I am running hyperstaked on Ubuntu 14.04.2 LTS server, without GUI.
Even for pure POW wallets, I have noticed such behaviour when a lot of transactions have been received. Happened often during solo mining for coins with very low diff.
Yeah this is pretty much the case. If you have thousands and thousands of records then it will cause a bit of lag. I don't have any good way to prevent this that I can think of.
Can not reset the records?
You can consolidate unspent outputs by sending funds back to your own address, but this will destroy coin age (weight of the consolidated unspent output will start from zero). PoS splits an unspent output into two, so over time your balance gets split into smaller and smaller chunks. An unspent output of 1 x 10000 HYP becomes 2 x 5000 HYP, which then becomes 4 x 2500 HYP etc (note I have excluded staking rewards here)
If the wallet is super bloated then you may need to send all your funds to a new wallet.