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markw10 · Mar 17, 2007, 08:41 PM

I currently have a macbook pro but plan on getting a desktop mac sometime this year. My perfect computer would probably be the 'headless' mac but there's no such thing as that. I've even thought of a mac mini but I know power is limited. I ended up coming up with a Mac Pro. I don't like the idea of upgrading the iMac and then losing my monitor. I know there's a variety of processors I can use as well as other configurations. I'd likely add a 24 inch widescreen monitor to it but overall the Mac Pro does seem like overkill to me. If I get a iMac I'd likely get a medium range 20 inch model.
My question comes down to power usage (wattage, etc). It seems with the 4 core system out now and the future 8 core mac pro's that are rumored that this is a very powerful system and although nice way more power than I need. I like the tower case where I can expand it more than the iMac but with all those cores I can't help but wonder what type of power it uses. How does the power of a Mac Pro compare to a iMac? (wattage, etc) and are there many power saving features where the mac pro could use far less than maximum if I don't use full power? I see it is considered to be a energy star computer.

imitchellg5 · 01:14 PM

All Macs are Energy Star certified. The Mac Pro would certainly use more power than the iMac. But I don't think it would be a big enough difference to notice on your energy bill. For instance, when I got my Power Mac G4 which runs 24-7, our energy bill increased by only a few cents on top of the bill which has our iMac G5 on it. Remember that the Power Mac is much less effiecient than the Mac Pro even though it has only one processor.

Sub · 10:28 PM

How come? Just curious.

-Right, forgot, Intel is more efficient than IBM.

Big Mac · 12:35 AM

Originally Posted by imitchellg5

Remember that the Power Mac is much less effiecient that the Mac Pro even though it has only one processor.

Efficient? I'm pretty sure even a G4 DP 1.42 uses less power than any MacPro.

Lateralus · Mar 18, 2007, 10:28 AM

Originally Posted by imitchellg5

Remember that the Power Mac is much less effiecient that the Mac Pro even though it has only one processor.

Uh... What?

mfbernstein · Mar 18, 2007, 11:29 AM

Apple has the numbers for the Mini and Mac Pro, and Anandtech has some data for the iMac.

For the mini (1.83): min - 23W, max 110W
For the iMac (1.83 CD): min - 48W, max unknown
For the Mac Pro (2.66): min - 171W, max 250W

Of course the Mac Pro and Mini don't include a monitor in their calculations.

The Mac Pro is going to use considerably more power than either of the other two because, even at idle, because it's using 2 dual core desktop processors (Woodcrest Xeons) while the iMac and Mini are using 1 dual core laptop processor (Yonah or Merom).

Data from:
Mac mini: Power consumption and thermal output (BTU) information
AnandTech: Apple Makes the Switch: iMac G5 vs. iMac Core Duo
Mac Pro: Power consumption and thermal output (BTU) information

imitchellg5 · Mar 18, 2007, 01:13 PM

Originally Posted by Lateralus

Uh... What?

My Power Mac has one processor. Mac Pro has 4. Intel Xeons are much more efficient than any PowerPC processors. There is/was a chart to on Apple.com comparing G5s to Core Duos and Xeons too. Or were you refering to my bad grammar?

P · Mar 19, 2007, 06:46 AM

Note that you can reuse the iMac screen through a software hack:

Screenrecycler

Sub · Mar 19, 2007, 06:26 PM

imitchellg5 is right, in fact I remember whatt per clock cycle or something like that, or performance per whatt, was one of the reasons apple switched to intel, in the keynote they showed a bargraph. However, the insanely -large video cards and the 4 HDs probably adds a considerable amount of power to the needed amount.

Rick9876 · Mar 19, 2007, 11:30 PM

Actually, much of the idle power is used by the power supply. The Mac Pro has a large capacity power supply to be able to handle four hard drives, two optical drives, and four display cards. The best power supplies are only around 85% efficient.

Big Mac · Mar 20, 2007, 01:29 AM

Originally Posted by Sub

imitchellg5 is right, in fact I remember whatt per clock cycle or something like that, or performance per whatt, was one of the reasons apple switched to intel, in the keynote they showed a bargraph.

That's not what we're discussing her, Sub. Here the claim was made that the Mac Pro is more power efficient than the G4, which is false. The G4 was a low power chip. Those performance per watt comparisons had nothing to do with the G4.

Sub · Mar 20, 2007, 03:10 PM

Originally Posted by Big Mac

That's not what we're discussing her, Sub. Here the claim was made that the Mac Pro is more power efficient than the G4, which is false. The G4 was a low power chip. Those performance per watt comparisons had nothing to do with the G4.

Sorry, I don't memorize those keynotes, so I don't remember all the charts, it's cool if you do, though, that's why you're the PowerPc Zelot and I'm sub.

P · Mar 22, 2007, 08:15 AM

The G4 was a very efficient chip early on, around 400 MHz. When it got to 1.4 GHz, it wasn't very low power any more - hence the windtunnel Powermacs. The last Powermac G4s used 1.42 GHz G4s while the fastest Moto sold was 1.25. Apple overvolted and overclocked them to get to 1.42. That's rarely a way to get good performance per watt. Pair that with the fact that the performance of the G4 is far below a modern Xeon, and the performance per watt has to be much higher for a Xeon anyway.

Steve's graphs never compared a Xeon to a G4, no: it compared "future PowerPC processors" with "future Intel processors". The measurement unit was something he made up anyway, so what he really compared really doesn't matter.

mduell · Mar 22, 2007, 02:33 PM

Originally Posted by mfbernstein

Apple has the numbers for the Mini and Mac Pro, and Anandtech has some data for the iMac.

For the mini (1.83): min - 23W, max 110W
For the iMac (1.83 CD): min - 48W, max unknown
For the Mac Pro (2.66): min - 171W, max 250W

Those max figures seem a good bit low... 250W max for the Mac Pro can't be right.

How are y'all comparing "power efficiency" for a G4 and a Xeon? Just based on clockrate and number of cores? Or a specific application benchmark? Just for the CPU or for the whole system?

Leonard · Mar 22, 2007, 03:56 PM

I was going to argue that Power Consumption on a G4 had to be less than a Mac Pro, but I guess it's not true, Apple has this info for power consumption of Power Mac G4s:

Power Mac G4 power consumption and thermal output (BTU) information

Waragainstsleep · Mar 24, 2007, 02:43 PM

Not sure I follow entirely, but if you plan to buy a Mac Pro and a 24" display, and the Mac Pro is overkill, why not just buy a 24" iMac? If you don't think its upgradeable enough, just plan on retiring it for use as a TV. It should happily play back 1080p, so it will be fine as a TV set when you eventually replace it.

rehoot · Mar 29, 2007, 09:58 AM

Another consideration is that if you invest all your money in a Mac Pro, you might also want an uninterruptible power supply, which burns lots of electricity even if your computer is sleeping. I have a Mac Pro with a UPS, big monitor, extra internal hard drives, external hard drive for backups, and iSight. The totals system with all the extra junk burns a lot more electricity than the numbers for a bare Mac Pro. I unplug the extra things when I am not using them. I'm using my old G4 Power Book today. When I do video or audio or many things at once, it's time for the Mac Pro.

An iMac probably would have met my needs. I do like having RAID 1 redundancy on my main drive in my Mac Pro, and another RAID 0 for speed, but this is overkill.