SUMMARY: An excellent heatsink for Intel's hotties.

The good guys at Thermalright were nice enough to send their latest heatpipe heatsink, the Ultra 90 for P4 and Intel 775 cooling for a test spin. This unit features six heatpipes in a "U" shaped configuration.

Included with the parts that ship with the unit are fan clips for a 90 mm fan:

Mounting is straight forward - there are two clips which engage the P4 retention bracket. The preferred mounting procedure is to engage the two clips at the back end of the heatsink and then rock it forward to engage the retention bracket. The LGA 775 bracket is also a no-brainer - engage the socket lugs and rotate the lever arm - done.

The base is well finished; I used the Poor Man's Flatness Test on it with good results:

Rotating the base 90º:

Overall the Ultra 90 is well finished and attractive.

The Thermalright HR-01 was tested on an Abit AI7 motherboard with a modified P4 Motherboard Test Platform with a modified P4 3.2E to read CPU case temps. The Ultra 90 was tested with a Delta 92 mm fan at various fan speeds to give a range of results.

Heatsink	CPU Case Temp	Ambient Temp	Delta	C/W	MBM Temp
Ultra 90, Delta 4739 rpm, 77 dBA²	32.3 C	19.2 C	13.1	0.13	44 C¹
Ultra 90, Delta 3512 rpm, 68 dBA²	33.1 C	18.6 C	14.5	0.14	45 C¹
Ultra 90, Delta 1989 rpm, 52 dBA²	36.4 C	20.2 C	16.2	0.16	48 C¹

¹MBM on-die temperatures.
²50 dBA measured 8" from the fan intake corresponds to about 30 dBA measured 3 feet from the fan, a very quiet noise level.

As the test platform is different, results are not comparable to other heatsinks tested. However, I did test Thermalright's XP-90C with the same platform with the following results:

Heatsink	CPU Case Temp	Ambient Temp	Delta	C/W	MBM Temp
XP-90C, Delta 4730 rpm, 77 dBA²	31.5 C	19.9 C	11.6	0.11	45 C¹
XP-90C, Delta 3460 rpm, 68 dBA²	32.5 C	19.6 C	12.9	0.12	46 C¹
XP-90C, Delta 1950 rpm, 52 dBA²	35.1 C	19.6 C	15.5	0.15	48 C¹

¹MBM on-die temperatures.
²50 dBA measured 8" from the fan intake corresponds to about 30 dBA measured 3 feet from the fan, a very quiet noise level.

Comparing the two on the same platform shows that the Ultra 90 lags slightly behind the XP-90C by about 2ºC on average - not bad territory! Results place the Ultra 90 in the topmost rank of P4 heatsinks tested to date (Heatsink Ranking) based on its comparison to Thermalright's XP-90C.

Thermalright's Ultra 90 is an excellent heatsink for Intel's hotties. Using the Ultra 90 with a variable speed fan controller seems the best approach for all-around use.

Thanks again to Thermalright for sending this our way. The Ultra 90 is available from The Heatsink Factory.

Disclosure: Joe Citarella has a financial interest in a company developing thermosyphon products for electronic chip cooling.

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