Hi,
Stating FPS as per the Best Solution isn't ideal as it is proportional to your existing performance. What you really want is to see the AVERAGE performance:
60% or 1.6X the frame rate on average:
http://www.techpowerup.com/reviews/MSI/GTX_960_Gaming/29.html (compare STOCK 970 to 960 which is 58% at 1080p and 62% at 1440p average over about 20 Games)
Since you have a good CPU these will be very accurate.
Thus, if getting say 40FPS in a game you'll get closer to 64FPS at the same settings. That's 24FPS improvement for this example but if you were on a 144Hz monitor (probably not) then it could be over a 50FPS improvement for a game at a high frame rate.
As for saying more than 50FPS makes no difference at full HD that's just silly. For example, regardless of resolution if you want VSYNC ON and want to stay above this (to prevent stutter) then getting to 60FPS is very important.
Also, if you aren't at the highest settings this enables you to turn up the quality. Frankly, i have no idea what the HD/50FPS comment is supposed to mean.
Anyway, getting a GTX970 is also going to be a bit of future proofing for more demanding titles. In general, games are heavily tied to CONSOLE releases so we get a surge in required GPU and VRAM requirement. Not all at once, but overall. We saw this with Watchdogs when it optimized for console and had VRAM issues requiring 4GB initially to prevent stuttering.
If you have only 2GB of VRAM you will have problems running some future games.
Summary,
- 1.6X the performance on average
- if it is "worth it" is up to you.
Other:
Learn what Adaptive VSYNC is and how to use it. Basically it's for when you want to prevent screen tearing, but you also drop below the target (which causes stuttering with VSYNC ON). It also fixes the issue in a few games that auto-synch to 30FPS if you can't output at least 60FPS (like Max Payne 3).
Thus you get screen tear if you drop below 60FPS (for 60Hz monitor) but not stutter.
Adaptive VSYNC should be enabled per-game via NVidia CP-> "Manage 3D settings-> Add game-> Adaptive VSYNC-> Save"
(normally I would adjust visuals to prevent dropping below 60FPS when using VSYNC. Now i can raise visuals slightly higher since periodic screen tearing is far less of an issue to me than stutter)