I'm running 8GB GPU, 3.6 Hz Processor, 8GB RAM on an HPz420. I upgraded recently from a mac because I only had 2GB Video Ram on my mac and was expecting better playback from my RAW 4k Production Camera. But I still can't play it back at all, red bar across the whole top. Even when I switch it to proxy mode it still isn't playing back smooth. I've very confused so trying to figure out the best settings. Thoughts?