Check you power management profile settings. I was having this exact problem a few years back, and somehow my power profile settings were switched in some sort of upgrade/windows stuff install, and the symptoms were similar to yours. I would get huge spikes in ping to the HTC game server while playing, resulting in much lag and warp on my end, yet my connection at the time was 20mbit and very stable so far as other general net related tasks.
Go into your power profile, and see what you settings are. I remember when I was having this trouble Skuzzy told me that in laptops this was a very common problem as the power management stuff was a nightmare back in the xp/vista days, and it turned out my OEM cheapy desktop at the time had the exact same issue. Once I put it into a gamer/full power profile, all my trouble went away.