I can't offer any substantive advice with respects to your 3,1, but perhaps the PSU might warrant some attention, if not now in the future. From what I read at the time I was trying to have it addressed (and when the issue was plaguing me the most), I had come to understand this issue to be endemic with other Mac Pros. My early 2019 Nehalem 4,1 Mac Pro has some issues with its PSU. OK, more soon, this will be checking off a bucket list item for me and hope that you’ll enjoy my enthusiasm as the build unfolds.
HOW TO OPEN MAC PRO POWER SUPPLY 2008 UPGRADE
It looks quite easy to upgrade the wireless chip though that’s expensive for what you get in return and I’ve got LAN nearby. It’ll be my new shop toy and will mostly serve as a terminal to login to the home NVR, view files, regular work communications, and of course to pump out optically perfect Toslink to the shop AV. What will the computer need to do? Not much, it’s a piece of jewelry.
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That’s mostly SSD theft, though I might try out the GTX 1060 from it and say an install of a High Sierra to leverage that GPU (still no sign of drivers from NVidia for Mojave and 10xx cards). Other plans: merge my shop computer’s guts with this. So dual boot in the end, and the early OS will require that I track down a working older GPU as the 680 requires 10.8 or later. To that end I’ve got a GTX680 on the way so that I’ll be able to run Mojave on it, though my stronger interest is in restoring a fully classic install of 10.6.8SL as that was my favorite Mac OS. Even the mainboard’s battery still has over 3V. Specs as I can tell are a single 2.8Ghz QC Xeon, aforementioned dead GPU and good RAM, the mainboard appears to be working perfectly, and we’ll see about the optical drives as I get it to boot. Power Supply checks out, fans all spin up, RAM riser LEDs all go blinkers blink at power on. The verdict is that the OEM 8800GT graphics card is shot, and that there are four good chunks of 1TB spinning rust in the sleds, and 4GB of DDR 667 EC-RAM. Tonight I had the energy to take apart the machine for testing. With it I obtained the original box and keyboard/mouse combo. It lived in a climate controlled environment since being deployed in ‘08 though the business was shuttered for three years. The MP that I’m working on is a pull from a small audio production business.
Gonna just drop this topic here for now while I’m waiting on parts to roll in as I’ve always wanted one of these machines but could never justify the expense.