in august mincraft had a update,... and skyrime had a update... and the drivers focused on skyrim which took away fps from MC cause SRim renders difrently and was more popular than MC so they wieghed it out and otmized for SRim. smh aholes ....
anyway the sametime MC had a up date which included shadowes and ALOT more textures,so it was sorts not good for any one.
even the high end people had problems with talking like 980 & and 970 peeps,
+java 51 update sucked too just extra info.
so now, i found a page to that will explan what to turn back off and the performance dramticly decreseses like the shadows for all 1000000 thousand grass blades is just sucks.
https://shotbow.net/forum/threads/low-minecraft-fps-must-read.292552/
and you may also need to alot more RAM to mincraft cause standard only comes with 1gig but since more textures you need to aalote like 2 gigs of ram for it to run.
https://www.muttsworldmine.com/forums/topic/136-allocate-more-memory-to-minecraft/
^^ more ram for textures!
+you need to go in to the bios of your board and and turn your intel grafic OFF, other wises MC will grabe the next best grafics it finds and INTEL 4000 in that case would be the closest and would then be redirecting it to you main GPU which is a BIG hassle for a PC to do. so go and TUEr you CPU gpy 4000 what grafics off in the bios as well and make sure v syce is off in the MC game as well. no just the controll panle.
and update your java. may help.
i dont even play MC but i just studied it in like 5 min and could write a book about it. it must be a pain to play lol.
as for COD for frame rate with updates may vary is normal and relatively decent for your system, i wouldn't worry about it too much. frames go up and down just turn like HDR off and LOW shadows. with light " terain" and you will be able to play fine shit gets in the way any way during competitive gameplay.