Asetek is well known for making liquid cooling solutions for cooling PCs, with their designs being incorporated by many manufacturers such as Dell.
Recently they have made a prototype PC with a Intel Core i7 920 processor and a Nvidia GTX280M dedicated GPU both of which are liquid cooled. Like an iMac the AIO prototype has no desktop tower, with all the hardware integrated into the back of a 24inch LED display.
Driving more performance from within thin profile computers such as all-in-ones, 1U servers, blade servers and performance notebook PCs means increasing thermal density," notes Steve Branton, Director of Marketing at Asetek. "This all-in-one prototype demonstrates one way that liquid cooling overcomes the thermal challenges that arise when squeezing high performance into thin form factors. The engineering team at Asetek continues to innovate and expand the liquid cooling options for cooling thin form factor PCs.
Here's a video to make things simple:
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