I still remember the days before computers sounded like hair driers.  My first computer, the Sinclair ZX81 got hot to touch, but didn’t even include a heatsink.  There again, it didn’t have any graphics or sound either.  Even five years ago, when people were getting excited about Pentium 233MHz processors, the heatsink and fan was no bigger than the average contraption hanging off your Northbridge as you read this - and just as quiet.  As a reminder of the cool old days, take a look here.  These things pushed a whopping 3.2CFM (cubic feet per minute) of air, stuck to the processor with thermal tape and whispered along at 23dB(A) (for comparison, an average quiet living room has a background sound level of 30dB(A)).   But the Intel Pentium 233 MMX processor only dissipated 20W of power. 

By comparison the power-thirsty AMD Athlon 1400 processor produces 73.5W - the highest power dissipation of any processor yet released by AMD.  If you consider the heat that a 60W light bulb produces you can appreciate the problem (particularly as all this heat is generated in a core less than half the size of a postage stamp).  The figure below illustrates the onwards march of power dissipation with a graph of the power dissipation of AMD’s Athlon processor family versus core speed (figures taken from here and here).  Note the last three Thoroughbred B processor numbers correspond to the hypothetical dissipations that would result if AMD were to release an XP3000+, XP3200+ and XP3400+ using this core technology.  However, it seems clear that 73W of power is about as far as AMD is prepared to take any particular processor technology (the fastest Thunderbird dissipates 73.5W, the fastest Palomino 72.9W and the fastest Thoroughbred yet announced, the XP2800+, 73W).  This explains, in part, why AMD is now having such difficulty matching Intel’s Pentium 4 core speeds (the Pentium 4 Northwood 2.53GHz only dissipates 59W compared with the hypothetical 82W for a Thoroughbred running at the same core speed).  Even if you want to argue Quantispeed ratings, the Pentium 2.8GHz runs at 68.4W which remains considerably less than the 73W of the XP2800+.

 

AMD Processor Power Dissipation

So, what’s all this got to do with the quest for silent computing?  Well, heat is your processor’s worst enemy.  Excessive heat causes your processor to become unstable and the processor’s expected life is a function of its temperature.  In the extreme, a processor with no cooling will literally melt within a few seconds - giving you the ultimate in quiet computers.  As a consequence, heatsink and fans have been growing in weight and airflow at a rate that makes Moore’s Law seem quite leisurely.  The inevitable consequence of this is NOISE.

Noise is obviously a subjective term.  It seems that some people are quite happy to sit in a room that sounds like an industrial air conditioning unit, whilst others demand absolute silence.  Given that exposing prisoners to loud white noise is a standard “interrogation” technique for much of the world’s military, however, it is not surprising that many people are beginning to beg for mercy and are looking for an alternative to screaming 80mm Delta fans.  The past 12 months has seen a steady growth in products and websites devoted to offering the user a “quiet PC”.

One such company is NexusTek in The Netherlands and so when they offered to send us the new Nexus KCZ-2700 heatsink and fan offering very low noise cooling for the AthlonXP 2800+ processor, together with the Nexus NX-3000 300W silent power supply, we were keen to see whether these products could deliver both stable computer operation and a pleasantly quiet working environment.

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• Nexus KCZ-2700 (0 of 4)
• Testing the KCZ-2700 (0 of 4)
• Silent Power - the Nexus NX-3000 (0 of 4)
• Conclusions (0 of 4)