Mac Pro 3.1 Early 2008 CPU Upgrade!

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Mac Pro 3.1 Early 2008 CPU Upgrade!

So i have a Mac Pro Early 2008 1 x Quad Core 2.8Ghz, 24Gb of ram, ATi Radeon XT2600 and a lot of hard drives!

Basically I decided it was a good idea to try and do a processor upgrade to two 3.2Ghz X5482 intel Xeon chips as the thing was being stretched whilst doing heavy processing (I do music production). I researched some forums and the detail around it and got some X5482 on eBay for £80, bargain! I then had to get a heatsink so reached for eBay again. I took everything out, swapped the processors over, used thermal paste on the CPU and put everything back together.

The startup first time:

Power fine
No chime
No LED on powerboard
No click to load the disks
Fans spin up ok
Graphics card fan spins at max
Drives spin up

I then tried taking everything out and starting one by one, 2Gb ram, add graphics card, no hard drives etc but still the same result, only leaving the computer running for 20 seconds max! I then tried putting the one Quad core 2.8Ghz back in but I still get the same result. The diagnosis LED's show the standby and EFI lit but nothing else, There is a flash on the OT A and OT B CPU LED's when the power is connected!

I believe i have fried my motherboard or PSU!!

I have the service manual and don't see these symptoms in this order there but they do say to similar symptoms to replace either the front power board, motherboard or PSU.

If anyone has any ideas or suffered similar problems please contribute your advice?! Looks like i might have to start again and see how much the sting of a new mac will be.

Many thanks

Mac Pro, OS X Yosemite (10.10.5), 3.1 Early 2008 1x2.8Ghz

Posted on Sep 28, 2015 3:02 PM

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Answer 1

lllaass

Level 10

210,513 points

Sep 28, 2015 3:15 PM in response to Originmusic

Does it work if you put old CPU back?

Otherwise I would get a used 2009-2012 Mac Pro and then upgrade as necessary.

Are you sure the original installation would be significantly improved by upgrading to two processors?

Did Activity monitor show 100% CPU?

Usually disk IO is limiting when you have enough memory.

You can install very fast PCle-based blade SSD card.SSD Blade Drive for "Classic" Mac Pro

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Answer 2

Sep 28, 2015 3:28 PM in response to Originmusic

No chime:

The LED to look at when all the stuff is removed and you power up, and the fans turn on, is the LED on the power button. If it is blinking, your Mac is alive, but does not have enough working RAM to start up.

You then need the chime before you can add anything more than RAM back in. There is no point in skipping ahead, there will be no chime until you have a Mac with enough working RAM to start up.

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Answer 3

Originmusic Author

Level 1

0 points

Sep 29, 2015 1:50 AM in response to Grant Bennet-Alder

HI Grant

yes you are absolutely right. There is however no chime or LED above the power button at all anymore, it doesn't come on at all! should I start off with nothing but the logic board and RAM? No processors, graphics card or drives?!

Many thanks

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Answer 4

Originmusic Author

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Sep 29, 2015 1:59 AM in response to lllaass

Thanks IIIaass.

No joy with the old CPU so far. Yep it looks like I'm going to have to start with a second hand newer model. I think it would of helped as it was maxing the processor out using ableton and logic but a safer option would be an ssd in hindsight, seemed worth the cost as opposed to buying a new machine.

Thanks

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Answer 5

Sep 29, 2015 8:32 AM in response to Originmusic

Make certain the 3Volt coin cell battery measures at least that amount in-hand. In circuit, you are actually measuring the "always-on" power supply, so it can fool you.

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