Megahalems vs. TRUE Heatsinks: Stock Comparison on Overclocked i7 Platform

Two top performers in air cooling are the  Prolimatech Megahalems and the Thermalright Ultra 120 Extreme (TRUE).  This is an “out of the box” comparison, and is strictly to test the thermal performance of these two heat sinks with stock base and mounting with no modifications. The comparison was done in an environment that is as controlled as possible without having laboratory conditions or equipment.

Test Setup

Both heat sinks will be tested on my bench in open air. Ambient temperature was measured in the room where the tests were performed.

If you want a rough breakdown of fan specs at each voltage setting just divide into three equal divisions, keeping in mind that this controller only gives 11.3v rather than a full 12v at max setting:

Fan voltages were measured with a multimeter. The rest (RPM, airflow, pressure, noise) can only be estimated, but from what I can tell it’s pretty darn close.

• The Heat Sinks:
  • 1 TRUE Black (Original)
  • 1 Prolimatech Megahalems
• Fans:
  • Sanyo Denki San Ace 109R1212H1011
    • shrouded 25mm, push pull added later on for 4.4 and 4.6 GHz stops
    • Current: 0.52A
    • Watts: 6.24
    • RPM: 2600
    • Flow CFM (Max): 102.4 CFM / 2.9 cu meter[m3]
    • Static pressure (in. H20): 64.7 Pa (6.6mm)
    • Noise (dBA): 39.0
• Controller:
  • Sunbeam Rheobus 6 Channel
• TIM:
  • AC MX2

Test Methodology

• Each heat sink was tested from 8 (7.54)v to 12 (11.3)v fan settings in 2V increments.
• Each heat sink was tested for 10 minutes at each fan speed with Prime95 small FFTs, with resulting core temperatures recorded as measured by Real Temp 3.36
• For graphical purposes, temperatures have been averaged. I’ll warm things up prior to the 8V test to create the same conditions the rest of the fan setting tests will see.
• After the single push fan test, each heat sink was fitted with a second fan for push/pull testing.
• Each cooling setup was tested at the same ambient air temperature of 21C. Temperature was measured before and after each heat sink was tested to confirm a consistent temperature.
• Each heat sink will be tested on an un-lapped i7-950 @ 4.0GHz with a vcore of 1.264v.

Prolimatech Megahalems

Temperature Results:

Thermalright Ultra 120 Extreme (TRUE)

Temperature Results:

Overall Results

Pretty much as I expected really, a close match. Both coolers performed very well. However, there are a few things I’d like to mention:

• The base on my TRUE is very flat. For a stock TRUE out of the box, this would tend to be the exception rather than the rule. I think that pitting the Megahalems against any other stock TRUE would likely yield different results.
• The mounting mechanism for the Megahalems, while well designed and easy to install, did not provide as much tension as I’d like. From what I observed (see TIM spread pictures) the TRUE did provide more stock mounting tension at max. However, both coolers did get a good even spread and adequate thermal bond.

Further Testing

Well, TIM application method definitely makes a difference with the Megahalems. I wasn’t expecting quite this much though. The TRUE was not tested with the line method, as I know this heat sink does not take well to it at all (typically adds ~5C).

Some interesting information has come out here I think (and forgive me if this is already common knowledge to some):

• The TRUE seems to be superior at lower fan speeds. I find this odd since the original TRUE has a denser fin pattern than the Megahalems.
• The Megahalems shows a much larger temperature spread between fan speeds (in particular between 8v and 10v). Whereas the TRUE seems to best it at low fan speeds, the Megahalems quickly steps things up, and even passes the TRUE as fan speed increases to ~2000RPM.
• With a single fan configuration, the TRUE and Mega seem to perform the same at the max fan speed setting of ~2400RPM. In push pull, the Mega seems to outperform the TRUE after ~2000RPM.
• Please keep in mind, that even though the Megahalems is leading the TRUE in this test, we’re talking about less than a degree throughout the fan speed range. The larger differences are actually seen while comparing the same heat sink in single fan vs. push pull configurations.

– Baditude_df