new macpro furnace

[decay]

if he reduces the brightness on the display, does it get any cooler?

[M A V I C]

Tough to tell on the display. First thing I'd do is look up the specs. But as someone else mentioned, they may have just made the venting better in the newer ones. I know the older ones had color issues that may have been caused by heat.

[ADent]

Change the MacPro out for a mini or MacBook would save some heat.

[JoeH]

M A V I C wrote:
Tough to tell on the display. First thing I'd do is look up the specs. But as someone else mentioned, they may have just made the venting better in the newer ones. I know the older ones had color issues that may have been caused by heat.

Hard to tell from the specs posted on Apple's site on the 30" display. The current maximum power used is listed as 150 W for the current selling ones, and is the same as listed for the 30" model dating back to its introduction in 2004. Does he have the brightness set to the same level as his older one? With the CFL's cranked up to max, they will put out more heat. Or it may just be vented better as M A V I C thinks.

As for the Mac Pro itself, its heat output can easily match or exceed that of a G5, depends entirely on its configuration. The maximum current draw listed for a Mac Pro 8-core is 12 A at 115 V, which exceeds that of the last generation G5 with a maximum draw of 10 A. Main difference is that the newer machine has twice as many processing cores and still has greater capacity for drives and higher power usage video cards.

[M A V I C]

JoeH wrote:
As for the Mac Pro itself, its heat output can easily match or exceed that of a G5, depends entirely on its configuration. The maximum current draw listed for a Mac Pro 8-core is 12 A at 115 V, which exceeds that of the last generation G5 with a maximum draw of 10 A. Main difference is that the newer machine has twice as many processing cores and still has greater capacity for drives and higher power usage video cards.

Power numbers
Mac Pro (Early 2008) - 8 core: 318W max
Power Mac G5 Dual 2 GHz: 604W max

It's not just about energy draw, it's about heat output.
Mac Pro (Early 2008) - 8 core - min: 528 BTU/h max: 1085 BTU/h
Power Mac G5 Dual 2 GHz - min: 410 BTU/h max: 2060 BTU/h

I picked the two machines out of the group that use the most power. The dual dual core G5 actually was a little lower. The G5s run hotter in almost all circumstances, that's why some of them had to be liquid cooled.

The main difference is that the G5's run about 65°C at idle, and the Xeons run about 30° at idle.

[JoeH]

M A V I C, with computers heat output is closely coupled with current draw, about the only thing I know that is more efficient at converting electricity to heat is resistance wire. However, you are correct that the idle heat output will be much less with the Mac Pro. Everything else is going to depend on how many and which options are installed. Up to 4 drives supported vs. 2 and the higher end video cards and much more power to the PCI Express slots is available. What were your machines configured with? Well, looking at Apple's site and the document you would have gotten them from, you are comparing fairly minimum configurations, not as I said what they are capable of requiring.

As it is, the configuration of the Mac Pro you site is so minimal to be atypical of any in normal use these days:

Apple document wrote:
Mac Pro (Early 2008)
8-core 2.8GHz Configuration: Two 2.8 GHz Quad-Core Intel Xeon 5400 series processors, 12 MB L2 cache per processor, 1600 MHz dual independent frontside buses, 2 GB memory (800 MHz DDR2 fully buffered DIMM ECC), ATI Radeon HD 2600 XT graphics with 256 MB of GDDR3 memory, 320 GB Serial ATA 3 Gb/s 7200-rpm hard drive, 16x double-layer SuperDrive

More RAM, better video card and more drives will all increase the output well past that "max: 1085 BTU/hr" you quoted.

P.S. I was comparing the following:

Mac Pro (Early 2009) 8-core: Current: Maximum of 12A (low-voltage range)

PowerMac G5 (Late 2005) Quad 2.5: Maximum current: At least 10A (low-voltage range)

[M A V I C]

JoeH wrote:
M A V I C, with computers heat output is closely coupled with current draw, about the only thing I know that is more efficient at converting electricity to heat is resistance wire.

It's only closely coupled when the two computers being compared are of similar efficiency. Two G5 processors are capable of pumping out more heat than a dual quad xeon, loaded with RAM, a couple drives and a modern video card. As I mentioned, a Xeon is going to idle about 30° and a G5 around 65° (depending on the model.) That's a difference of about 95°F just in the processors.

That is by far the biggest heat producer out of all of the components.

What were your machines configured with? Well, looking at Apple's site and the document you would have gotten them from, you are comparing fairly minimum configurations, not as I said what they are capable of requiring.

As it is, the configuration of the Mac Pro you site is so minimal to be atypical of any in normal use these days:

Same with the G5. It was minimally configured as well. RAM doesn't really put out much heat, and a drive is going to output as much heat in a Mac Pro as G5. The G5 I cited had 160GB drive, yet you note the Mac Pro has a 320GB.

A baseline comparison between the two is only logical. If you're going to add on a bunch of hardware to the Mac Pro, you need to do the same for the G5. Comparing a loaded Mac Pro to a basic G5 makes no sense.

More RAM, better video card and more drives will all increase the output well past that "max: 1085 BTU/hr" you quoted.

Same is true, if not more true, for a G5. The one I cited was tested with only 512MB of RAM. Upgrade the video card, add more RAM, more drives... in the G5 and it is going to pump out a lot more heat as well.

But, again, it all boils down to the G5 being far less efficient than the Xeon. Even with the Mac Pro having more RAM, larger HD, faster video card... it still puts out almost half the heat as the G5.

[M A V I C]

I should also note that the G5 2.7 idling at ~65° is liquid cooled, vs the Xeon at 30° being air cooled.

I re-read your post and noted that you mentioned the Mac Pro can take 4 drives. Yes, two extra drives can output more heat, but it's still only a fraction of what the G5 processor creates.

