| Corsair Hydro H70 Liquid CPU Cooler |  |
| Reviews - Featured Reviews: Cooling | |
| Written by David Ramsey | |
| Monday, 07 February 2011 | |
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Closer Look: Corsair CWCH70The Corsair Hydro Series H70 comes in a rather large box. You know you're buying something impressive, even if exactly what it is isn't immediately obvious.
Inside the box are the neatly arranged components...
...which are the pump and radiator assembly, two 120x25mm fans, a manual, an installation instruction sheet, and mounting brackets and screws. The H70 comes with everything you'll need for Intel Socket 775, 1155/1156, 1366, and AMD sockets AM2/AM2+/AM3. Also included are a 3-pin "Y"-cable that allows you to run both fans off a single motherboard header, and two "step-down" resistor cables that drop the fan RPM from 2000 to 1600.
The H70 is different from its H50 predecessor in several ways: the radiator is twice as thick, there are two fans instead of one, and the pump unit is smaller. A lot smaller, really: compare the H70 pump (on the left) to the H50 pump (on the right). You might wonder if the newer, smaller pump has the same flow rate as the older, larger pump, but since neither Corsair nor OEM Asetek (who manufactures the H70 for Corsair) publish this information, there's no way to know.
The H70 retains the same mounting mechanism as the H50: a thin metal retaining ring with interior notches is secured to a back plate by four screws. The pump has notched edges; after mounting the bracket and installing the screws part-way, you insert the pump from the top and rotate it a few degrees so that the notches on the edge of the pump slide under the notches on the inside of the retaining ring. Tightening the screws will clamp the retaining ring against the pump and press it firmly against the processor. You'll actually have to assemble a bespoke bracket from the components included: four metal screw inserts must be positioned in the correct 4 (out of 12) possible places in the Intel back plate, and the retaining ring requires that 4 screws be inserted into the proper plastic offsets, which are then snapped into the retaining ring. All told, 14 different pieces comprise a complete mounting system, and paying attention and assembling the right parts correctly for your application will pay off.
The original Asetek water coolers used a much more robust mounting system. Compare the older mounting system on the left, which uses a 1/8" steel base plate and a thick plastic retaining ring secured by compression screws, with the current mounting system that uses a plastic base plate and thin sheet metal retaining ring, the "springiness" of which provides the clamping pressure. Clamping pressure is an important part of overall heat sink performance, and the best performing air coolers like the Polimatech Megahalems and Thermalright Venomous X have very substantial mounting systems. 
I suspect the older mechanism provides higher clamping pressure that might improve performance, but the side-mounted swivel hose fittings on the H70 pump mean that a little Dremel work would be required to find out.
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Comments
I'll add to your note regarding the 'secret' pump performance. Besides the fluid flow, the fluid itself makes a difference and custom systems certainly have another advantage here. Different fluids and additives can increase heat transfer by decent margins. So if one is involved in serious overclocking, an open system has many advantages. But the simple and sealed packages such as the ALC and Corsair offerings are, as you said, a reliable, quiet, affordable, and easy way to increase heat displacement from the CPU.
Also note, the dual fan, push/pull configuration mounted to the radiator doesn't necessarily increase the CFM across the radiator by doubling the air flow (think of a fan as a pump for the fluid named 'air'). The same air moves through one fan, across the radiator, and then through the second radiator, fan speeds being equal. The air doesn't 'hover' around the radiator but is drawn more efficiently across the fins, and consistent pressure is maintained. To move more air, the fan speeds must be increased. Just as with any fluids, to increase flow, pumps must increase the fluid pressure. Adding more in-line pumps (fans) that all run at the same RPM doesn't increase flow, just maintains consistent pressure.
The h70 however has to be placed in the top of my cooler master cosmos s because otherwise it would interfere with the side intake fan. It runs on 1600 rpm and makes a lot more noise then my h50 (also had two fans) and runs 5C higher then the h50. Both are configured as exhausts btw.
I don't understand what causes this difference. Offcourse the sound is understandable since I had two of my own thermaltake iscg fans on it running at 1000 rpm! But still the h70 with 1600 and bigger radiator is 5C above the h50 with 38C in idle and around 42c when playing games.
If or when I get the backplate I'll do some testing wether or not there still is a big difference when I put it up in the same configuration and use the same fans as the H70.
A double-thick 120mm radiator offers the same surface area as a single-thickness 120x240mm radiator, although I think the latter would probably have a performance advantage due to better air flow.
60°C ? ... at the cores?
A highend aircooler will operate cooler even with a(good)silent 1200RPM fan like the Scythe S-Flex. I know this because i have one and its virtually silent on a Thermalright cooler. I have tested many, many fans and only the best 1200RPM fans are virtually silent, fans spinning at 1600/2000 RPM are just ridiculous.
Why would you put up with noise and pay a lot more for H70 when you can have a cheaper and virtually silent high end cooler. I can only assume some people have never experienced a silent system or know what is possible or have been sucked in by "water" cooling marketting.
And before anyone says "You can run the H70 with 1200RPM fans" the H70 suffers badly with fans at that speed and you can add 10 Degrees to temps.
I have a gpu which seems to make in non silent even at its factory de tuned super low power usage rates. as soon as it gets beyond 32% it is audible to my old ears and after 34% it is noisy. I have a good aftermarket cooler on one 5870 and it is quieter but not silent. so the notion of a silent system as far as the cpu cooler goes is out. But, there are some good 'quiet' fans which push a fair amount of air enough dramatically reduce my Phenom II 965 in the hot summer. I do not think these liquid all in ones ready for me and my price point as yet. It is good to know how much progress is being made. I have used enough of the well reviewed air cooler/heat sink types and changed fan with good sale silent fans or 100+ cfm represented ones with 'some' noise.
i enjoy the input here on this side of the review as well for the reservoir of experience and info.
your efforts are greatly appreciated here.