Premiere Pro leverages on CUDA/GPU via Mercury Playback engine so if your projects are large enuff and budget willing perhaps you may want to look at
X6 + 8GB DDR3 + GTX 460? Mobo could even be 870 chipset
A case for GPU computing: Adobe Premiere Pro CS5 and the Mercury Playback Enginehttp://tech.icrontic.com/articles/reviews/a-case-for-gpu-computing-adobe-premiere-pro-cs5-and-the-mercury-playback-engine/
This project consists of compressed 640×480 video footage. These small video files were being eaten alive by the massive 1090T hexa-core processor and 8GB of RAM. Premiere Pro CS5′s increased performance with multi-core systems coupled with bleeding fast hardware will make fast work of any simple projects such as this, not giving the GPU enough work to really make a difference. These results do suggest that if you’re editing small-time video footage, you will not benefit much from using Mercury Playback.