[JoeH]

You still do not get it, for every 100 W of power going into a computer, about 100 W is going to come out as heat. That is HEAT not the CPU TEMPERATURE, it does not matter whether it is shedding that total amount of heat off a CPU surface at 65 C or at 40 C. But, then you are not the first person to confuse the concepts of temperature and heat. And you better rethink your "RAM doesn't really put out much heat", if you are going to be figuring out cooling requirements for a machine. Typical is around at least 10-12 W when active per 2 GB DIMM of the kind used in the Mac Pro's, less for the type of RAM used in G5's. So 8x2 GB DIMM's compared to 2x1 GB modules would be around 80 W more right there, or as much as an additional CPU. Power dissipation is somewhat higher for 4 GB DIMM's.

As for the drives, as they have gotten bigger, the next generation tends to use the same power as the previous one, so the 160 in the G5 would have been comparable to the power usage of the 320 in the Mac Pro. But, while at it, add about another 10-15 W per active drive, and that is using a "normal" pattern of 40% random seeks, 40% read/writes and 20% idle. Mac Pro can have up to 4 drives and be a supported configuration, while the G5 only 2 drives.

The final big difference is going to be in that PCI Express bus, where the Mac Pro allows up to 300 W usage, and for the higher power video cards supplements that with a direct connection to the power supply. The G5 max'd at 150 W for the video card.

So your contention of:

"A baseline comparison between the two is only logical. If you're going to add on a bunch of hardware to the Mac Pro, you need to do the same for the G5. Comparing a loaded Mac Pro to a basic G5 makes no sense."

One, it does not address my contention that max'd out a Mac Pro can meet or exceed the power requirements and heat output of a G5, and Two, ignores that you can add less to the G5 before the system runs out of space and power.

As for your choice of G5, I picked the late 2005 model because it uses even more power than your example and comes closer to the Mac Pro's max.

Quad 2.5 GHz Power Mac G5 (Late 2005)

Two dual-core 2.5GHz PowerPC G5,1.25 GHz frontside bus/processor, 1MB L2 cache/core, 512MB of 533MHz DDR2 SDRAM (PC2-4200), 250GB Serial ATA drive, 16x SuperDrive with double-layer support (DVD+R DL/DVDRW/CD-RW), 3 PCI Express slots, NVIDIA GeForce 6600 LE with 256MB of GDDR SDRAM

Power Consumption: Idle/CPU Max 185 W / 550 W
Thermal Output: Idle/CPU Max 631 BTU/h / 1877 BTU/h

They do include a note on that page that just the fans speeding up to handle a higher room ambient temperature will raise the max power by 50 W, or to over 2000 BTU/h.

[M A V I C]

As you noted, the Late 2005 quad mac pro outputs less heat than the G5 I was citing, yet it uses more power. That similar to what I'm saying about the Xeon - just be cause it's "rated" at more power, doesn't mean it outputs more heat. And in the test, even if adding more RAM, video card... to the Mac Pro, it still has to almost double its default BTU output to match the G5.

You still do not get it, for every 100 W of power going into a computer, about 100 W is going to come out as heat. That is HEAT not the CPU TEMPERATURE, it does not matter whether it is shedding that total amount of heat off a CPU surface at 65 C or at 40 C. But, then you are not the first person to confuse the concepts of temperature and heat.

You're still making an inaccurate comparison. The Xeon uses far fewer watts than the G5, so it's going to output less heat than the G5. That is by far the biggest difference between the two.

And you can't use theoreticals here. You have to take into account things like the old power supplies being much less efficient. There's power loss all along the way. The greater power loss, the greater the heat output. All that energy doesn't come out as heat, it comes out as other forms of energy too.

The Mac Pro is a far more efficient machine. Again, hence why Apple had to add liquid cooling to the G5, but not the Xeon. The G5 produces more heat.

The TDP of the Xeon is about 130W. It's tough to find G5 numbers, but the best I could come up with was that a single G5 2.5 CPU used 125W. Since they came in dual configs, that's 250W. The 2.7GHz obviously used more.

And you better rethink your "RAM doesn't really put out much heat", if you are going to be figuring out cooling requirements for a machine. Typical is around at least 10-12 W when active per 2 GB DIMM of the kind used in the Mac Pro's, less for the type of RAM used in G5's.

Compared to the 250W+ of a a pair of G5 processors, I still think 10-12W of a pair of DIMMs is not much. You'd have to have 10 pairs in a Mac pro to equal the heat difference between a G5 and a current Xeon.

Not only that, but I think people were more apt to put more, smaller RAM chips in a G5 than in a Mac Pro.

The final big difference is going to be in that PCI Express bus, where the Mac Pro allows up to 300 W usage, and for the higher power video cards supplements that with a direct connection to the power supply. The G5 max'd at 150 W for the video card.

Yes, I agree, if he put a huge power hungry video card in that does have potential to create a fair amount of heat. Still not as much extra heat as the processors, but a fair amount. The most powerful video card Apple offers uses up to 236W. For the G5, it was about 123W. So a 100W+ difference - still less than the difference between the G5 power usage and the Xeon.

One, it does not address my contention that max'd out a Mac Pro can meet or exceed the power requirements and heat output of a G5, and Two, ignores that you can add less to the G5 before the system runs out of space and power.

I still don't think it would be easy to do that.

As you look at the specs and see the comparatively, low power usage of things like the video card, ask yourself how the G5 would still use so much power and through a process of elimination, you can see it's the processors.

On a side note, I have a nehalem machine here, GTS240, 4GB RAM... and it puts out far less heat than the G5 2.7, 9650, 4.5GB RAM... I just sold.