Hi, again. I did some reading on amd's site, and if the disconnect + apic fixed the same problem as the ~500ns delay, then it could be as i suspect... I suspect that something goes wrong with apic ack when the cpu is disconnected and according to the amd docs we could check the Northbridge's CLKFWDRST or isn't that avail on the outside? (It would be interesting to see if that fixes the problem as well.) http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/26237.PDF I don't really have the knowledge but it would sure be nicer to fix this by checking this than to just disable it. I dunno if there is something we could do from within the kernel aswell with the sending of HLT but i doubt it. Anyways, we need a generalized patch that does better checking on the NMI bit (like Ross' patch). PS. Anyone that can point me to northbridge tech docks? and CC -- Ian Kumlien -- http://pomac.netswarm.net