Quote from DoomTrooper :

just incase this problem couldn't get anymore bizarre i have found a solution
as long as i have windows media player running in the background, doesn't matter if it playin music, the ping is fine with force feedback, i guess its a solution but a strange one at that

Holy hell. Why does that work????

I've been searching high and low for a suitable solution to the lag issue without removing FFB... arg. (BTW, it's not just wheels, it also happens with Logi's Rumble Pad).

Thanks DoomTrooper!!! IT WORKS!!! Why... dunno.

I've quoted you in a post over at RSC: http://forum.rscnet.org/showthread.php?p=2677392#post2677392

I haven't tried the spybot thing yet.

I can confirm that removing Logitech Gaming Software fixes the "every 5 seconds" lag issue for me.

BUT... it also disables Force Feedback to my controller.

I'm going to go to Logitech and download the latest Logi Gaming Software, reinstall, and see what happens.