Thermalright XP-120: 1st 120mm fan CPU heatsink

ON THE TEST BENCH

Not ever having seen or used any other 120mm heatsink, I compared the XP-120 to my sort-of-reference Zalman 7000AlCu heatsink. I used the same processor that I've been using in all my heatsink tests, a Pentium 4, 2.4C. It may not put out as much heat as a new Prescott, but using this processor will allow me to directly compare the performance of the new XP-120 against all the other P4 heatsinks that I've tested during the past year.

I was not able to test the XP-120 in full accordance with the standard SPCR testing method, which calls for the HS to be used with SPCR Reference 80mm Panaflo L1A. Nothing but 120mm fans will fit. I decided to test several different types of "quiet" 120mm fans on the XP-120, to get a good feel for its performance.

Ye Olde Test Setup.

HS TEST PLATFORM & PROCEDURE

The P4 HS test platform is an open system not enclosed in a case.

Intel P4-2.4C Northwood core - Maximum power is 66.2W.
Intel 875PBZ motherboard - Intel 875P Chipset; on-die CPU thermal diode monitoring
ATI Radeon 7500 passively cooled video card (AGP)
Mushkin PC3200 Level II - 2 x 512MB DDRAM
Seagate 80GB Barracuda IV hard drive
Seasonic SuperSilencer 300W (rev A1) PSU modded with 5V Panaflo M1A
Arctic Silver Ceramique Thermal Compound
Two-level metal platform with rubber damping feet. Motherboard on top; other components below.
CPUBurn processor stress software
Motherboard Monitor 5.3.4.0 software to track CPU temperature and fan speed

Each heatsink was cleaned and installed on the test system as per the manufacturer's and Arctic Silver's instructions. Prime95 was then run for 8 hours to verify system stability and cure the Ceramique. The system was then shut down and not restarted until the next morning when the actual testing was done. The system was allowed to cool between tests for 30 minutes. Each test was run for 30 minutes even though all temperatures generally stabilized within 15 to 20 minutes.

Each heatsink was retested three times on consecutive mornings to check to the consistency of the results. All results were within 1-2°C of each other and the average readings are included in the charts.

Ambient temperature was measured at 71-72°F (22°C) over the entire series of tests. No tests were run unless the ambient temperature was at that reference level.

* All temperatures in degrees Celsius.
* Diode: Reading from P4-2.4C CPU diode via Motherboard Monitor.
* Temp Rise refers to the difference between ambient temperature and the diode reading. .
* °C/W refers to the °C of temperature rise per watt of heat dissipated by the CPU.

RESULTS

I tested the heatsink with each of the fans at 12V, 7V and 5V, blowing down on to the heatsink as well as up.

At 12 Volts, all the fans cooled spectacularly well, but all were too noisy for serious consideration by SPCR readers. The Evercool was the loudest, followed by the L1A Panaflo, then the OEM Panaflo with the Globe coming in as the quietest. None of them were particularly obnoxious at 12V, especially when compared to a comparable 80mm or 92mm at that same voltage. All fans were initially tested by mounting them in the typical "blowing-down-on-the-heatsink" orientation but when I was finished I decided to retest all of them mounted in the "sucking-up" orientation. All cooled virtually the same in either orientation. All fans on the XP-120 also performed better than the standard Zalman 7000AlCu, from 3°C to 7°C. All the 120mm fans were a bit quieter at 12V than the 92mm Zalman fan at 12V. The Zalman fan had a higher tone to it's whine as well as more wind noise.

AT 7 Volts, all the fans cooled great, in either orientation, with the Evercool performing the best, but it was also the noisiest. The L1A had a bit more whine and clicking noise than its OEM cousin, and the Globe was by far the quietest with very little whine or wind noise and just the slightest touch of clicking. At 7V the Zalman drew closer in performance to the larger fans, but was still louder than the bigger fans.

AT 5 Volts, all the fans were pretty darn quiet, probably quiet enough to satisfy most hard-core silent PC enthusiasts. Acoustically, the Globe was the clear winner at 5V. It was noticeably quieter than the other three fans, certainly the quietest 120mm fan I've ever heard. It had only the barest clicking sound, and only if my ears are closer than about 6" to the fan. It also had almost no air turbulence noise. The cooling ability of the XP-120 with the fans running at 5V was very impressive, especially considering the ultra-low noise. The Zalman 7000 fan was also very quiet at 5V, perhaps a bit quieter than any of the 120mm fans other than the Globe.

Note that the Globe fan cooled 4°C better blowing up than blowing down. This was the only time that a meaningful difference appeared with change of airflow direction. 41°C at full load with such a quiet fan is very impressive. The fact that it does it in the blow up direction is a nice bonus. This configuration is great for experimenting with a CPU duct, vented directly out the rear of the case, a lá Dell.

Thermalright rates the XP-120 to "P4, S478, 3.2Ghz and above", but I only tested it with the (relatively) moderate output of the 2.4C processor. We can however, use the "°C/W" numbers to extrapolate the theoretical performance of the XP-120 to any other P4 processor, including the 100+ watt P4 3.4GHz Prescott. According to Intel's "TDP" specs, the 3.4 Prescott puts out 103W. The higher "MP" power rating for the 3.4Ghz Prescott is 115 watts so we'll use those numbers to calculate the estimated maximum CPU temperature for a 3.4E running 2x CPUBurn:

Wow. Depending on how much faith you have in these calculations, it looks like the XP-120 + Panaflo L1A combination is easily beefy enough to cool the toasty P4 Prescotts, even running at a very quiet 5V setting. This is most impressive, certainly the best performance I've ever seen from a heatsink. One thing to notice is that the performance of the heatsink hardly changes from 12V to 5V. Apparently the heatpipes cool very well even with the airflow of these various fans at 5V. (Editor's Note: Keep in mind that even at 5V, these 120mm fans move more air than any quiet 80mm fan at double the RPM; they also generally have more low frequency noise than 80mm fans.)

VERTICAL VS. HORIZONTAL

Finally, the HS test platform was positioned vertically (as it would be in a tower case) to verify Thermalright's claim that positioning has no effect on performance. The results are essentially identical, so users can rest assured that Thermalright is telling it straight on this one.

Positioned vertically as in a tower case.

FINAL THOUGHTS AND CONCLUSIONS:

I'll say it again: Wow! Thermalright has hit one out of the park with the XP-120. It outperforms any heatsink I've ever used by a big margin. It is especially impressive running fans at a near-silent 5 volt setting. This would be the perfect air-cooled heatsink except for clearance issues with a few motherboards. That's not unexpected, considering the massive size. I suppose the $50 retail price might seem a little steep, but the sheer performance of the XP-120 justifies its price. The XP-120 gets two thumbs up!

Much thanks to Thermalright, Inc for the opportunity to review the XP-120.

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