Fans are easy to install, but noisy and limited in heat/power capacity. With 130W+ CPUs like Intel's Kentsfield when overclocked - even the top ones, like Zalman 9700, hit the ceiling quickly.
Water systems have substantially greater cooling capacity, but at the cost of installation, and complexity - pumps, radiators and a zillion of pipes, not to mention leakage scares and so on. Also, since there is no fan present at the CPU socket location, the VRM, North Bridge and memory areas have to be cooled ususally with a fan.
Evercool's Silver Knight tries to bridge the gap - it's the first heat sink and water cooler combo for the CPU that we know of. The box is a bit larger than the largest standard cooler, the abovementioned Zalman, and much larger than the similar-named Silent Knight from Asus (a normal copper heatsink). The device itself looks bulky, but is surprisingly light - while the four heat pipes are copper-based, the fins are of aluminum, and the water cooling side part is, well, plastic.
The combo could function as a standard heatsink even if, for some reason, the water cooling portion fails - the heat pipes and fins are ventilated by a large side fan which channels the air towards the outflow case fan above the I/O shield. Water cooling tubes circulate the fluid to and from the heat pipes, providing a 'self-contained water cooling' as Evercool calls it. So, in theory, you'd have a combined air and water cooling power.
The reddish coolant is pre-filled, and the cooling tubes bringing it to the ends of the heatsink's heat pipes are all pre-fitted and set. All you need to do is to fit it on the Intel or AMD CPU socket through an adapter, just like any large standard heatsink, and connect the 3-pin CPU fan cable - that's all.
Is the new cooler more efficient than the usual suspects? I set it up on a challenging platform - an 130 W+ Intel Pentium XE P965, the very last OutBurst of the NetBurst. It's a hot dual-core dual-die 3.73GHz 1066 FSB monster, running at the Intel D975XBX board, and from the very start I set it overclocked to 4GHz with 1333 FSB and 12X multiplier (not an easy feat in any case for Intel's Presler series CPUs). The same ran with Thermaltake Golden Orb II just before that, with CPU reaching 67 C even in BIOS hardware monitor. With Evercool's Silver Knight, the temperature at the same settings went down to 49 C - not bad, but not that much better from Zalman 9700, where it was at 52 C. On the other hand, Zalman's air cooler costs as much as many water cooler, so I can't complain here.
While keeping the same 1.275v CPU input voltage, I managed to bring the speed up to 4.28GHz with a 1428GHz FSB - the CPU still ran at around 54 C in the hardware monitor, but Windows couldn't boot at all. After I replaced Intel's lacking North Bridge heat sink with Cooler Master Blue Ice II (an all-copper thingie with a fast fan) the system proceeded to boot, but Windows boot success was truly erratic - by this, I mean you're lucky if you get it up every other time.
When I changed the FSB back to 1066 and left the CPU running at 4.27GHz using a 16X multiplier, the system was fully stable in running Windows, and the CPU was showing around 53 C in the hardware monitor - not bad at all, compared to 51 C of Corsair COOL high end cooler, and 59 C of Zalman 9500 at the same CPU and speed. With the integrated fan speed switch, I could reach near-silent operation, which didn't matter to me as I don't play music on benchmark systems, but may be important for the MP3 buffs. Also, the performance on the P965 can give you a good indication of how the thingie will perform on the quad-core Kentsfield, since that chip has similar thermal and power demands.
Overall, this new kid on the block has got interesting technology, decent performance, very quick installation (10 minutes plus 5 minutes for taking the mobo in and out to mount the bottom supports) and fits well to the board. A full-copper version with a faster fan and a bit more coolant would be welcome as well Now, if they could just improve the screw tightening system - the screw locations are hidden deep under the heat sink, and, on mainboards with arrays of tall power circuitry around the CPU sockets, it is near impossible to make use of that hexagonal driver provided to actually mount and tighten the screws. The fingers got to do the job, small enough to fit in, and thick-skinned enough not to be shredded by sharp VRM heat sinks. I managed it, anyway, and could still type this story..."?