I'm using a built-in 780G (HD3200) as well with Phenom triple core. With MP 1.00 I was using vector adaptive and PDVD8 codec with no problems.I've been using a 780G with amd dual core ht3 procesor (forget which one) and it does TV3 1080i no problem. Using vector adaptive and Powerdvd 8 Codec with hardware acceleration enabled
Since installing MP 1.1 I've not been able to use vector adaptive. The highest I could go was Bob deinterlacing for 1080i without stuttering. Since updated to PDVD10 and can now use plain vector but not adaptive. But it still looks very good to me.
This is a Vista PC. What is your Windows version?