Lol! The only way your computer could run close to 50 civs without a slow down is if you had the following. A octa-core computer. Yeah, 8 cores, 400 Gigabytes of ram, Vista/Windows 7 64-bit ultimate whatever special name Bill Gates came up with..., a video card that literally can't exist for 40 years, oh, and maybe each core has to be about 500 times faster than the current computer processor.
Sorry, but bottom line no computer can run this mod with 50 civs, or 48, or 24 even, maybe 24, without lots of MAFS.