Hey there, B4Nd1d0s.
Basically what you can gain from a faster storage device for games is faster loading time.
The WD Blue drive is general usage HDD, which comes in models which are 7200RPM and 5400RPM (1TB+ models are 5400RPM). You should be OK with just gaming if you decide to go that way and if you're looking for a drive that's 1TB or less I'd recommend the 7200RPM model. The WD Blue HDD comes with a 2-year warranty and you can take a closer look at it here:
WD Blue Drive
The WD Black drive is our performance model. It's designed for more demanding software and gaming in particular. If you plan on recording/streaming while gaming, this would be a better choice. It has a dual-core processor and the 2TB+ models have additional features for better reliability, which you can check here:
WD Black Drive. The WD Black HDD has a 5-year warranty.
Hope that helps. Please let me know if you have any questions.
Boogieman_WD