I just got off the phone to an Asus tech support person. By the way, I can't say enough great things about Asus support. In my opinion and experience, they are one of the last standing computer cos. where you can speak to someone intelligent who can speak perfectly good English, is very knowledgable and who will take as much time as necessary to resolve issues. I can always count on outstanding customer service.
That said, in my conversation with him, I would have to upgrade the following:
1.) ASUS Z97-A/USB 3.1 LGA 1150 Intel Z97 HDMI SATA 6Gb/s USB 3.1 USB 3.0 ATX Intel Motherboard: $118 after $20 mail in rebate from Newegg
2.) Upgrading my 450W power supply to a 650W: $90
3.) Water cooled CPU cooler: ~$100
4.) Samsung 960 Evo 250GB M.2-2280 Solid State Drive: $130
He mentioned that overclocking the CPU would give me roughly a 20-30% performance increase for roughly $300. I'm not sure how much more of an increase I can expect from the M.2 SSD but add $130 to that. At the end of the day, I don't think this is worth it cost wise. The average MKV file I am converting to MP4 is 15GB in size and I am compressing to a 3GB MP4 using high quality settings with the H.264 codec where the average file takes 2.5 hours to encode and if I use very high settings at 2-pass encoding, it will take between 5-6 hours. When I add several videos in the que to encode, it will take 1.5-2 days to complete. Unless my math with the numbers is off or I can expect a bigger performance increase, I think I'll stick with what I have. Are my numbers off here with amount of performance increase and estimated cost of some of the upgrades?