A nice noise/performance tradeoff — Joe
SUMMARY: A very effective compromise balancing noise and performance.
The good guys at Evercool sent over their Evercool CUD-725 to test out. This is an all copper heatsink sporting 24 fins. The fins
are about as thick as three index cards. Airflow through the fins is quite good, as they are about 2mm apart. The bar which appears to run through the fins is not one piece – each fin has two small cylinders attached to it as a spacer. The base
is quite smooth (actually polished) and flat – a very nice job.
The fan is a 70 x 25mm unit (Evercool EC7025HH12C) rated 42 cfm @ 4200 rpm. I found it to be tolerably quiet – I measured its noise at 63 dBA with a Radio Shack sound meter 8″ from the fan’s intake, substantially less than a Delta 38 (about 69 dBA). It’s also safe to use a motherboard fan header – it draws 4 watts.
The clip engages one lug of the socket and requires a screwdriver to mount. The slot for the screwdriver tip is not as wide as I’ve seen on some others, so make sure the blade is narrow enough to fit into the slot – slips can be fatal to the motherboard.
In summary, a beefy all copper heatsink with a tolerable 70mm fan.
The Evercool CUD-725 was first tested on the CPU Die Simulator which gives results that are unaffected by motherboard influences. I then tested it on an Iwill KK266+ and Shuttle AK31, modified to read AMD’s on-die diode, as an example of what users might see on their systems.
| Heatsink | Die Temp | Ambient Temp | Delta | C/W |
| Evercool CUD-725, 77.3w | 49.2 C | 19.8 C | 29.3 C | 0.38 |
| CPU/Motherboard | CPU Die Temp | Ambient Temp | Delta | C/W | CPU Back Temp |
| Palomino 1200, Iwill KK266+ | 37.0 C | 22.8 C | 14.2 | 0.26 | 39.5 C |
| XP @ 1467, Shuttle AK31 | 39.7 C | 20.3 C | 19.4 | 0.30 | 33¹ C |
¹In-socket thermistor per MBM
C/W = Delta / CPU Watts
Interpreting C/W: For every watt the CPU radiates, the heatsink will cool the core by the (C/W x watts) plus ambient temp. For example, at an ambient temp of 25 C, a C/W of 0.25 with a CPU radiating 50 watts means that the CPU core temp will be 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 Evercool CUD-725 in the middle rank of heatsinks tested to date (Heatsink Ranking).
All told, the Evercool CUD-725 is a very good performer with tolerable noise levels – a very nice performance/noise tradeoff.
Thanks again to Evercool for sending this our way.
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