2010 Mac Pro troubleshooting

[brentsg]

Hey all, could use some advice on some troubleshooting if anyone has suggestions.

I have a previously bulletproof 2010 Mac Pro running 10.11.4. It's been modified a bit:
-Hex core CPU upgrade
-The usual RAM upgrades
-Boot drive is Sandisk Extreme Pro on PCI card (Velocity Solo X2)
-Inateck 4 port USB3 PCIE card
-EVGA GF 680 card, flashed to Mac BIOS (same physical card as their Mac version)
-802.11AC Wi-Fi and Bluetooth 4.0 upgrades (from MacVidCards)
-Internal Blu-ray and HD-DVD drive in second optical bay

All of these upgrades have been in place for years with no issues. Suddenly the system will beachball and hang there, with a hard power cycle as the only recourse. Sometimes it remains stable for hours, sometimes minutes. This behavior started on Friday and it's seemingly random. There isn't any consistent pattern regarding usage that triggers this. Sometimes after the beachball begins, an app or two will close on its own as things hang.

I tracked down my old install disks and ran AHT over the weekend. It passes normal and advanced tests with flying colors. Temps look fine, fans are working normally. There isn't anything suspicious in the console logs.

Any thoughts? I'm fine with throwing a few dollars into a repair since it's my work machine and I don't see anything on the horizon that I'd want to replace it with. I just don't know where to start.

Edit: Extra symptom that might or might not be related. For several months, there would be occasions where the system wouldn't recognize USB devices that were newly plugged in. I'd have to plug/un-plug them a couple times on occasion and then it would be fine.

 

[fenderbass146]

HDD/SSD?. SMC/PRAM? I haven't had to much experience with Mac Desktops I personally would do a clean install to verify it's not a software issue. If the issues continues I would start by removing parts that you can and see if the issue continues to happen. You could also run some other hardware diagnostics. I personally use one for Eurosoft on Macs and PC's that has been pretty reliable.

 

[h9826790]

May be 10.11.4 is the issue.

If you have a backup boot drive with older OSX, try that.

Otherwise, you better get another HDD / SSD, make a clean install to check if the problem goes away.

 

[ActionableMango]

I agree with the others. If you have a spare drive, install OS X clean on it and see if the problems persist. If they do, you've a hardware problem. If not, software problem.

Did you check the log? Might be a clue there.

I'd also run memtest86 from a boot disk to thoroughly check all of your RAM. From a boot disk, not from within OS X.

 

[brentsg]

I'm giving things a go on the built-in NV driver, just in case there's something bothersome in the latest NV web driver first. I appreciate the suggestions and wish I hadn't just used my spare 1TB SSD to repair my sister's old iMac. I'll have to scrounge something up to swap the boot drive and give that a go.

Did check the logs and even watched them display nothing while it froze up. Also checked memory with the advanced AHT too.

 

[ActionableMango]

Also checked memory with the advanced AHT too.

People have had their memory pass AHT but fail in Memtest. I do not trust AHT for memory.