did you check the drivers for your graphic card? i had a similar problem when playing grepolis, and it was a driver issue. but browser games require less i guess.
I have the latest drivers installed.
and my GPU have 2GB memory and i play on 1920x1080.But even though i decrease the resolution the game only givesaround 19fps but sometimes the fps goes aroun only 5.
Remove your current gpu drivers, clean the registry then re install them.
Also, monitor your temps, with Hw monitor. Might be throttling down issue, btw 48 c ambient ?