AMD's official line on max continuos running temperature is 70C for the XP, with a burn out ceiling of 95C.
But it is generally considered that 60C is the Max continuos for stability.
gargouille, over the years I have tried all sorts of fan configurations and I am afraid I would have to disagree with the two fans blowing in theory.
With this method you are going against natural heat convection not to mention general case design and thousands of research man hours.
exhausting at the rear top or back is a much more effective method.
I think hybrid needs to buy a better heatsink/fan combination as the case fans he has in place should be OK.
Typical STOCK fan rpm's are:
80mm fans: 2,300-2,800
70mm fans: 3,300-3,750
60mm fans: 4,700-5,100
of course there are high performance variants in all sizes:
High powered/CFM
60mm fans rpm: 6,800-7,200
80mm fans rpm: 4,600-4,900
The high powered fans such as the famed Delta series
are extremely noisey (be warned)
Exceptable noise levels (usually below 36db)
If you fan rpm figure is intermittant it is nearly always the fan itself that is the cause.
To keep the CPU noise to an exceptable level but still have a very effective cooler many manufactures are fitting bigger 80mm fans on there coolers, they turn slower , create less noise but have a similar CFM figure to a smaller noisier fan of the same air moving power.
54C is a bit warm if thats your idle temp but might be quite exceptable if you live in a warm climate.
This figure could easily be 6-8 degrees warmer under load which would take you into the 60's and approaching the limits of temperature stability.
Martin
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