Thanks OP for the post. I have been a PC user and ordered my first MacBook Pro 13 retina last week. I found the same issue earlier and thought there was a problem with software/ hardware. Honestly, I expected there should be no problem from a new Mac, especially we're talking about a basic and simple task like browsing sites such as NY Times.
After days I noticed the screen would freeze and a beach ball coming up and spinning, even when browsing without "tapping to zoom" while scrolling. Moreover, when I opened and viewed PDF files, the scrolling of screen was so LAGGY that I couldn't work at all. This is really frustrating and I doubted if my laptop was defective, and I ended up returning it.
Before return I read through lots of threads in this forum and also in various sites, in hope of finding similar problem and solution, I was deciding if I should buy 15" with GPU.... Now it seems to me that it's indeed NORMAL?? The problem running Safari is dealt with the solution installing WebKit. But what about PDF?? @OP do you have similar problems if you zoomed and scroll with a PDF File?
I was about to order a 15" rMBP and give it another try, until I read this thread today....... Can you or any other users elaborate their experiences on that? I mean besides Safari, any similar "zooming and viewing PDF document" scrolling problem like mine while viewing with a 15" rMBP?
Many thanks on that and I appreciate very much for other comments.