Corran
Well-known
When I was still using windows I would reformat my drives every 6 months just to get the computer running at a reasonable speed.
Running both stock and custom-built PC's for over 15 years and I've never, ever had this kind of issue. Friends/clients that report such problems usually stuffed their main HDD up to 98% capacity or tried to run new tech or high-end software with low-spec machines and say it's "the computer's fault."
A properly-built and tuned system will run perfectly, regardless of OS. I built my latest Win7 box over 3 years ago and it's still running like the day I first booted it.