At the SC07 supercomputing conference (image gallery) in Reno Nevada, IBM previewed the liquid cooled 32-core 4.7 GHz System p 575 Power6 supercomputer last night at the opening gala. What sets this server apart is that it actually returns to a water cooling system which were common in older mainframes but shunned in recent years. This 32-core 4.7 GHz Power6 system with up to 256 GB memory (64 4GB FBDIMMs) is designed to compete with systems based on 64-core Intel 1.6 GHz Itanium 2 systems.
This "big iron" server actually fits in to a 2U chassis though it's much deeper than the normal 2U server and that doesn't include the water pump and power distribution system which feeds DC power to 14 of these servers in a single rack. The server uses around 4000 watts of power. Realistically these can be thought of as 4U servers if we were to compare it to conventional x86 servers that have the cooling and power supplies self contained.
These systems are ideal for computational problems that require massive amounts of memory and processing power which cannot easily or are sometimes impossible to split up across smaller servers. To put the capability of this 32-core Power6 system in to perspective, a 16-core Power6 system is approximately 2.2 to 3.8 times faster (SPECint_rate2006 and SPECfp_rate2006 respectively) than the largest/latest Intel 16-core "Tigerton" x86 server. Since SPEC scores for the brand new 32-core system isn't available yet, I had to compare to the 16-core version but note that these systems scale fairly well so it's conceivable the performance of the 32-core will be close to double. Of course you should expect the cost to be many times more than that because price is often the square of the performance multiplier in the high-end market.
The previous generation System p 575 based on the Power5 used the two massive air blowers in the front of the chassis to cool the entire system including the memory and CPU. But with 16 4.7 GHz Power6 processors shoved in to a very dense environment, a more exotic cooling solution is used to efficiently cool this beast. The massive twin air blowers are still used to cool the system and hot FBDIMM memory components.