics card) while desktops have better cooling.

Derin 15 years ago

my desktop runs at 60deg with a clogged fan

CalcProgrammer1 15 years ago

Desktop parts always run much cooler than their laptop counterparts. An average desktop CPU should run around 40-50 degrees, maybe peaking near 55 to 60 under intense loads, while laptop CPU's idle around 50-60 on normal cooling (the built in heatsink/fan) and approach 70 under intense loads. This is because the CPU on a desktop has a big block of metal sitting right on top of it as well as a large fan on top of that. Desktops also have case fans, room for air to move around, separate GPU fans, and sometimes intake fans. Laptops usually share one heatsink for the GPU and CPU, usually with just one tiny 40mm or so fan that gets limited airflow due to the small opening and lack of empty space in the case. With real desktop fans cooling a laptop, you can get much lower temps (my CPU idles around 30 with the 3 desktop fans blowing on my laptop).

smurfsahoy 15 years ago

Wait what? How would a mere fan get anything below room temperature? Once your CPU drops below 70 or whatever it is in the room, even infinitely increased airflow should warm the CPU up, not cool it off.

smurfsahoy 15 years ago

Oh celsius, nevermind hah