Computer Cooling
Aug 8, 2006 22:38:15 GMT -5
Post by Lamron on Aug 8, 2006 22:38:15 GMT -5
A couple of weeks ago, the server CPU fan died and the computer was up at 185oF when I found it. It had shut itself down and appears to have suffered no damage. A $6 fan screwed right in and fixed it, so it wasn't any big deal.
It did get me thinking about cooling though, so I decided to see how cool I could get it without any extreme or expensive mods. I thought I'd share what I did to see if it would help anyone else.
First, a few things before you start looking at cooling your computer:
- Location. Make sure its not near any source of heat and that there is plenty of airflow around the computer. If its shoved up against the back of a cabinet an inch from the back wall, its going to get hot.
- Before you do anything else, open up the case and CLEAN IT. It worked fine when it left the factory, maybe its just too dirty now to work effectively. You may need to remove fans to get to the heat sink fins. These must be very clean!
- Turn it off. If you're working on a running computer, you may get electrocuted, or worse, you might drop a screw down in it and short something out. (I ignored this rule and risked my life working on a running computer so that I wouldn't have to shut down the server and interrupt your play.
- You need some way to measure your temperature. I can't give any recommendations, because different computers require different software for this. Google "cpu temperature monitor". You may have to try several before you find something compatible with your motherboard. Some of them give lots of other info, but really all you need is Case Temp and CPU Temp.
- Use at your own risk! If you set your computer/desk/house on fire trying anything I describe here, I don't want to hear any complaints! (take lots of pictures though, so we can make sympathetic comments about your burning computer, while secretly ROFLMAO).
======================================================
Common upright computer towers suck air through the front and blow it out the back. You should see two fans on the back, one for the case (lower) and one for the power supply (upper). Make sure your power supply fan is blowing OUT. Reportedly, some are designed to suck air in through the back and exhaust it inside the case. This is a stupid design. If yours does this, disassemble the power supply and reverse the fan so it blows out the back of the case.
On some computers, the fan grill is just a bunch of holes punched in the metal. This causes too much resistance. You can cut out the whole circle to improve airflow (I'm assuming you're smart enough not to stick your fingers into the now-exposed fan blades). Use tin-snips or heavy-duty wire cutters to cut each of the connecting holes at the thinnest part. It doesn't make a nice neat cut, but it does prevent metal shavings from most cutting tools from getting inside the case.
(ignore the stylish cardboard case for now)
Next lets look at the fan. This computer had a 60mm fan attached to the CPU heat sink.
I decided to upgrade to a 80mm fan, so I got an adapter/spacer to allow the bigger fan to mount.
The new fan has three immediate advantages:
1) Almost twice the CFM.
2) Half the dB rating.
3) Spacing the fan out from the heat sink eliminates the dead spot in air flow caused by the fan hub. Now all the heat sink gets air.
So now I've got this big fan pushing air though the heat sink. But where's this air coming from? Inside the case, where its already pre-heated by other components. For maximum cooling I decided that the fan needed to breath cool, outside air. So I mocked up a tunnel to the outside of the case and put a second, identical fan there. Usually, you don't want to stack fans because the turbulence between them actually reduces their output, but my tunnel spaces them apart several inches so it does improve air volume.
So far, the only point of exit for hot air is the fan at the back of the case, but its half way down (below the power supply). Since heat rises, the case could benefit from a top vent.
This is where the stylish cardboard comes in. If you have a metal case like this one, you can take off the sides/top and replace them with cut-to-fit cardboard so you can test different configurations before doing any permanent case cutting. I tried many different locations and numbers of fans and found that some layouts actually make it hotter by causing turbulence inside the case that can't excape.
So, I mounted an exhaust fan in my cardboard top, and moved the CD-ROM to a lower bay for more open space at the top of the case.
Next, I added an input fan to balance the two exhaust fans I now had running. At the front of the case there was an empty space where air was supposed to be inhaled (I had to relocate a tiny PC "beep" speaker).
Ignore the terrible hack job on the metal. I was trying to cut a roundish hole with tin-snips instead of doing it right with a hole saw because I was afraid of getting metal shavings all over the motherboard. The front of the computer completely hides it anyway.
So now my airflow is,
IN: front case fan, cpu fan through heat sink
OUT: back fan, top fan
During testing, I found that leaving the case open was worse than stock cooling. Without a specific path to follow, the fans don't do any good and the air stagnates. So, on with the cardboard side cut out to receive the CPU fan tunnel.
When I'm satisfied that I've got the best layout, I'll cut the original metal sides to fit the new fans.
With this set up I get these temps (with the server running):
CASE: 82o
CPU: 105o
This is ~9-10 degrees cooler than the stock setup on its best day. The heat sink feels cool now, so I think I've reached the limit of what can be done with improved airflow alone. To go cooler, I'd have to replace the heat sink with a better one made from copper. These temps are quite good for a computer under load, so there's no real reason to go any farther, other than because I can!
The four-pack of 80mm fans was $15 and the 60/80mm adapter was $4, so obviously I haven't spent much money. If you want to make your fans more finger-friendly, you can buy grills with the fans.
In my estimation, the most beneficial additions where the front and top fans, and removing the grill restrictions on the back fan.
