Here is some shorts from our friends at Puget Systems:
Processor (CPU)
While exporting video and generating previews in Premiere Pro can utilize almost any number of CPU cores, our testing has shown that for both 1080p and 4K video there is diminishing returns to having more than ~8 cores. Having more cores or multiple physical CPUs can still give a performance boost if you need the absolute best performance in Premiere Pro, but in general we recommend using a CPU with at least 6 cores and a relatively high (3.2GHz+) operating frequency.
Video Card (GPU)
Thanks to the Mercury Playback Engine, Premiere Pro can utilize your video card for a very wide variety of tasks. Not only will a good GPU improve the time it takes to encode a video, it can also drastically increase the amount of your timeline that can be viewed without needing to generate previews first. However, depending on what you are doing there is a point where a more powerful GPU will not translate into better performance. In general, we recommend a mid-range GPU like a GeForce GTX 970 for 1080p timelines and a GeForce GTX 980Ti for 4K timelines.
Memory (RAM)
While the exact amount of RAM you need is going to depend on your particular projects, we generally recommend a minimum of 16GB for all our systems. Memory usage in Premiere Pro can quickly shoot up, however, so it is important that you ensure you have enough system RAM available. The exact amount you need will depend on exactly what you are doing, but if you work with 4K videos or even very complex 1080p timelines you may want 32GB or more RAM.
If you want to read full article:
Recommended System: Recommended Systems for Adobe Premiere Pro