Running 32bit OS on 64bit CPU vs 32bit CPU

[Rouxenator]

Is there any gains you get from the additional registers present on a x64 CPU when you run a 32bit OS? Or do they simply remain unused?

The reason I ask is I am getting a low end VIA Eden X2 1Ghz computer (again) and it has 4GB or RAM. So I can go either 64bit or 32bit, leaning towards 32bit, but will it be better to run 64bit?

For one thing, I know I'll be able to run ancient 16bit programs on the 32bit OS - not possible on 64bit - but that is about all I can think of.

 

[Johnatan56]

Is there any gains you get from the additional registers present on a x64 CPU when you run a 32bit OS? Or do they simply remain unused?

The reason I ask is I am getting a low end VIA Eden X2 1Ghz computer (again) and it has 4GB or RAM. So I can go either 64bit or 32bit, leaning towards 32bit, but will it be better to run 64bit?

For one thing, I know I'll be able to run ancient 16bit programs on the 32bit OS - not possible on 64bit - but that is about all I can think of.

Well the OS should only give 32bit instructions to the CPU, so no performance enhancement.

Do you really need to run 16bit programs? For that one use case that will never happen you could rather just spin up a 32bit VM to run it on. But do you really need that?

EDIT:
Do note some software providers are dropping 32bit support. Chrome tries to auto migrate to 64bit if 4GB of RAM is installed and OS support, FF as well.

EDIT2:
http://valid.x86.fr/bench/nl2fax/2
lol, scroll to the bottom. I know, it's got a TDP of 9W and is 7 years old.

 

[Rouxenator]

Yeah, might as well go 64bit. I had one of these 2 years ago, HP T510, it was a bit slow. But since then VIA did release drivers for the GPU so I'm hoping the one I got this weekend will work better. Would be awesome to get my hands on a newer X4 Eden at 2Ghz, but those boards sell for more than my Ryzen build. Maybe they'll make their way into a thin client of sorts in the future.