is this not my gpu?

That's the processor, I assume you have your computer in a place where it can't get much air-flow, causing the slow down to occur

it has a fan

having that fan obstructed by items, hell, including tables, will still cause the computer to overheat and slow down. I've had this issue myself

the fan is inside the computer

it gets air from somewhere? i thought it just blows

yea so it like blows the air