All extra fans should be plugged into the power supply, NOT the motherboard. The mother board probably supplies your original fans, but the additional current of extra fans may be too much for it.
It did get me thinking about cooling though, so I decided to see how cool I could get it without any extreme or expensive mods. I thought I'd share what I did to see if it would help anyone else.
First, a few things before you start looking at cooling your computer:
- Location. Make sure its not near any source of heat and that there is plenty of airflow around the computer. If its shoved up against the back of a cabinet an inch from the back wall, its going to get hot.
- Before you do anything else, open up the case and CLEAN IT. It worked fine when it left the factory, maybe its just too dirty now to work effectively. You may need to remove fans to get to the heat sink fins. These must be very clean!
- Turn it off. If you're working on a running computer, you may get electrocuted, or worse, you might drop a screw down in it and short something out. (I ignored this rule and risked my life working on a running computer so that I wouldn't have to shut down the server and interrupt your play.
- You need some way to measure your temperature. I can't give any recommendations, because different computers require different software for this. Google "cpu temperature monitor". You may have to try several before you find something compatible with your motherboard. Some of them give lots of other info, but really all you need is Case Temp and CPU Temp.
- Use at your own risk! If you set your computer/desk/house on fire trying anything I describe here, I don't want to hear any complaints! (take lots of pictures though, so we can make sympathetic comments about your burning computer, while secretly ROFLMAO).
======================================================
Common upright computer towers suck air through the front and blow it out the back. You should see two fans on the back, one for the case (lower) and one for the power supply (upper). Make sure your power supply fan is blowing OUT. Reportedly, some are designed to suck air in through the back and exhaust it inside the case. This is a stupid design. If yours does this, disassemble the power supply and reverse the fan so it blows out the back of the case.
On some computers, the fan grill is just a bunch of holes punched in the metal. This causes too much resistance. You can cut out the whole circle to improve airflow (I'm assuming you're smart enough not to stick your fingers into the now-exposed fan blades). Use tin-snips or heavy-duty wire cutters to cut each of the connecting holes at the thinnest part. It doesn't make a nice neat cut, but it does prevent metal shavings from most cutting tools from getting inside the case.
(ignore the stylish cardboard case for now)
Next lets look at the fan. This computer had a 60mm fan attached to the CPU heat sink.
I decided to upgrade to a 80mm fan, so I got an adapter/spacer to allow the bigger fan to mount.
The new fan has three immediate advantages:
1) Almost twice the CFM.
2) Half the dB rating.
3) Spacing the fan out from the heat sink eliminates the dead spot in air flow caused by the fan hub. Now all the heat sink gets air.
So now I've got this big fan pushing air though the heat sink. But where's this air coming from? Inside the case, where its already pre-heated by other components. For maximum cooling I decided that the fan needed to breath cool, outside air. So I mocked up a tunnel to the outside of the case and put a second, identical fan there. Usually, you don't want to stack fans because the turbulence between them actually reduces their output, but my tunnel spaces them apart several inches so it does improve air volume.
So far, the only point of exit for hot air is the fan at the back of the case, but its half way down (below the power supply). Since heat rises, the case could benefit from a top vent.
This is where the stylish cardboard comes in. If you have a metal case like this one, you can take off the sides/top and replace them with cut-to-fit cardboard so you can test different configurations before doing any permanent case cutting. I tried many different locations and numbers of fans and found that some layouts actually make it hotter by causing turbulence inside the case that can't excape.
So, I mounted an exhaust fan in my cardboard top, and moved the CD-ROM to a lower bay for more open space at the top of the case.
Next, I added an input fan to balance the two exhaust fans I now had running. At the front of the case there was an empty space where air was supposed to be inhaled (I had to relocate a tiny PC "beep" speaker).
Ignore the terrible hack job on the metal. I was trying to cut a roundish hole with tin-snips instead of doing it right with a hole saw because I was afraid of getting metal shavings all over the motherboard. The front of the computer completely hides it anyway.
So now my airflow is,
IN: front case fan, cpu fan through heat sink
OUT: back fan, top fan
During testing, I found that leaving the case open was worse than stock cooling. Without a specific path to follow, the fans don't do any good and the air stagnates. So, on with the cardboard side cut out to receive the CPU fan tunnel.
When I'm satisfied that I've got the best layout, I'll cut the original metal sides to fit the new fans.
With this set up I get these temps (with the server running):
CASE: 82o
CPU: 105o
This is ~9-10 degrees cooler than the stock setup on its best day. The heat sink feels cool now, so I think I've reached the limit of what can be done with improved airflow alone. To go cooler, I'd have to replace the heat sink with a better one made from copper. These temps are quite good for a computer under load, so there's no real reason to go any farther, other than because I can!
The four-pack of 80mm fans was $15 and the 60/80mm adapter was $4, so obviously I haven't spent much money. If you want to make your fans more finger-friendly, you can buy grills with the fans.
In my estimation, the most beneficial additions where the front and top fans, and removing the grill restrictions on the back fan.
All extra fans should be plugged into the power supply, NOT the motherboard. The mother board probably supplies your original fans, but the additional current of extra fans may be too much for it.
