I have this server which does mostly file sharing (with the associated storage). No serious number crunching and it isn't the firewall. My current box has a Celeron D processor (Prescott 336 2.8 GHz); and I'm considering replacing it with a Pentium D (Smithfield 805 2.66 GHz) - for reasons which do not involve performance.

How can I know whether one can expect a higher or lower power consumptipn for the change? And how can I estimate the power consumption for each option?

  • Look at the specifications for each device which indicate its power requirements although your unlikely going to see any difference since they are from the basically the same product line. – Ramhound Aug 25 '14 at 15:17

The best place to start is to look at the TDP (Total dissipated power) rating for each CPU. This tells you how much power that each CPU will use when under full load.

Pulling from here and here:

  • Celeron D 336: 84W
  • Pentium D 805: 95W

So it would be reasonable to assume that on average, the 805 will use slightly more power; A marginal amount at low loads, up to 11% more at a full load.

The advantage with these two processors is that they are both around the same generation, so their motherboards and memory should draw about the same amount of power. If you're comparing different generations or classifications of components (DDR2 vs DDR3 memory, High-end gaming motherboard vs mini-ITX low-power motherboard, etc.) then I usually turn to eXtreme's Power Supply Calculator to get a feel for the difference between power draw at various processing loads.

The tricky part is the fact that the loads won't be the same: The Pentium D is dual-core, so for parallel tasks, it'll be using half the power. The Pentium D is also capable of SpeedStepping, which will reduce the power consumption by the CPU when it's not under a full load.

  • The Pentium D is also more powerful ( it being a dual-core ) and likely runs at a higher frequency. Even if its not "faster" its like more effective even if its slower – Ramhound Aug 25 '14 at 15:34
  • @Ramhound The Pentium D will also speed-step down to lower frequencies at low loads, so it may depend just on emperical testing. – Darth Android Aug 25 '14 at 15:39
  • Yes, it will indeed do that. – Ramhound Aug 25 '14 at 15:41

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.