Hi Andre, Well I seem to have finally fixed my endless DPC problems. I performed a fresh install of Windows 7 and carefully installed all drivers and updates for everything in the following order: - Asus motherboard drivers - Flashed the BIOS and reinstalled latest vers. - AMD CPU drivers - All Windows 7 important updates incl SP1 - GPU drivers - and lastly, the drivers for the external firewire audio device. Hardware wise, I changed the slot that the GPU was installed on. I had it in PCI slot 3, and on reading the manual, they recommended slot 1 for the GPU. I also removed an Astrotek PCI firewire adapter card which was not being used. Something in that mix of changes was the secret sauce to fixing the DPC problems. Now I can run video, audio, flick between screens rapidly at any resolution and DPC never peaks above about 153. I've even still got aero running. I've got fingers and toes crossed that this remains stable, but this is the first time I've ever had Win 7 so calm since first installing it 18 months ago. I was never able to install and run my audio production software through Windows 7 due to these issues and had a dual boot machine so I could run XP side by side. Now I'm going to give it another go and see if I can run everything inside the one O/S. Many thanks for all your help Andre. Really appreciate it.