Combined Watt large difference? TX650M-850

Hello everyone!

Upgrading to a 1660 TI and a TX650M PSU (or 750).

But now I'm concerned about the PSU Combine watts for the TX650M...

If you look here (TX series spec sheet)

https://www.corsair.com/corsairmedia/sys_master/productcontent/TXM_Manual.pdf

Or google - tx750m 612w

 

You will see the 750 & 850 combined watts on the 12v rail doesn't drop much...

744w and 849w

 

But for the 650 or 550, the combined watt drops to 612w and 516w

 

Can anyone please explain such a difference? I was going for the TX650, but now thinking about the 750 only for this difference. is this something to be concerned about? :sigh!:

 

Thanks, everyone!

:idea:Because it looks as tho this was designed as a 600 watt PSU, but since they got "above" average ratings, they're selling it as a 650 watt.

 

What are your thoughts?

Anyone? all input welcomed.

I can't explain efficiency differences without really diving into the PSU construction, but it stands to reason a less expensive, lower watt PSU is going to be less efficient than a higher watt model in the same family. However, rather than delve into the percentages, the real questions is if 600W is any way cutting it a bit close to what you think you need, then go a size up. There is nothing worse than getting stuck with a PSU that does not meet your needs and then have no use for it. The specified TDP for the 1660 is quite low, but I don't know if that reflects actual use or not. Nevertheless, I would not want to be running this class of PSU at 100% or really any other for that matter. If you are close, go up. Also, while stock seems to be limited, I am not seeing a real price difference between the TX650 and 750. That should make it an easy decision.