I’ve asked this before. I’ve noticed if my speed is slow, and I test it a few times, (I usually use the Netflix-owned site,) my speed rapidly improves. Do ISP’

I’ve asked this before. I’ve noticed if my speed is slow, and I test it a few times, (I usually use the Netflix-owned site,) my speed rapidly improves. Do ISP’s throttle service, DETECT your visit to speed testing sites, and THEN speed things up?