I previously ran benchmark tests comparing Adobe Lightroom 4 performance between a mid 2009 MacBook Pro and a mid 2012 non-retina MacBook Pro. It’s worth going back and seeing the difference in performance between Adobe Lightroom 3 and 4.1. Again, I will benchmark time to render 100 1:1 previews and export 100 jpegs from a Canon 5D. The tests were run on a mid 2012 non-retina unibody MacBook Pro 2.3 core i7 and again on a mid 2009 unibody MacBook Pro 2.66 Core 2 Duo.
In my test, Lightroom 4.1 is slower than Lightroom 3 but less so with the newer processor. On the 2009 MacBook Pro, Lightroom 4 is 15-18% slower than Lightroom 3, but on the new 2012 model Lightroom 4 is only 10% slower in these benchmarks. I’m not sure why this is the case especially considering the new 2012 model has only 4GB of RAM.
These test measure the performance of preview rendering and exports, but what about the general performance of Lightroom 3 vs Lightroom 4? I know that with my 2009 Macbook Pro, the Develop module was rather useless once any brushes or retouching tools were used. The machine would hang to a halt. On the 2012 non-retina MacBook Pro, these tools keep up with my speed of work.
So if you have upgraded to Lightroom 4 and it feels slow, you are correct. Upgrading to a newer hardware will surely help. Going back to Lightroom 3 wasn't an option for me because Canon 5D Mark III files do not process in Lightroom 3.
If your curious to see how your machine compares, please read my previous post on how I set up my benchmarking test.