OK thanks. Can anyone (St Bit?) confirm whether or not this occurs in yacoind? I'm having trouble replicating the issue, but I'm pretty sure it's a Qt issue. One potential solution is to load everything to a file and show just the last 50 transactions in the client.
Sorry, I can't help you.
I think it's just implemented not efficiently and normal users are usually not effected since they don't have that many inputs and/or a weak PC. For most people sendig it to a new adress should fix it. My netbook had it's first issues like this at around 120 transactions and currently it's not even capable of PoS minting.