The Arkua 6149 uses a small 10mm thick 60mm fan rotating at a low RPM so it is naturally a pretty quiet heatsink. If you really want to hear the difference this fan makes, go to our review of the Arkua 6258 and compare the Acoustic sample with this one of the 6149.

Synthetic Temperature Test Results: *Ranked according to 100W small interface die test results.

1U - FrostyTech Synthetic Temperature Test Platform Results
	Mfg.	Model	Ambient Temp.	27mm large copper block	15mm small copper block		27mm large copper block	15mm small copper block	Thermal pad	No. Fans	Fan Noise	Clip force
				50W	50W		100W	100W
1	Arkua	6149	23.2	50.9	53.1		81.2	81.4	silver	1	low	med
2	Dynatron	DC1206BMR	23.8	51.0	56.5		80.6	86.8	silver	1	med	stiff
3	Spire	5R057B1M3R	23.0	44.9	69.7		66.4	89.7	silver	1	med	easy
4	Vantec	FCE-6010	25.6	70.7	72.4		111.3	116.9	silver	1	low	stiff
				50W	50W		100W	100W

The initial temperature results with the 1U coolers are significantly higher than with other coolers we have reviewed. Let's face it, 1U coolers are a lot smaller, and use substantially lower powered fan to do the same job as their larger desktop cousins.

1U - Rise Above Ambient Temp. (c)
	Mfg.	Model	27mm large copper block	15mm small copper block		27mm large copper block	15mm small copper block
			50W	50W		100W	100W
1	Arkua	6149	27.7	30.0		78.0	58.2
2	Dynatron	DC1206BMR	27.2	52.7		56.8	63.0
3	Spire	5R057B1M3R	21.9	46.7		43.4	66.7
4	Vantec	FCE-6010	45.1	46.8		85.7	91.3
			50W	50W		100W	100W

There are some odd temperature differences between the large interface die template and the small interface die, but they aren't really important. Although we have included the results on the large interface die, none of these heatsinks is intended for use with a heatspreder toped processor like the Pentium 4 which might actually be in a server at this time. Several of the heatsinks were intended for use on older PGA processors, but they aren't being used much these days so we will simply concentrate on the small interface die results.

As you can see from the list of reference coolers here, the Arkua 6149 performs the best under the conditions we described previously. Note that the copper heatsinks handle the large interface die much better than either of the two aluminum heatsinks. In any case, it would seem as though Arkua have a fairly good 1U solution to offer relative to the other reference coolers here.