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Corsair Hydro H70 Liquid CPU Cooler E-mail
Reviews - Featured Reviews: Cooling
Written by David Ramsey   
Monday, 07 February 2011
Table of Contents: Page Index
Corsair Hydro H70 Liquid CPU Cooler
Closer Look: Corsair CWCH70
Corsair CWCH70 Detailed Features
Heatsink Test Methodology
Testing and Results
Final Thoughts and Conclusion

Closer Look: Corsair CWCH70

The 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.



# Idea.Succellus 2011-02-08 02:08
You could put a symbology of all your awards so newcomers know how good the product is according to the award.
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# RE: Idea.Olin Coles 2011-02-08 08:26
The final score is a 10-point value, and should be an easy indicator for newcomers.
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# RE: Corsair Hydro H70 Liquid CPU CoolerRobert17 2011-02-08 05:14
I purchased an H50 last year and have it configured to exhaust outside the case and find it's performance acceptable on a day-to-day basis. It's certainly an improvement over the stock CPU coolers, and reasonably priced for that uptick.

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.
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# RE: RE: Corsair Hydro H70 Liquid CPU CoolerDavid Ramsey 2011-02-08 11:46
A push-pull configuration probably won't double airflow, but it will certainly help compared to a single fan. For "thin" radiators a single fan of "x" CFM will probably provide more airflow than a push-pull config where each fan is "x/2" CFM, but I think this would not be the case with the H70's double-thick radiator, which offers much more resistance to airflow.
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# h50 performs betterBunzing 2011-02-08 06:30
I switched motherboards a couple of weeks ago and wrecked the backplate of the h50 when I had to take it of. Corsair for some reason put superglue on it and it didn't come of without force. So I thought I'd buy an h70 and get corsair to send me a new backplate and sell the h50. Don't think I'll be getting the new backplate though since corsair won't respond to emails.

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.
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# RE: h50 performs betterDavid Ramsey 2011-02-08 11:47
I'm surprised the H70 is turned in higher processor temps than your H50. If you feel ambitious, it would be interesting to remove your Cosmos' side fan, put the H70 in the back, and see if that makes a difference.
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# RE: RE: h50 performs betterBunzing 2011-02-13 09:33
I'll try that when I have the time. I'm curious to see if that makes the difference.
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# RE: RE: RE: h50 performs betterBunzing 2011-03-01 03:22
Well, I placed the h70 in the back with the side off and it did shave the temps a little when it comes to case temperture but the cpu only dropped like 1c. Now i've got my h50 in the back with a thermaltake iscg fan as a second fan at 1000rpm and I have to come back on the temperture as it does run a around 4 to 5c of degrees higher than the h70 (nothing like the diference i've seen in most benchmarks where it's more like 10c). For me the amount of decibels the h50 runs lower on is the deciding factor. The temps never hit 45c, so i'm good.
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# Area mattersRealNeil 2011-02-08 06:57
For better heat dissipation they should have gone for more radiator surface area instead of a thicker radiator. A 120mmX240mm area would cool more efficiently. I realize that it would affect the fitment into a number of cases, but many cases have incorporated a spot for two 120mm fans on the topside already. Since heat normally rises, placement of such a radiator at the top of a case, exhausting the hot air through the top would just work better. I have an Asetek-LCLC (low cost liquid cooling)and a Corsair H50 here, (both are MADE by Asetek, and both are identical too) I have them in push/pull with high flow and quieter fans on each of them. They are excellent cooling solutions for my two i7-870's, both running @3.93GHz.
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# RE: Area mattersDavid Ramsey 2011-02-08 11:52
Heat-- well, heated fluids-- do indeed rise, but even the feeblest fan will provide an order of magnitude more air flow than the convection currents off a hot radiator, so I don't think radiator positioning will make a noticeable (or even measurable) difference in performance (although another commenter here who's mounted his H70 rad at the top of his case is getting worse performance than with his H50 mounted at the back, which is the opposite of what you'd expect).

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.
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# Koolance erm-2k3u + cpu-350 + ocz freezeJuanPabloC 2011-02-08 13:01
my i7 920 @ 2.8ghz works at 21°c with 11 blocks, at "full" load (WinRar benchmark test)cpu never goes over 28°c. (43°c at the cores)... measured with HWMonitor from

60°C ? ... at the cores?
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# RE: Koolance erm-2k3u + cpu-350 + ocz freezeOlin Coles 2011-02-08 13:14
That's because you're using a very weak test, Juan. Plus you're comparing apples to oranges. Why not download the free AIDA64 trial and run the CPU System Stability Test tool?
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# not goodcactus 2011-02-08 23:00
It surprises me that this cooler gets a good wrap from reviewers. As the benchmark shows a highend air cooler performs better than a H70 even with its high speed/loud fans.

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.
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# Helpful All in one Liquid Cooler ReviewJohn Darcy 2011-02-11 03:48
Thanks for the tips and dremmel tips that are actually tried and tested. I am sometimes fearful of attempting too many cutting operations,or any at all for that matter lest I do irreparable damage to something. It isnt as if I still couldnt , however i enjoy the reviews which actually do make alterations out of the box to make something work better.
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.
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