Why gpu servers don't use watercooling?

Super cheese sandwich

I thought that watercooling was the most effective way to cool a gpu. Almost all the gpu servers (image attached) don't use watercooling. The envirioment in these racks are super hot and they use the reference model (what is worse). I'm not talking about Tesla and Quadro that are build with better quality for this kind of envirioment. They use 980ti and titans. WHY? WHY? 

 

Thanks!

SixDs

"I thought that watercooling was the most effective way to cool a gpu."

Well, not necessarily. Some water cooling systems are more effective than others, just as some air cooling systems are more effective than others, so blanket comparisons are prone to qualification. What we do know is that water cooling systems tend to be more complicated than air cooling systems, with more potential points of failure and potentially higher maintenance. You will notice in your image the number of fans in that device - eight fans in paired arrangements. Typically, rackmount devices use multiple, relatively small fans spinning at high rpm's to move lots of air. Very noisy. Not an issue in a server room, but undesireable for most home uses. Server rooms are also often actively cooled, to keep ambient air temperatures low and aid with cooling.

So, to answer your question, I would guess that it is cheaper to use air cooling and easier to effect maintenance and repairs. Keep it simple. Of course, a water cooling system could experience a catastrophic failure that could take out more than just your GPU's, so risk management could also be a factor.

Super cheese sandwich

Doubt solved! Thanks SixDs 

fredmusic

The other reason is space, 8 cards in the same chassis has little room for the tubing.  A proper heat pipe cooler can be very good, but stock products don't usually come with high end coolers.

RobotHeadArt

SixDs said:

Server rooms are also often actively cooled, to keep ambient air temperatures low and aid with cooling.

And the server room itself could be cooled using a chiller (https://en.wikipedia.org/wiki/Chiller) which is using cooled liquid to remove heat from the datacenter. 

Blastedlabs

They keep the room the servers are in at 60 degrees.  Basically a fridge.  Water or oil can cool faster, because it's denser, but very cold air is good enough.  Then the system for cooling the room is very efficient.