I registered just to say THANK YOU for this topic. I returned to KSP after a break (was previously playing 0.24) and after updating my mods I found that I've reached the memory limit. Tried the 64bit, but found it too buggy and some mods would not work (I understand the authors disabled them on purpose in 64 because of the version instability). I managed to reduce my mods to make it somewhat playable, but wasn't enjoying it, because I knew I was missing on gameplay. So was ready to throw the towel and wait until the 64bit version becomes more stable. Then I found this topic, and after switching to openGL I went from 3,2GB+ of memory usage to 1.8GB. No issues so far and I can enjoy KSP to its fullest potential. Thank you.