Something is SERIOUSLY wrong with these machines. Long time Apple fanboy here. I'm so tired of this. I have a 16 GB, 512 GB 2.7 GHz early 2013 Retina. Over the past 3 months, I am now on my THIRD (3) rMBP. All three suffer from the same problems: scroll lag; graphics tearing; and problems when typing text into Safari or address bar. One lasted a month before exhibiting these symptoms; the other two did this right out of the box. NO programs/data were carried over from previous machines. Crispy fresh....FAILURES. Images in Facebook for example, will flicker, layover on top of others, slice in half or have other wacky image distortions. Sometimes these resolve after a few seconds, and many times they do not. As you type into almost any text window in Safari, many times the cursor will hop around, disappear, or show up at the wrong place in the word. Another fun thing is that as you type a word, say, "America", the text box (e.g. Google search box) will only display "Ameri". The "ca" is simply missing, although the cursor flickers at the end of the "America" and another static cursor will display after the "i". The problems occur in Safari. I am not running ANY other programs. A system this pricey should NOT have these issues. I should not have to download Webkit to seek resolution. Tell me I'm not alone. I'm one more replacement unit away from leaving the Apple family.