Hi, hope someone can help with this one! Very exhausted with trying various options already, and it's coming down to either a bad CPU or motherboard.
Motherboard: Gigabyte Z87X-D3H (tried bios F8 and F9)
Onboard graphics (HDMI)
CPU: i7 4790k
RAM: Kingston 4GB (tried all of 4x 4GB sticks I intend to eventually use in this machine)
PSU: Corsair RM650
Cooler: Noctua NH-U9S
While it very occasionally boots up fine (usually a cold boot), basically the machine usually keeps rebooting before POST.
If I leave it on its reboot cycle, it will eventually go into POST after 50 or so attempts, and I can enter UEFI bios after it does not find a boot device (I haven't got one connected yet). The CPU is detected fine in the BIOS when I get into it.
I updated the bios on this board using a G1820 CPU (so that Haswell Refresh would be recognised), and the machine boots into POST and BIOS every time when I swap the i7 for the G1820.
I also swapped out a known working PSU (Be quiet L7 630w if I recall correctly) and the same behaviour occurs, so I'm pretty sure the PSU is fine.
So I guess I'm asking - is this likely to be:
- a faulty CPU?
- is this even possible if it works *sometimes*?
- or a faulty motherboard?