About 3 weeks ago I upgraded my internet, replaced my modem and switched from connecting via dialer, to a fixed connection.
Since then I've been experiencing odd ping spikes during certain hours.
Sometimes it's during noon and evening, other times it's morning and late at night, and sometimes it's 22 hours a day.
It only affects Counter-Strike 1.6, Counter-Strike - Global Offensive, Source, CZ, Team Fortress 2 and Quake Live.
Other games I have, such as Battlefield 3-4, bad Company 2 and Planetside 2 are unaffected.
Browsing the web is also unaffected.
Sometimes I can reset my modem and pings return to normal for a few minutes before spiking again.
When I run command prompt and ping those servers, latency is normal, between 60 and 80, but in-match and on the server browser they are much higher. 
I'm trying to understand why it's these games but not others, and why is it when I ping them latency is normal, but in-game it's much higher.
My ISP and infrastructure provider have been zero help thus far, I've mailed both and they've yet to return my mail.
So fucking annoying.
"I think Call of Duty resonates because it's believable and relatable," Sledgehammer Games cofounder Michael Condrey says.
Believable and relatable...Yep, sounds like Call of Duty
