I haven't looked into this too closely, but all/most of the recent blocks awarded to ASICMINER have a much lower transaction count than those awarded to other miners/pools. Is that a coincidence, is it a consequence of the hardware design, is it somehow indicative of the recent drop in hashrate?
Coincidence. I saw one earlier with 600+ transactions.
Regardless, there is no mechanism in BTC to selectively mine blocks. I.e., you can't mine a 100 transaction block more easily than you can mine a 1,000 transaction block with a given difficulty. This cannot be done by adjusting hashrate either. At a given difficulty, your probability for mining a block is fixed to a certain hashrate over a period of time. A lower hashrate will have a lower probability, and a higher hashrate will have a higher probability.
In short, hashrate and difficulty have nothing to do with the size of the block you mine.
Ian
Hashrate and difficulty are unrelated to number of transactions, but a poorly connected node may show low number of transactions - which may also be a problem when broadcasting blocks! I.e. if two miners find a block almost at the same time, the well-connected node wins the block because it is broadcast more widely.
Not saying that's the case, but a low transaction number could be a signal of a poorly connected node, which could be a disadvantage in a race.
So... the drop in effective hashrate could actually be the result of a DDOS on the ASICMINER node(s)?
It did conveniently stop after the dividend payout - it could be someone trying to manipulate the price, or one of the other pool operators.