Hey banderos, Yes IRQ sharing does affect performance. While Windows is designed to allow IRQ sharing, and it's alleged to be fine with it, a lot of problems can occur when two major components share an IRQ. You should definitely have your graphics card, sound card, IDE controllers, etc. on separate IRQs. Go into your BIOS and reset the configuration and see if that helps. If not, go into Control Panel>System>Hardware>Device Manager and see if you can manually assign a free IRQ to the graphics card. If you can't (because there's none free, or it's greyed out), then free up some more IRQs by disabling things you don't use. Best to do this in the BIOS. For example, disable LPT/COM ports you don't use etc. Then reset your configuration so Windows will reassign the IRQs. This will speed up your bootup times as well as freeing up IRQs for critical devices. As for your second question, yes it will reduce your hard drive performance if you have a CDROM Master and a HD Slave on the same IDE controller. You should ideally have your Hard drive as the Master on the Primary controller, and CDROM as Master on the secondary. However if you have two or more CD/DVD/CDRW drives then always place your main hard drive as Primary Master, and your CDRW drive as Secondary Master, then the next CD/DVD ROM drive as Primary Slave, and finally if you have to, put the last CD/DVD drive as Secondary Slave. This will ensure the drive gets the full benefits of the highest UDMA mode on the host controller all to itself, and just like IRQ sharing, it reduces potential conflicts and hence improves speed and stability.