I've seen the slow networking situation in my part-time job at a PC shop.

It's the same reason two newly-installed machines have been on the net for a short time, and one's slow, the other fast: the fragile operating system (Windows).

There's a great deal of money in the business of viruses; the last I heard there was a bounty of $0.06 per CPU for machines a virus writer can put under control of the guy paying the bounty. It's because he can then use it to send spam. Enough of these, and they can send unstoppable amounts of spam, more, and no password is safe: they can brute-force or decipher them.

The next level of the scam is that antivirus software. Well-known names you'd think were best, are so well known the virus writers put in code to turn them off. Lesser known types have a questionable value, including the far end of that spectrum that remove most viruses and install one of their own! These usually are advertised as "double speed" and "something-sweep".

Networking, which doesn't involve any one kind of OS, is pretty easily measured. There's a bandwidth available, and a latency. If you can get your networking to an ethernet cable, you'll be able to swap your slow machine to someone else's machine and run one of the many speed tests out there.

When you get tired of all the slowdowns, the virus circus, paying people $100 to clean out your computer, and most importantly fiddling with it, drop me a line and we'll talk about Linux: the sane alternative.