Totally agree with networks.
You've got a 3 y/o battery now running an uprated gfx chip on a new mobo in an old machine, which only used to give 1 hr of life on batt. with the old mobo?

Gaming and batteries just don't go well together, especially an old battery that's on it's last legs lol.
You should get a new battery, 1 hr of life is poor to start with but you're loading it even more.

You say your drive is 3 y/o, you should back that up anyway, but I'd plump for the batt.
S