Have been testing DRK mining at coinotron for a while now with release34, and the pool is underreporting hashrate. Haven't tested previous releases there in detail. Unfortunately, coinotron does not draw nice graphs AFAIK, but the hashrate reported is always an average of the last 60 minutes, so it should be quite accurate. I checked several time today and it was always reported between 14.7 and 15.2 MH, while it should be at around 17.5 MH according to the miner.