I have the exact same problem with Sapphire 1.0. Tried different Kernels. Also tried a complete reload, seems to help for a while. I did the dalvik cache route, and yes it seems to fix it, but it also doesn't seem to last as long before it starts to slow down again. Thinking about trying another ROM, but it sounds like this could be an issue with many ROMs.
Try disabling compcache if you have it running. A number of people (including myself) notice slow downs after a while when using the cache. I just avoid it and am much happier.
Thanks wingdo, I am running compcache, but I think that is what fixed (at least in my case and seemingly others) the screen redraws. Did you have redraw issues? Any chance you have a different solution for that?
I did have some screen redraw issues as well. Those appear to be gone as well, although you will still get redraws on occasion upon exiting a program if you are in a tight RAM situation (like leaving the browser).
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