CPU Fan Dimension 8400 Wiring

So leaving off the blue wire will make the fan run at one speed?

I actually upgraded from a 8200 to 8300 and pulled the fan out of the 8200 and used it in the 8300 for neally 3 years without any problems but mine you the 8300 had a P4 3.4Ghz Northwood cpu in it, I knoe these 660 cpu's are Prescotts and run alot hotter

Red is 12V, black is ground, white is tach, blue is PWM speed command.  On a 3.6GHz CPU, it is inadvisable to replace the fan with one that has no speed command.

 

If you want the system to work right and last, get the right fan.  If that doesn't matter, leave off the blue wire.

Dimensions evolved from single-speed fans in the <1GHz days, to tach fans (3-wire, unregulated) to exhaust-temp-sensing fans (tach plus thermistor, like in 2400 but not since) to tach plus PWM speed control based on the CPU die temperature.

 

If you put a thermistor fan in a system designed for die-temp monitoring, the fan can still react to CPU load changes but with much more hysteresis--that is, delay between when the thermal load takes place and when the fan responds.  If you put a single-speed (tach only) fan in a system designed for die-temp monitoring it will almost assuredly be inadequate unless the ambient is <75F.

 

If nothing else, fans are cheap and Pentiums are expensive.

Thanks for that info, been looking for it for months.

So, could you recommend a 4 wire 90mm quiet fan suitable for the Dimension 8400 with a 660, 3.6GHz CPU?

 

Cheers

 

Dell CPU fans are catalog items from Datech and NMB.  Just buy the features--tach, PWM, ball bearing--and you have a Dell fan.  Match the watt rating (it's on the label) and you match the max CFM.  There's still the matter of connector size that matches.  But there are so many Dells out there that aftermarket parts vendors often identify products by the Dell model they go in.  Shouldn't be too hard to research.  So you have a point of reference, lookup Dell's price on the fan--some are under $10 US--scarcely worth worrying whether the plug will fit unless you find a MUCH better price.

 

Sorry, I don't have a model # or preferred vendor to suggest.