Anand said:
"Remember at 2880 x 1800 there are simply more pixels to push and more work to be done by both the CPU and the GPU. It’s even worse in those applications that have higher quality assets, the CPU now has to decode images at 4x the resolution of what it’s used to. Future CPUs will take this added workload into account, but it’ll take time to get there."
To me it won't just be Facebook. It seems to be any applications that has higher quality assets. Facebook is just one example. Many other websites out there that people could rely on. There are lots of productivity web applications, like project management web apps and so forth.
However, Anand said on Mountain Lion, he did get better fps (primarily due to Safari be coded to use the GPU more 'Core Animation'). The question here is will the user notice the difference between 30fps and 60fps scrolling or other common UI things. If they don't, then they won't notice a lag.
Also note, The geek bench scores for Retina and non-retina MBP are virtually the same with the same processor.
However, in the real world usage, where you might have multiple websites and applications running. Would the retina display slow down your productivity
since, the display itself might be using some more gpu and cpu time, instead of the other applications, as compared to the non-retina version with the same specs.
That is what should be tested.
A good test might be
-importing a raw image in Aperature
-having multiple websites open, twitter, quota, Facebook, youtube
-playing a 1080 HD
-Doing something processor intensive on Photoshop at the same time.
-Writing a presentation in Keynote
-Writing a document in Pages
All happening around the same time.
Then running some benchmark like Geekbench or sometime of GPU benchmark while the above is still happening and seeing the delta between the rMBP and MBP.
If there is less than a 15% difference between rMBP and MBP and there is no "noticeable" lag between the two.
Then the rMBP wins.
Also adding an additional monitor while doing the above; well that would be a good test. Stretching the GPU a bit further.
It does sound like a mixture of software and design. The interesting part though is it performs better for 'real' applications and games. I think most early adopters would be ok with Facebook not being optimized if it means that their games, video and photo work aren't impacted.
If they aren't, then returning it and waiting a couple years is an option.