So you are basically saying that the experienced drivers developers are wrong when they detect that it's not their fault and even tell you the reason why the game has bad performance? I have i7-2630qm with Intel HD Graphics 3000(Sandy Bridge processor), and I know for sure that Sandy Bridge drivers are performing very well and are developed very well by the Intel engineering team, but the game is still lagging on this pretty powerful integrated graphics processor... Intel HD Graphics 3000 can run some pretty graphic intense games...
There is one more problem, on install on Ubuntu(from the deb file) the game(/usr/local/games/cogs) is not added to the PATH variable and you can't call it from terminal for example... Good thing the find command is extremely fast... I ran it on my nVidia GT 540M external video card and it runs good...
I didn't intend to be rude(It kind of sounds like this, so...), I just wanted to make my point that the drivers are not really the problem(in case of nVidia card it is just to powerful to lag).