I'm having constant team fortress 2 ping spikes in ANY server I join whether it's 45 ping to 250 ping, and the weird thing is, my brother, who i bought team fortress 2 for his computer, plays any server 45-300 ping perfect, without lag at all!??!!? Please help his video card is a Nvidia GeForce 300 I think, and when I bought a new video card which I thought could fix the lag problem, they recommended a AMD Radeon HD 6670, which I am using right now. It solved the lag temporarily, but after 4-5 weeks of no lag, the problem happened again. First I freeze in one position but still able to look around, then it says auto-disconnecting in 25 seconds...
So to recap everything,
My brother's tf2 works great,perfect, while mine works very bad and laggy.
Specs:
Intel(R) Core(TM) 2 Duo CPU
E7500 @ 2.93GHz
3.50GB RAM
AMD Radeon HD 6670
Windows XP
It seems like it's not an internet problem more like my computer's problem. Please help