It depends completely on the server you're in, just go to browse servers and look for ones with sub 100 ping <3

If you're on Windows 7 or Vista, sometimes running:

• netsh interface tcp set global autotuning=disabled

in cmd can help. Sometimes Windows will automatically mess with your connection, and running that command will turn stop it from doing that. It could also be a million other things

You downloading something outside of Counter Strike: GO? If so...close it.....Also close any programs you don't need or aren't using for maximum connection

Stop downloading porn.

Maybe get some better internet, and join servers with low ping. Or try to unplug the internet for 5 minuts and plug it back in. IF you can do that of course.

I had very high ping in games when I had virus.

I haven't heard anyone else getting high ping like that in CS GO only. It must be something else running on your computer eating up bandwidth. Check the steam forums for more answers/others with a similar problem.

Yea try resetting your modem. Run a speed test see if it's your normal speed. Check you network and make sure while you are idle it's not still sending or receiving for no reasons. Also try servers with low ping to start with.

Have you tried actually looking for servers with low ping? Usually that is a search option. Either that or just random spikes in the amount of bandwidth other people in your household might be using.

Match making might've sent you else where for an evenly matched game. Try seeing if community servers will give you lower pings, servers closest to your position.