Ever since I got Windows 10, and Ill also note, This same issue also happened on Windows 10 TP, Vanilla Minecraft worked fine. Minecraft with just Forge also worked fine. But, if I added a few mods (any mods, really), all of a sudden things go downhill. The loading screen would always get stuck on "Uploading GL Textures" for a long time, and after that, minecraft would only run at 1FPS, both in-game and on the title screen. The funny thing is, when it is raining, my FPS increases to 25FPS, I assume this might be because the rain is forcing the game to update the screen, but when its not raining, no matter what other condition it is, I get 1FPS.
Back on Windows 8.1 and 8, Minecraft worked perfectly fine, had a stable FPS, and hadn't been getting stuck on the 'Uploading GL Textures' part.
I decided to downgrade back to 8.1 because of this, but I really want to go back to Windows 10.
Also, this might be important:
The Issue only occured when Java 64bit was installed, Java 8 and 7. On 32Bit Java, The issue did not appear. I need my 64Bit java, so my only choice was to downgrade.
I've reinstalled my drivers and Java many times, even minecraft and forge.
My System specs are as followed:
Intel i7 4700MQ
Intel HD 4600
8GB Ram (dunno what exactly, my machine is a laptop which I never really looked up its exact exact specs for.)
If anyone has experienced this, has a solution, or might think this is a bug, please let me know. Thanks.