I changed my Nvidis 8500GT to Radeon HD6450 and I have garbage ofter the grub stuff on both Mint15 and Knoppix7.0.5. Same problem if I live boot either DVDs. Mint 15 on my laptop is great with the Radeon HD6310 that's why I got the new pcb and that the 8500 was doing strange things. Any ideas? Ian