Sorry the PSU is a Seasonic S12II-520w, I've set the Low Power States c6/c7 in BIOS for a fully compliance with the CPU Haswell, but doesn't seems this the problem...
Thanks for joining the Desktop Board community.
I understand your computer does not power down when hitting shut down option, it restarts instead.
At this point, this may be an issue with grounding, it is recommended to take board out of the chassis and check if your computer will shut down.
The processor LED turns red when there is an overheating issue or processor is running hot.
Reseat processor and apply thermal paste. Check the link below for some tips regarding processor overheating:'
Try updating computer BIOS:
thanks for reply, exactly the problem is that, I have a restart instead a shut down. I've notice that if the PSU is OFF and then ON the first time the computer shut down normally, but with the cpu red led at the boot and at the shut down. After this first time goes in boot loop!
I've fallow the procedure for testing issues, the motherboard is out of the chassis and there are only one ssd connected. All is well fixed and the cpu heat is 37 degrees, BIOS is the latest. Probably the PSU have some problem with this motherboard, but with other works great.
Thanks again, I will do some test with other PSU
Thanks for the update, yes, it does sound like power supply issue.
The Haswell processor's power management capabilities were a vast improvement over that of previous generations. In fact, when the processor goes into its lowest power states, its power draw can be so low that many power supplies intended for previous generation systems see this as an error and shutdown. You need to ensure that the power supply you are using is certified for Haswell. There are multiple sources for such certification lists. The alternative is to disable the use of these lower power states (C6/C7). This can be done form the Power Settings scene in Visual BIOS. This causes your system to draw more power all the time, however...
definitely there's an issue with PSU, I've disabled the 'Power Supplies Supervisor' in BIOS and shut down works normally, remain the single blink of red Hot Cpu led while booting and stopping. I was excluding the power issue cause Seasonic usually is very accurate and stable, but mine is one year old, and I recognize there's a little problem with groundig or similar as Allan saw. Is possible that in new condition this PSU works well with Haswell too, but mine have something very small out of range. Anyway I'm waiting a new one...
Thanks again, finally found the problem!