PC fails to POST after 2-3 reboots unless CMOS is cleared

[Col. Buggernuts]

So for the past couple of weeks, my computer has POSTed slower and slower until it eventually stopped doing it at all unless I hit the CMOS reset button and go through the whole process of setting up the BIOS settings again.
Took the computer entirely apart, cleaned dust, connected components one at a time to verify they work (all the while hitting the reset CMOS button every 2 or 3 reboots), and so far the only consistent thing that makes the bloody thing POST properly is hitting the CMOS reset every two or three reboots.
Apparently the memory is a rather crap (and old) make, but as mentioned before there was no single or combination of RAM sticks that would allow the computer to POST properly unless the reset was done.

This PC has been in my possession for at least 6 years mostly as-is (graphics card is the newest bit, SSD a distant second), and the case, motherboard, CPU and RAM were in someone else's use before that to begin with.

Specs are as follows:
Intel Core i7 Extreme 965
EVGA x58 SLI Classified (141-BL-E759)
6 x OCZ Gold Memory Module 2 GB/1600 MHz 240 Pin DDR3 (OCZ3G1600LV2G) (12GB RAM total)
Gigabyte GTX 1050 Ti 4GB (10DE-1C82) (PCI-E slot 3)
ASUS Xonar DGX (PCI-E slot 2)
Crucial MX100 SSD 512GB (CT512MX100SSD1) (SATA 0)
2 x WD Green 500GB HDD (honestly completely forgotten the specific make) in RAID 0 w/ JMB363 controller on SATA 8 and 9
ASUS DRW-24B5ST DVD drive (SATA 1)
Windows 10 Pro (and up-to-date, probably)

Leaving BIOS settings as default, and configuring them to e.g. set the JMB36x controllers to RAID mode and regular ports to AHCI, have both resulted in the same issue. BIOS itself has been flashed to the latest version from EVGA's site (many many years ago).
I suspect it's just the motherboard on its way out, but on the insanely remote chance there might be a solution to this issue, I am thus posting it here.

[chunkymonkey]

Seems like a clear cut motherboard issue to me and given the age it's due for an upgrade anyway imo. That memory is really slow too.

Honestly you're probably lookin at replacing the CPU too if you get a new mobo since your current one is I believe socket 1366 which is no longer produced iirc.

Just my opinion but I'd just cut my loses and replace the mobo, CPU, and RAM. Of course that all depends on your budget.

[Col. Buggernuts]

Yeah, when (or if) I get enough money, the CPU, mobo and RAM are getting completely replaced. For now i'll be keeping it on terminal life support by hitting that CMOS reset.

[chunkymonkey]

Of course you never have to worry about slow post speeds if you never reboot or turn off your PC :v.

[Col. Buggernuts]

True :v
It would be a rather ignoble death for this veteran machine if it turns out to be a Windows update restart that kills it for good.