I am running stock rooted FRG83G on my OG droid. I got a notification from Verizon that an update to FRK76 was available. I got the stock rooted FRK76 ROM from Peter Alfonso, made a nandroid backup, and flashed the update to my phone. Unfortunately, my phone refused to boot after that, and I had to wipe everything and restore my FRG83G backup to recover. I also wiped my cache and dalvik-cache after restoring the backup.
My question is: why does my phone run a lot faster now? I was getting pretty frustrated with how laggy everything on my phone was getting, and was considering upgrading my phone for that main reason. Now, I don't see a need to upgrade anytime soon. I've read that wiping your dalvik-cache and cache speeds up your phone, but I'm wondering if anybody knows why this is the case. Is it buggy apps that leave crap in there? Is there any way to avoid unnecessary stuff collecting in cache/dalvik-cache and slowing down the phone? Is there anything other than wiping the cache/dalvik-cache in the above procedure that would have sped up things on my phone?