Wildly unpredictable performance issues!
I purchased an early 2008 dual quad-core 2.8 Ghz Mac Pro 3,1 for the almost-too-good-to-be-true price of $400 from eBay.
When it arrived, it was lacking a video card, the feet were badly bent and I found that the RAM was mostly non-functional.
I have made my peace with the leaning tower, installed 16 gigs of RAM brand new and because money is tight, I installed an NVIDIA GT 520 video card with 1024 MB of memory. I have no boot-up screen but once the Mac gets to the sign-in screen, all is good.
For the first 5 months after the Mac Pro was a champ! But in the last month, I've noticed that one of the front USB ports suddenly quit working. Internal hard drives will be randomly ejected without warning. I had a terrible scare when one of them ejected unexpectedly and wouldn't show up again even after moving the sled from one slot to another and restarting the Mac numerous times, but it lately just popped back up of its own volition.
I've ran SMART tests on all the hard drives and they're fine according to different tests. I've gotten a copy of the Apple's Hardware Test but my Mac Pro flat-out refuses to boot from the disc I burned so I'm stumped as to how I can narrow down the gremlin that is troubling my machine. I have a sinking suspicion that it might be the logic board although I've noticed some peculiar video artifacts when I visit websites that demand Web GL so that would tend to make me suspicious of the non-EFI video card too.
I have a buddy that has an identical Mac Pro but he has rebuffed my requests to borrow his video card so I could have a stock set up temporarily to attempt testing it again.
At this point, I'm at a loss as to my next step: should I just chuck this machine into the recycling bin and hope to score another Mac Pro with similar horsepower or maybe settle for an iMac from around 2009 or 2010?
I use my Mac to edit a lot of video (both SD and HD) and also a far bit of photogrammetry. I'm on a very tight budget these days and the most I could really afford to spend would be in the neighborhood of about $900.
The prices for a replacement logic board and/or video card are eye-wateringly high for a machine of this vintage.
Does anyone have any advice or ideas? I'm a Mac enthusiast at best so I don't know as much as many others here.