http://askubuntu.com/questions/51310/the-daemon-is-being-inhibited-error-message-when-mounting-volumes-on-a-partiti
Try reading the topic to see if that's exactly your problem.
What I see here is that the only difference (that really matters) is the GPU company. My question to you is, is the amount of RAM more important than the GPU company? (AMD vs Nvidia).
With laptops, you have limited capabilities when it comes to configurations in your BIOS. My laptop, is stuck at 215Mb VRAM. Sorry but there is no work-around for this.