I recently bought an aspire s3 ultra book. I plan to hook it up to an external monitor, keyboard and mouse when I am at home. So I will have the lid down. However I was reading that it sucks air thru the top keyboard and out the back to cool it down. If I have the lid closed when I have it hooked up to external monitor, keyboard and laptop wont it cause it to over heat because I will be blocked the airflow ( lid will be covering the vent that sucks in air ).