Computer system power usage

The actual current drawn will depend significantly on processor numbers and loading, the amount of memory fitted(and hence page swapping needed), etc. You can only calculate this very approximately - only by setting the thing up running and measuring with a true rms ammeter are you going to know the accurate figure.

However, I suspect that they will not bill you based on the actual power use but on Dell's "power configuration calculator" standard figures for this configuration. Which is 2.1Amps

You can go to Dell's web site and get their figures for standard configuration power loadings.

I have a PII 450mz machine that runs very happily on a 135W inverter with power left over for a fairly big speaker system. (no monitor) It is a MP3 player in my car.

That's only for resitive loads. The current drawn by a computer PSU will usually be higher than you would calculate this way, just how much higher depends on the quality of the PSU.

450W is going to be the max the PSU can deliver, and it will normally be running at less than this. I have an older 2 x 2.4GHz Dell at work with two SCSI disks. That idles at 200W, which increases to 300W with both CPU's running flat out and some load on the disks. I haven't measured the current draw, only the power consumption using a true power meter, but that would probably be at least 1A idling.

It doesn't look like the internet hosting provider you have chosen is suitable for that system.

I agree. The provider has very cheap rates, but average power consumption of over 1 A adds more costs than what I pay for hosting (rack space + traffic). That's why they were so cheap.

The Dell has a 3Ghz Xeon processor, 1 GB memory and 2 disks. There's 7 fans (which I can see) and the IPMI tool reports that there's a total of 9 fans on board. The provider gives an average of .5 A for free.

110W would be free. Anything above that is charged. I haven't measured anything (lack of tools), but I can imagine that this configuration draws more than 110W when idle. If I add a 2nd Xeon CPU, then the system will be drawing even more.

I remember back in the 386/486 days that some computer magazine tested CPU heat generation when idle for both DOS and linux systems. The DOS system kept executing (NULL) instructions when idle causing the CPU to reach a temp. of approx. 90 degrees Celsius, while the Linux system only reached 60 degrees when idle (on the same hardware). I expect that will be different for current day operating systems, but in this hosting situation it would make a significant difference in cost.

I'm glad I spotted this clause. I since then have contacted another provider with higher rates, but with no electricity charges. If I draw .7 A on average, then this new provider actually works out to be cheaper than the provider which charges for power usage.

Thanks,

Miyagi

That may well be correct. One interesting observation I made is that disabling one of the CPUs in the BIOS makes no difference to the system's idling power, although at max load (which is now just one CPU), consumption is only 250W. I haven't tried pulling a processor out to see what effect that has.

It probably wouldn't be different today. The other thing to watch is that whilst more advanced OS's will execute a HLT instruction in the idle loop to reduce power consumption, BIOS's often don't, and you can find that if the PC ends up in the BIOS with something like "Keyboard error press F1 to continue", the power consumption can be maxed out.

I think can now safely install a 2nd CPU:

I have since found another hosting provider which has a clause that they start charging from 1A average per month. Apparently they don't measure power consumption, but just check the equipment specifications. They allow you to hook up a powersupply with a maximum of 1200 W. Then they only start charging for electricity if your power supply is rated above 3800W.

It is an interesting topic as more and more hosting providers seem to have some kind of power consumption clause. Many providers have just started to specify power consumption clauses since January this year.

Thanks,

Miyagi

It may be that the increasing costs of energy are getting through. (incidently, I think maybe you mean 120W and 380W?)

Good to see! Unless, of course, you are worried about work and jobs flowing to those parts of the World that are energy-rich. A great many have already gone overseas because of the relative cost of wages and social provision. A great deal of manufacturing jobs have gone to those countries where raw materials, and labour, are cheap and plentiful.

The increasing effects of inequalities in energy prices could be yet another nail in the coffin...

I think can now safely install a 2nd CPU:

I have since found another hosting provider which has a clause that they start charging from 1A average per month. Apparently they don't measure power consumption, but just check the equipment specifications. They allow you to hook up a powersupply with a maximum of 1200 W. Then they only start charging for electricity if your power supply is rated above 3800W.

It is an interesting topic as more and more hosting providers seem to have some kind of power consumption clause. Many providers have just started to specify power consumption clauses since January this year.

Thanks,

Miyagi