Power Requirements and PSU size

[NinjaNurse]

My current (Ivy Bridge) PC has a 750W PSU in which is excess but that always left me comfortable.

My new (Coffee Lake) PC uses 140W and comes with a 350W PSU. I will be adding things to the PC. At very least two hard drives, a blu-ray drive and powered USB devices.

How can I find out how much power the PC is drawing and so if I need to upgrade the PSU?

 

[Oussebon]

A larger PSU would probably have been advisable especially for future GPU upgrades.

Your two easiest options would be to a) configure your specs in the PC Specialist configurator, add the extra things you want on top of that, and see whether it throws a warning about the PSU, or b) to use something like https://outervision.com/power-supply-calculator

Hard drives, optical drives, RAM, and basically anything that isn't a CPU or GPU tend not to use all that much power by themselves. So your 350W PSU may well be enough for minor upgrades.

I'd make a general comment that buying a PC and already planning upgrades to the extent that the PSU may need replacing is probably not best value versus getting a spec that caters more fully for those upgrades from the outset.