Small update!
Looks like you were right, once again, Freddie!
It was a nagle issue and a recurring 'CPU situation', appearantly you can't take manual steps to fix this in the registry, the change has no effect.
I found a patch to download and install though and also created a .reg file for TcpNoDelay thing, don't know if that really works then either but did it anyway.
Result? The following;