I bought some days ago the MacBook 12" base model. It has an excellent screen - in my opinion even better than rMBP’s screen. Absolutely no high pitch noise when SSD accessed. I love the keyboard and the touchpad. However, the performance… Even simple pdfs could not be scrolled smooth, e.g. this simple pdf http://store.storeimages.cdn-apple...._finance/terms/apple_consumer_finance_tcs.pdf - scrolling in Safari is sluggish and not smooth, even if the window is not in full screen mode. Is it a problem with my MacBook or is it a general issue in Yosemite?