Gamepainters, I had that problem with the (exactly) 500 ms in an old PC, when using two monitors. I remember it was corrected by returning to an older nvidia driver. In the PCs that I have now it does not happen.
I use a lot of timers, but they don’t seems to be the problem.
you are right, I think I have to test it in a new UDK installation, because in the current I have the problem even using a blank map with UTgame.
Maybe it is some parameter of the ini, which I modified a lot to do tests.
I have a copy of the inis before modifying them, I’ll test that before doing a new install. And I will tell you the result.
Thank you both for your help.