[Todd Madson]

All:

Has anyone found that running a G5 under heavy load produces scarcely believable
operating temperatures? I'm noddingly familiar with the PC overclocking scene and
ran into temps of 120-140 degrees under a cooled CPU but this dual G5 2.5 can
produce some temperatures when under load that is ..... scary.

The memory controller heatsink temperature tends to go the highest, I'm running the
app that keeps track of temps and it has been as high as 213 degrees farenheit which
is unearthly to me. The CPU temps range anywhere from 116 degrees idling to around
176 when under heavy load themselves.

Odder yet, I can feel a wave of warmth when near the unit and while I'm not running it
heavily 100% of the time I'm a bit concerned for its overall lifespan since doing audio
and video work is part of what I do as well as running the occasional distributed
computing app. When I ran X-Plane last night the fans revved up to full blast and
I though the thing was going to take off itself.

The machine seems just fine but temperatures over 200 degrees seems like a
recipe for trouble.

Mine is a dual 2.5 and it certainly is an eye opener. I know the dual 2.5 and 2.7
units were supposedly overclocked 2.3s with liquid cooling but....wow.

Any 2.5 or 2.7 owners using the temperature sensor app that keeps track of this and
getting similar readings? I ponder how accurate it is but the blast of heat coming out
of the rear of the unit is seriously frightening..

Any owners of duals want to comment on heat and power consumption? I'm dreading
the first electric bill I get the month after getting this thing.

[d.fine]

I don't have a DP 2.5 but a DP 2.0, and this machine has gone to 74°C / 165°F for both the CPU's and the Memory Controller Heatsink. I put a heavy load on it at times, so that both CPU's go at 98-100% all the time, and the temps stated are the maximum that have been reached. On average (like now) running Seti on the background while using Safari, Adium, iCal, Toast, Mail, iTunes, Hardware Monitor and so on and so forth, the CPU's are at 72° and 71°C / 161° and 159°F , the MCH is at 70°-72°C / 158°-161°F . This is a common scenario for me, I see these temps all the time.
Sometimes I feel a little heat comming from the machine if I put my head next to it. The temps you mention do seem a little over the top. How fast are the fans going when you reach those temps? Are they going full speed? Temps over 200°F which is 93°C are scary. Have you consulted about this at an Apple Store? Maybe thy know more.
I didn't notice any difference in my electric bill. Its not like it uses a KWh, I thought about this as well when I got my DP machine, but I haven't seen any change. Maybe it's just my use.
Good hunting.

[Todd Madson]

I'm going to be talking to one of the Apple Store folks since the app I'm using ("Temperature Monitor")
I can't be certain how accurate it is.

I set the CPU performance back to "Automatic" and it seems much more reasonable but I'm thinking I
could heat a small room in the winter with the high performance setting. With summer coming on, the
high performance Seti crunching might have to just wait until it cools down a bit or we go to central air.

As far as fans - they fluctuate - if it gets really hot in there you hear them rev up, they were not on
constant.

[d.fine]

The temps I posted are measured with Hardware Monitor, it is basically the same as Temp Mon you use, same maker, just more features and shareware. I don't think it's the app giving wrong temp data, because it is all based on OS X built in fan & temp monitor system. But you never know.

I've been thinking about stopping SETI for a while as well. Yesterday was very hot here (32°C) and the HD Bay fan was going full speed non-stop. Which had me worried a little. One HD read around 40°C but the std Hitacht HD has no temp sensor, so I don't know how hot it was running.

My fans now at 72° & 71°C are between 600 - 900 RPM for CPU0 and 300 - 380 RPM for CPU1. This is what I find very odd. When CPU0 reaches 72°C the fans go up to 800 - 900 RPM, but when CPU1 gets up to the same temp the fans only get to 400 - 450 RPM.

[Al G]

I run Folding@Home all the time as you can probably guess by my sig. My rev. B DP2.0 (with 970 processors) ran at a pretty constant 66.1C for both CPUs under full load. My DP2.3 runs at just over 74C! But the machine seems to be comfortable at this temperature because the CPU fans are only spinning at 800-1200RPM on a really hot day. There's plenty of RPM headroom; I think they max out at 3200RPM.