Nope! I tried
App.UseVerticalSync (false);
App.SetFramerateLimit (0x20);
this
App.UseVerticalSync (true);
App.SetFramerateLimit (0x20);
this
App.SetFramerateLimit (0x20);
and this
App.UseVerticalSync (true);
on 2 differant computers, and it still maxed out the CPU at 100%