There can be many reasons for a bad browser performance. Many open tabs are never a good idea, especially not when there are heavy scripts or browser plugins being used in background. It could also be related to old graphics drivers or a very old pc. I noticed that my browser gets really slow when I have the Steemit Market opened in background. You could try to only open new tabs when you really use them.

The issue regarding the 'comment_options' operation only occurs with Steemit's own nodes. Their nodes return random numeric values in the field 'percent_steem_dollars' and not the actual value from the blockchain. Since I build a hash sum of the data for each operation to detect new operations, the hash changes with each refresh and SteemWorld can't distinguish between new and old ops. (reference: https://github.com/steemit/steem/issues/2912)

I have now fixed it temporarily by changing the value of that field to a fixed '?' so that the hash won't change for the same operations.