Windows clock continually loses time while my PC's switched on

[GfB]

I have a baffling problem with my Windows 10 PC. It continually "loses time" - the Windows clock is slow! It loses several minutes per hour.

Every time I sync it with the time servers, the clock jumps forward a bit. The problem only started in the last few days.
I've done some googling for the most likely causes but I'm still stuck...

1. CMOS battery - I could understand my PC losing time *while powered down* due to a dead battery, but would I really lose time *while it's running*? Doesn't the clock run on mains power during use? Further, wouldn't one expect other problems if my CMOS battery was playing up (like losing my BIOS settings)?

2. Malware - this seems exceptionally unlikely, as it's a relatively new fresh installation of Windows 10 with just my essential applications and utilities installed, plus I have run a full scan using Malwarebytes Anti-Malware which found nothing bad.

One final thought - this might be a stupid idea but...

Overclock settings - the one thing I've changed recently is I slightly lowered the 'vcore' voltage setting on my CPU. I could be clutching at straws here, but can this affect a PC's ability to keep the correct time?

(FWIW I'm very rarely doing anything strenuous to my PC. CPU load is usually low.)

 

[GfB]

Wanted to say a belated 'thanks' for the replies.

It looks like the clock problem was probably caused by the overclock/'vcore' setting.

Because that was the last thing I had changed before the Windows clock started playing up, I opted to reduce the overclock one notch and up the voltage slightly.

My PC's clock has been 100% fine since then.

By the way, my motherboard is a Gigabyte X58-USB3.

Thanks all!