Cooler Master IHC-H71

Very good performance for P4 CPUs though noisy — Joe

SUMMARY: Top rank P4 cooling, although noisy.


Size: 83 x 70 x 75mm high; Weight: 740 gm; Fan: 46 cfm @ 6000 rpm.

The good guys at PHAMComputer were nice enough to send over a Cooler Master IHC-H71 to check out. This is the P4 version of the Cooler Master HHC-001, which performed very well on Socket A/370 platforms. As P4 popularity picks up, we’re seeing some very competitive cooling solutions coming to market – about time!

Compared to the HHC-001, the P4 version is longer and wider – the heatpipe is less visible in this version. The fin’s surface area is greater compared to the Socket A/370 version.

The base


is flat but not particularly well polished – lapping (Hoot gained 3 C by lapping the HHC-001) is definitely an option and may yield some benefit.

Looking edge-on,


you can see how the heatpipe comes up from the base and is cooled by the fins. The heatpipe pops out


on the other side.

The mounting mechanism uses articulated lever arms on both sides to clamp the heatsink to the CPU using the standard P4 retention base – very easy to latch onto the base. However, as I moved the lever arms to lock the heatsink into place, it required a fair amount of force to close them. I hesitated because I felt that the force required would snap the lever arms – one flexed more than I liked; they didn’t snap, but be warned on this point.

The fan is an YS Tech Model #FD1270259B-2F – a 70 x 25mm unit rated at 6.24 watts, 46 cfm @ 6000 rpm. I measured its noise at 67 dBA with a Radio Shack sound meter 8″ from the fan’s intake, close to a Delta 38 (about 69 dBA). I normalized these readings to what you might hear 3 feet away.

In summary, a good adaptation of the HHC-001 heatpipe to P4 use with a mounting system that could be beefed up.


The IHC-H71 was first tested on the CPU Die Simulator which gives results that are unaffected by motherboard influences. I then tested it on an Lucky Star 4A845D with a modified P4 1500 to read CPU case temps, as an example of what users might see on their systems.


Die Temp
Ambient Temp
IHC-H71, 6570 rpm, 53 dBA
45.4 C
21.0 C
24.4 C
IHC-H71, 6185 rpm, 51 dBA
46.4 C
21.3 C
25.1 C
IHC-H71, 5415 rpm, 49 dBA
47.0 C
21.3 C
25.7 C
IHC-H71, 4500 rpm, 43 dBA
48.2 C
21.0 C
27.2 C
IHC-H71, 3200 rpm, 38 dBA
51.5 C
21.2 C
30.3 C

TEST RESULTS – Motherboard

CPU Case Temp

Ambient Temp



MBM Temp

Lucky Star, P4 1500, 6200 rpm

31.0 C

21.5 C



27 C¹

¹On-Die temp per MBM

Delta = CPU temp – Ambient Temp
C/W = Delta / CPU Watts

Interpreting C/W: For every watt (CPUw) that the CPU
consumes, the HSF will limit the CPU’s temperature rise to (C/W x CPUw)
plus the temperature at the HSF’s fan inlet. For example, at an ambient temp of 25 C, a C/W of 0.25 with a CPU radiating 50 watts means that CPU temp will increase 50 x 0.25 = 12.5 C over ambient temp, or 37.5 C. The lower the C/W, the better.

Die Simulator results place the IHC-H71 in the top rank of heatsinks (Heatsink Ranking), although noise is on the high side. Throttling the fan back to something around 4000 rpm (about 7 volts) yields more tolerable noise, although it costs about 5 C in cooling (at 100 watts).


Top rank cooling with top rank noise.

Thanks again to PHAMComputer for sending this our way.

Email Joe

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