I am having some very buggy obsidian mining...
Normally it takes 15 seconds to mine obsidian, but its only taking like... 2.5 seconds. but when I break it, the block re-appears instantly. it does this about 4-6 times before finally breaking into a collectable block.
Im not having any other lag issues with server/chat/other blocks
EDIT: Nevermind. Its just the Aether mod screwing it up client-side. thanks for the help, Alaskan!