I was just starting to test PhotoShop CS6 to see what new stuff it has to offer, and although I’m not a designer nor use Ps in a way that may consider as “testing”, I use it regularly and find it very useful. Anyway, one of the new stuff that has blown my mind is the new PNG compression. Meaning that each time that you want to save a PNG image, you have the option to compress it (which is the default setting on Ps CS5), or save it faster by not compressing it (for big images). It makes a huge difference.
Here are three images. The first one is using Ps CS5, the second using CS6 with compression, and the third one CS6 without compression.
So far, so good. Also, it opens faster than Ps CS5 and seems to use a few less resources, but that will vary per PC. In any case, I recommend you to download it and try it out.