And no, the slower miners don't see any negative impact, because we accept shares, and pay them for shares for (CurrentBlock) and (CurrentBlock - 1). If a block is solved every 600 seconds, it would take them 1200 seconds to have their new shares for a getwork become stale.
So if i understand correctly, slow miners will be subsidised from money of honest GPU users ?
Just asking.
Your question also imply's that the CPU miner's are using a higher askrate, which at the time of writing this the CPU miner's appear to be using a askrate of 10 or less, so no.
But, if they were to use a higher askrate (say 600 seconds), then yes, their profits would be subsidised from the GPUs.
We've done this to accommodate them while we work on the CPU pool. We're hoping to have it up and going in the next few weeks.
When we launch that pool, we'll be back down to CurrentBlock submissions only.