Mac Pro 3.1 slow down issue.

2 replies [Last post]
Joined: Dec 20 2003
Posts: 72

Hi Guys, I run into this wierd issue.

Bought a used Mac Pro 3.1 a while back. it's a 2 X 2.8 model with a HD2600XT and 1GB RAM. First thing I did was more RAM. I got 12 GB in pairs in there now. I did a fresh install of 10.10. I notice the computer will lag a bit every once in a while as if if got hang up on a disk access or something. I was hoping 10.11 would help...Guess I was wrong. I also upgraded the video to 5870 hoping that would help. It didn't help much.

I was kind of living with it. It's only doing that every once or twice in a hour. Then it started to get worst in the last 6 months to once every 5-10 min. Started running activity monitor. The CPU load is always from less then 1% to about 27%. Memory used is only about 3GB out of 12GB. Not much Disk activities or Network activities. The system should be running very smoothly with these loads.

In the last 3 weeks or so, it got worst again. Every characters I type it freeze with a beachball for a few seconds. Reboot helped. But it would start doing that again in a few hours.

My Mac pro 1.1 with 2 X 2.66(4 cores) running 10.11 is smoother then the 3.1 with 8 cores. I got another Mac Pro 3.1 with 10.11 as well(I still like 10.10 better). It's running fine.

I swapped the RAMS between the two Mac Pro 3.1 already. So it's not the RAM or the riser card.

The computer is sitting in an unheated garage right now at -4C so I don't think it's temperature. I have also blown all the heatsinks and fans clean with a spray can.

Any idea or guesses on what's wrong? I am thinking of pulling the heatsink apart next and put fresh thermo-paste on them.

Thanks for any suggestion in advance.

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Joined: Dec 20 2008
Posts: 227
Re: Mac Pro 3.1 slow down issue.

I would guess a bad drive (maybe not even a drive that is being used, but it hanging the bus) or drive cable.


Peter Rittwage
Apple II/II+ Registry - Register yours today!

Joined: Dec 20 2003
Posts: 72
Re: Mac Pro 3.1 slow down issue.

It's a Mac pro. There's no drive cable.

I have 2 drives, Drive 2 is 3GB, contain all the data and constantly backed up and swapped between 4 drives.

Drive one had been backed up and swapped/rotated a few times as well. I can swap both drives with the other Mac Pro 3.1 and the problem stay with this one. I even run without the optical drive a one point to see if that changes any thing. Still the same.

The only thing remain unchanged are the mainboard and CPUs, PS and Case. I doubt the PS and case would be a problem. So it remain the board and CPUs.

Would an IDE cable without optical drive attached still cause problem?