I used to think that the graphics card was the primary thing followed by memory when video editing. But I have found the following works better in my experience- as I am sure you are aware, but for others here is what I have found works:
1.) Get the fastest CPU you can. A dual core will do- but a quad core is even better. Think Intel i7 Quad or AMD equivalent.
The CPU is what does most of the work in editing and various other computational needs such as rendering.
2.) Get as much RAM as you can- a bare minimum 4 GB - 8 or more is even better. Also keep an eye on the frequencies, faster is better- so many choices out there- gets confusing to the average user. (I am using Corsair Vengeance RAM as an example.)
3.) Graphics card- it does not have to be the latest greatest, but depending on your budget, try to get a good one. Research and price match til you are satisfied. Any modern GPU is much faster than what was out 5 yrs ago and can handle almost anything thrown at them.
4.) Hard drive- an SSD is nice - but pricey right now. So a fast, large hybrid or mechanical HD to store and edit your video is a good call.
(I am using a hybrid- Seagate Momentus XT 750 GB right now- which has really fast boot times- but does not touch an SSD in terms of read / write performance. But dollar to GB capacity was my concern- so I will wait til SSD prices come down a lot more.)
5.) A good quality IPS or equivalent Monitor. Yes this somehow becomes an after thought. But seeing how the video should look is worth the extra cost for me. (my personal choice, price to specs ratio compared is the ASUS ProArt 24" model line.)
Of course- motherboard, power supply etc if you are building your own drives up the cost. I like some of the manufacturers that allow you to choose the components and they build it for you. (I have personally switched to laptops right now though, working great so far.)
Rob
PD 14 Ultimate Suite / Win10 Pro x64
1. Gigabyte Brix PRO / i7-4770R Intel Iris Pro 5200 / 16 GB / 1 TB SSD
2. Lenovo X230T / 8GB / Intel HD4000 + ViDock 4 Plus & ASUS Nvidia 660 Ti / Link: https://www.youtube.com/watch?v=ZIZw3GPwKMo&feature=youtu.be