well as far as the resources go... i run windows 7 with a E6700 3.2 dual core, 8gb ram, with an 8800GTS gpu. I know its an older vid card, but i did not start to have problems with it until this update.
the image in which I had problems with (but was fine on the older version) was a paint.net file of about 18 layer. layers differing in transparency, and blending modes. 1920x1080. which is the size that i used to do all work in just fine. when i would load the file, even the layers window/box would take forever to load the thumbnail of each layer. like literally 30 seconds to load 18. another thing i noticed, when i used the magic wand tool, tolerance pretty much anything below 30 and global selection, it would not "finish" at all. a pop-up would show the progress, but it just continued to go over and over. eventually after about 20 minutes, i had to kill it in task manager. clicking the close button did nothing, and alt-f4ing did nothing. reopened the image, took forever to load, same problem with thumbnails, but decided not to use the magic wand. instead i would choose a selection, then ctrl+drag to select more. after doing this 3 times, it became extremely laggy and would take at least 20 seconds to actually "select" what i selected. sometimes it wouldnt even register that i clicked and dragged at all.
Like I said, I know its an older GPU, but I have never had any problems at all using the older version. not once. Never crashed, never experienced lag, never had any issues. I love Paint.net. in my first post i stated that it is the only program i use except for one other. I have used it for years. I really am saddened by this whole situation.