Troubleshooting incredible lag despite good ping

Hey guys, I just need some input real fast.

In a recent game, the entire game for both me and my roommate (located in a university on the east coast) was plagued with incredible lag, despite having a decent ping. I just wanted some feedback as to whether this lag is affecting others, or if it's just my connection.

For context, we normally run an average of ~86 ping. This game was constantly around ~115, which isn't that bad for east coast either. We are both connected via ethernet.

However, the lag experienced was akin to having ping in the upper 400s. Response time was slow, and skillshots were impossible, the game often freezing up in the midst of a teamfight only to see everybody's abilities all firing off at the exact same moment, with champs warping around the screen in a massive explosion of confusion. Despite this, our ping never went above 115.

I alt-tabbed out of the game and ran an internet speed test. These are the results during the game.

http://www.speedtest.net/result/4080696369.png

So my question is basically, is this just massive packet loss on Riot's server end, or is this something with my internet? I'm trying to troubleshoot.

Thanks! (Didn't know which board this goes in, so I put it here)