Lag with rMBP

That is pretty hard to answer, knowing nothing about 10.9 and now haswell on the market yet. You'll just have to wait and see

 

I understand that sentiment, the scrolling improvements WebKit nightly introduced should have been ready a year ago when the rMBP launched.

At that point they already saw the need for scrolling performance improvements, that's why they decided to start using Core Animation scrolling in Safari 6, but clearly that wasn't enough. They may have overestimated the resulting performance gains.

The WebKit nightly is a testbed for stable versions of Safari. Those improvements will undoubtedly come to Safari, it's just a matter of when. I'm surprised it's taking this long. Releasing with 10.9 seems like a likely timing, as new OS X versions often come with new Safari features.

I'm pretty confident it will be fixed when 10.9 is available, but that it has very little to do with Haswell. A software fix is what we need. You could temporarily use WebKit, but be aware that it crashes sometimes, that iCloud syncing doesn't work and that not all extensions work.

 

I am always using integrated video card on my retina (HD 4000) and everything working SMOOTHLY! Including scrolling. I am using google chrome. In safari everything smoothly too.

 

what is lag? I don't see anything lag on my 2 weeks old rMBP…did I miss something?

 

yes you did. There are tons of threads about this issue :/