I got a new computer last year running Windows 10. It's a custom build and very decent.

Blitzkrieg 1 runs fine on it, but I've tried Panzerkrieg and Blitzkrieg Mission Kursk on it and while they both work the gameplay is really jerky and not smooth. I've tried changing the speed and resoloution but nothing has worked. Does anyone know a fix for this?

I've started playing Blitzkrieg about 2 weeks ago and it was always quite jerky, still playable though.
Yesterday Windows (Win 10) did an update and now it's running perfectly smooth. I don't know what happened, if it really was because of the Windows update.
I'll check out the other games in the series soon.

It's an odd quirk, but other players have reported that restarting your computer tends to fix this issue. For whatever reason it seems to be related to your computer's uptime. I haven't heard of any more permanent fixes so it remains an annoying, but generally solvable problem.