Wireless Adapter drops outbound with high output?

I am using a Rosewill N adapter:
Newegg- Rosewill RNX-N180UBE Wireless Adapter IEEE 802.11b/g/n USB 2.0

and a TP Link router (also have Linkysys WRT w/ Tomato).
I have Cable internet.

I recently moved to an apartment and it my connection tends to drop during these times:

Two PCs playing online games.
During Torrents.

It will even drop while one PC is playing a game.

The connection to the router does not drop, but I cant ping anything from my PC.
I can ping the router (1-5ms).
I can log into the router and ping websites. i.e. google (~20ms)
I can NOT ping google from my PC.

With torrents, what tends to happen is the increase download speed reaches an apex, then slowly drops as my connection losing pinging capability. i.e. downloading at 2.0MB..drops to 1.5, drops to 1.0 drops to 700..etc over about 20seconds. I will regain access to the internet after about 10min usually.

I'm trying to diagnose this problem. I know I could of moved into a higher interference region, but given I can ping my router just fine, it doesnt make sense that its an interference issue. It never says I'm not connected, I'm always connected, just cant reach outside my gateway. I also dont think its the router because I can login to the router and ping google fine while my PC cant get out. The last piece I havent tested is my cable modem, which was provided - its a Motorolla sufboard? dont know model.

Can anyone think of another way to diagnose this? What could it be?
I don't drop connection to my router.
My router doesnt drop connection to ISP.

I.E.
PC to Router - just fine.
Router to Internet - just fine.
PC to Internet - intermittent.

It's not always an issue, but when it is an issue, especially during an online game, it's unbearable and makes gaming online a pain and a waste of time.