you should get the 256 mb version of the gpu 17" because why not pay just a lil more and get the full experience also the 17" version is not underclocked but then 15" version is underclocked, I owned both and tried running games on the 17 inch and the 15 inch man you can majorly tell the difference 17 is the way to go. I am currently happy with the 17" not much problems here with this size. Always has been less problems on the 17 inch just like the powerbook generations 17" never had any problems. I also hear that its logic board is totally different beast.