Welcome to the MacNN Forums.

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

You are here: MacNN Forums > Hardware - Troubleshooting and Discussion > Mac Desktops > Max Power use for 2008 MacPro

Max Power use for 2008 MacPro
Thread Tools
CIA
Mac Elite
Join Date: Dec 1999
Location: Utah
Status: Offline
Reply With Quote
Apr 24, 2013, 04:40 PM
 
Have a 3.2GHz 8 core MacPro 2008, 16GB Ram, with a 5870 in it, also have the original 8800GT with a Molex to 6 pin adaptor. If I run both cards, 4 hard drives, a PCIe eSATA card, and two superdrives, will it fry the PSU? (Assuming everything, CPU, both GPU, etc is running at 100%?) I can split the power off the Optical bay and snake it down into the PCI area to power the older 8800.
Work: 2008 8x3.2 MacPro, 8800GT, 16GB ram, zillions of HDs. (video editing)
Home: 2008 24" 2.8 iMac, 2TB Int, 4GB ram.
Road: 2009 13" 2.26 Macbook Pro, 8GB ram & 640GB WD blue internal
Retired to BOINC only: My trusty never-gonna-die 12" iBook G4 1.25
     
Administrator
Join Date: Jun 2000
Location: California
Status: Offline
Reply With Quote
Apr 24, 2013, 07:26 PM
 
Man, the CIA is supposed to know everything. I was reading the post, it was looking good - does look like a maxed out config. But you left out the amp reading.

You can assume 80-90% efficiency for a modern power supply. And the specs say 318 W (MacTracker) which is an output spec. So max input draw will be just under 400W.

Give us a reading. What's that puppy drawing?
     
P
Moderator
Join Date: Apr 2000
Location: Gothenburg, Sweden
Status: Offline
Reply With Quote
Apr 25, 2013, 03:28 AM
 
Well, the PSU shouldn't fry - generally they just make the entire computer start behaving weirdly when loaded, because it can no longer maintain power on the 12V rail. I wouldn't trust a reading at the wal either, unless you can somehow guarantee that you're loading both CPU and GPU to the max when testing - something that is harder than you think. Check the power supply rating of your Mac, and then type "power supply calculator" into google and pick one - I like this one. Enter your gear and see what it says, then compare to what your PSU says.

If you're going to really do this right and be certain, you have to calculate the load on each rail (=at each voltage). The problem is that most power-hungry things these days use the 12V rail, so that's the one you need to worry about. If you can find the rating on the 12V rail (there is often more than one, and the ratings are often printed on the PSU case), you can start adding up the amps for the power-hungry things like GPUs and CPUs to see how close to the ceiling you get on just that.
The new Mac Pro has up to 30 MB of cache inside the processor itself. That's more than the HD in my first Mac. Somehow I'm still running out of space.
     
cgc
Professional Poster
Join Date: Mar 2003
Location: Down by the river
Status: Offline
Reply With Quote
Apr 25, 2013, 07:35 AM
 
Don't all MacPros have a 1KW PSU? I know my model does (1,1 2006). 1KW is plenty for your use but run a calculator as suggested to make sure.
"Like a midget at a urinal, I was going to have to stay on my toes." Frank Drebin, Naked Gun 33 1/3: The Final Insult
     
Addicted to MacNN
Join Date: Mar 2004
Location: UK
Status: Online
Reply With Quote
Apr 25, 2013, 03:42 PM
 
Google says the PSU from the 2008 Mac Pro is rated at 980W.

If you allowed 100W for the four drives and 250W each for the GPUs (all overestimates), that still leaves you nearly 500W for the CPUs, the rest of the logic board and the eSATA card. Sounds like plenty to me.
I have plenty of more important things to do, if only I could bring myself to do them....
     
Mac Elite
Join Date: Jun 2000
Location: If I tellz ya, then I gotsta killz ya !
Status: Offline
Reply With Quote
Apr 27, 2013, 10:32 AM
 
Not being sarcastic, but do you REALLY believe that you are the only person out there that has loaded up & maxed out their machines........

And these machines have been out for how long now ?

What about all those graphic designers and music producers and scientists that use at least as many, and probably more, devices than you are........if a large number of their psu's were frying out under those loads, we would have heard about it by now

Seriously, just stop worrying, be happy & move on with your life
Personally I find it hilarious that you have the hots for my gramma. Especially seeins how she is 3x your age, and makes your Brittney-Spears-wannabe 30-something wife look like a rag doll who went thru WWIII with a burning stick of dynamite up her a** :)
     
Administrator
Join Date: Jun 2000
Location: California
Status: Offline
Reply With Quote
Apr 27, 2013, 07:08 PM
 
My MacTracker spec of 318W must have been typical usage. According to Apple's spec page for the 2008 MacPro, it has a maximum draw of 1200 VA. That strongly suggests a 1000W power supply.

It's designed for 4 HDs, 2 opticals, and at least one high-powered GPU + 3 regular cards. Plus a healthy safety margin. I'd say you're fine with whatever you want to throw in.
     
Addicted to MacNN
Join Date: Mar 2004
Location: UK
Status: Online
Reply With Quote
Apr 27, 2013, 07:24 PM
 
Yeah, just give it a go and don't sweat it. People take a lot of issues with Apple for a variety of reasons but those Mac Pros are seriously well built in every respect.
I have plenty of more important things to do, if only I could bring myself to do them....
     
   
Thread Tools
Forum Links
Forum Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On
Top
Privacy Policy
All times are GMT -4. The time now is 05:30 PM.
All contents of these forums © 1995-2014 MacNN. All rights reserved.
Branding + Design: www.gesamtbild.com
vBulletin v.3.8.8 © 2000-2014, Jelsoft Enterprises Ltd., Content Relevant URLs by vBSEO 3.3.2