I can’t see theself chat in Team Fortress 2

I had a Ralink based Wireless card too and in particular with Windows 7 I had plenty of problems. High ping, disconnections, and so on.

My first suggestion is to try to connect directly to the modem with an Ethernet patch, only to verify that using this connection the ping problem is solved.

If it helps I can say that in my case I solved the problem without doing holes around, but I simply bought a couple of Netgear Powerline/Ethernet Adapters that worked perfectly.

I suspect that you're hitting your real RAM ceiling and your machine is swapping when you're loading or connecting to games. I'm guessing you're at 4gb - I sincerely hope it's not less.

To confirm, open up Activity Monitor (Applications > Utilities) and go though all the steps of loading and connecting to a game. Switch to Activity Monitor while you're in a game, your System Memory will probably have very little "Free" memory left.

You can attempt to free up more RAM by quitting other applications that are running when you're playing TF2, but I suggest upgrading to 8gb (if your machine supports it). It's under $100 and makes a huge difference when doing all sorts of RAM-hungry stuff (photoshop and parallels at the same time? not a problem!).

Or, you can try to adjust the settings down to a more manageable level for your amount of RAM. Lowering the texture quality is probably the easiest way to achieve this, but try out the rest of the settings to see what works for you.