Windows 7 vs windows 10 on an old pc

My dad has an old pc that one core 2ghz, integrated graphics and like 4gb of ram, its really slow with windows 7, would upgrading to windows 10 speed it up or slow it down?

I have an old Acer Aspire 5334 that I updated the Ram to the max of 4GB that it could take and installed an SSD for the HD and then upgraded to Windows 10 and it's like a brand new computer.

YMMV

only one way to find out 8)

Windows 10 would help its a lighter OS than 7, that's assuming it doesn't freak out because of 1 core.

There wont be much of a diffrence i think.
Linux distro with LXDE or LMDE desktop will most likely speed it up a bit more.

do you think there is a cheap pc i can buy i was thinking asrock beebox but i would also have to buy ram and hdd?

Put puppy linux on it and use 40mb's of ram...