13" rMBP + 2 x 27" screens

My experience with dual Thunderbolts is no. Clamshell or not.

 

Sorry, but why it wont work?

 

it's not that it won't work, it's just that the question was will it work without lag. My experience with a 13" rmpb and twin thunderbolts is that it's laggy as heck.

 

ahh... I was guessing on hardware incompatibility, the HD4000 aint enough to drive 2x 1440p displays

 

Let's do the math here:

• If your displays are 1080p: 1920 x 1080 x 2 = 4,147,200 pixels in clamshell mode.
  
• If they're 1440p: 2560 x 1440 x 2 = 7,372,800 pixels in clamshell mode.
  
• Native resolution: 2560 x 1600 = 4,096,000 pixels if you only use the internal display.
  
• "Looks like 1680x1050" scaling setting : 3360x2100 = 7,056,000 pixels on your internal display.

So if you want to get a good idea of how it runs in clamshell mode with two 1080p displays, try the computer at default resolution on its internal screen only. The number of pixel to render will be roughly the same. It should actually run a bit better on the external displays than the native one since your computer won't have to handle HiDPI @2x assets.

If both your displays are 1440p, do the same but with the "Looks like 1680x1050" scaling setting.

I think it's powerful enough. Your main limiting factor will be the CPU anyway, not the integrated graphics. Mavericks will bring software optimisations that should make everything buttery smooth, until then you can use the Webkit nightly instead of Safari to make sure scrolling while browsing is fine.

 

On the math though, it's one thing on paper and another in the real world. Scale a 13" rmbp machine by itself to full resolution on it's own screen it lags.

 

i run 2 27" 1440p....NO LAG at all, you must have had something wrong somewhere.


stock 13" rMBP

 

When did you buy it? Is it a 2013 model? I've had the experience that for some reason, the 2013 models don't have the lag issues while the 2012 do.