I just want to add that I have installed windows 10 21H1 over win 7 on 2 laptops and 3 desktops.
One laptop was really not ideal and is slower now. Whereas the other (an I7) is screaming fast.
Similar mixed experiences with desktops. 32 GB ram seems to be the sweet spot for speed with the less ideal MOBO and older processors.
Here is a little record of those....
On a fresh, superfast build, with win 10 1904 installed, when I upgraded to 21H1, I lost jump menus on the taskbar. But she remains superfast.
I have not solved the jump menus yet If not fixed with 21H2, I will fresh install... I have done a non distructive repair reinstall and DISM / SFC. Reset menus... No luck.
Processor AMD Ryzen 5 3600 3.6 GHz 6-Core Processor
MOBO Asus TUF GAMING X570-PLUS (WI-FI) ATX AM4 Motherboard
Installed RAM 48.0 GB
System type 64-bit operating system, x64-based processor
This old desktop is ok, but I bet 32 GB would be far better!
Processor AMD FX-6300 Six-Core Processor 3.50 GHz
MOBO Gigabyte GA-970A-DS3P ATX AM3+ Motherboard
Installed RAM 16.0 GB
System type 64-bit operating system, x64-based processor
This desktop is a borderline one and is slower now, also think 32 GB would make it nice.
Processor Intel Pentium G850 2.9 GHz Dual-Core Processor
MOBO MSI H61M-P31 (G3) Micro ATX LGA1155 Motherboard
Installed RAM 16.0 GB
System type 64-bit operating system, x64-based processor
Whereas this desktop is a super capable workhorse and I think would easily speed up with 32GB
Processor Intel Core i7-4820K 3.7 GHz Quad-Core Processor
MOBO MSI X79MA-GD45 Micro ATX LGA2011 Motherboard
Installed RAM 16.0 GB
System type 64-bit operating system, x64-based processor