Premiere 5.5 chugging with Mercury GPU on. This started when adding Kona LHe+ In Out card.
It may be I just don't have the computer power.
Nvidia Quadro 4800
8 gigs ram
When playing sequence 720p with P2 footage and Dynamic Link After Effects compositions and a yellow reference line the system chugs and shows down. I thought the system would analyze and request a render. If I turn the Mercury engine to software I get red reference lines, after rendering sequence plays well.
Hardware acceleration will keep your Dynamically Linked comps yellow, even though they may be very difficult to play. This is normal. If you need smooth playback of comps inside of PP, you'll have to render the sequence they're in using the "Render Effects in Work Area" command under the Sequence menu.