Hi. I'm looking at upgrading my GPU. Currently I gave 2 GTS 450 in SLI. However I don't game a lot and would like to get one card that cuts the mustard. What I'm really after is a fairly quiet card for High definition video. I use MPC-HC with Madvr and I'm looking into really pushing the processing power of Madvr. GPU upgrades I'm considering could be new or second hand ; Gtx 960 / 970 Amd rx460 / 470 I'd welcome your thoughts or experience in this. By the way I'm using a 500w psu which I'm not upgrading right now. Thanks.