Am I the only guy on the internet with this problem?

An ISO is simply an image file. In this case, the ISO files contain an image of the Windows installation files which will run when you burn the ISO to a disc and then reboot your system with it installed (assuming you have a disc set to run before the hard drive/SSD in the BIOS). You have one for Win 7 and the other is for Win 10 so there's not a performance issue. If you boot the Win 10 disc on your Win 7 system, it will try to install Win 10. You can choose to either overwrite Win 7 or install it on a different partition or drive connected to your system. The ISO files also contain a Startup Repair option which you can run. Obviously, if you don't want to install Win 10, you would use the Win 7 ISO.

In regards to the screen resolution, right click on the Desktop and select Personalize. I'm not on my Win 7 system right now but you would want to find Change Display Settings. You can set the screen resolution there. Sorry I can't give you the details at this moment.

wither 2 said:

An ISO is simply an image file. In this case, the ISO files contain an image of the Windows installation files which will run when you burn the ISO to a disc and then reboot your system with it installed (assuming you have a disc set to run before the hard drive/SSD in the BIOS). You have one for Win 7 and the other is for Win 10 so there's not a performance issue. If you boot the Win 10 disc on your Win 7 system, it will try to install Win 10. You can choose to either overwrite Win 7 or install it on a different partition or drive connected to your system. The ISO files also contain a Startup Repair option which you can run. Obviously, if you don't want to install Win 10, you would use the Win 7 ISO.

Thank you wither. This was clear to me obliviously.
I was not referring to the Startup Repair PE mode included in the live isos.
I was asking SIW2 which is faster between a FULL Win7pe OS and a FULL Win10pe OS (like the ones he posted).

wither 2 said:

In regards to the screen resolution, right click on the Desktop and select Personalize. I'm not on my Win 7 system right now but you would want to find Change Display Settings. You can set the screen resolution there. Sorry I can't give you the details at this moment.

The resolution came back to 1366x768 after I uninstalled the driver and rebooted.

SIW2 said:

It is better to use winpe that matches the installed OS. For example, windows system recovery options in winpe are intended for the matching OS.

Sure

SIW2 said:

Faster at what? And why?

I was asking a different question. I have 2 old PC with very slow mechanical hdds (2.5 ide and even worse) My idea was to install a live Windows iso like the one you provided on my pendrives and use them to make these two computers usable again. A flash drive would be always faster than hdds of this kind.
I know that I won't get WiFi and many other features but I don't care.
That's why I' m asking you if a "live Window 7" is faster than a "live Windows 10"
Thanks again!

You should have linked to that question so folks don't have to hunt it down.

P.S. Can I ask you what is the difference in terms of performance between a Win7 PE iso and a Win 10 PE iso?
Thanks in advance!
I've read about Windows Live USB's but never heard of anyone doing it. I think you are confusing the WinPE Environment with a Windows Live Session, like in Linux.

And, you should start a new thread for this second question IMO.

A flash drive would be always faster than hdds of this kind.

I don't believe this to be true, Especially on an old computer, because you don't have 3.0 capability. And, most Flash Drives are not as fast as even the oldest HDD's. A really fast flash drive is more expensive than a good SSD. You want faster, get a cheap SSD, 30.00 here in the us.

I would ask about one computer at a time and exactly what you are trying to do with it. Your Specs are lacking a Model Number. If you want to run Live why don't you just use linux for that? Create your own custom distro. Either way, IMO you will never get good performance or stability out of an OS on a USB, unless is is just a Live Session.