RPC seems to take forever verifying blocks.
I agree. I've tried searching/reading on it but I can't find an explanation for this.
Is this a problem with HashCows?
The difficulty change with RPC takes 720 blocks (target time of 1 day per difficulty setting). The Dev of that coin didn't know about multipools when he designed the coin, so when the diff goes low, we all jump on the band wagon (this happened Sunday night in the USA). The blocks then get mined WAY to fast, the diff goes high, and everyone jumps off. We're talking swings from 5 Gh/s down to 500 Mh/s. At 120 confirms, the coin takes forever when the difficulty is high and we're not mining it. In the last 6 hours (without us mining), they've managed to find all of 9 blocks.
It's a catch-22. When we're not mining, it takes all day to confirm our coins. When we are mining, profits are good but we're killing the coin. They're talking about a hard fork in the near future to correct the abnormally long diff re-targeting.
Catcoin experienced the same thing, for the same reason. There are a number of coins being created now by folks who do not understnad the dynamics of alt-coin mining and thus their coins suffer the same fate. Stablecoin was also forced to make that hard fork as well.