But.. wouldn't that defeat the purpose of YAC, aka being mined only with CPUs?
Well, right now GPU is almost 16x faster than a CPU mining YAC... So if someone decided to launch a 51% attack on YAC network, he would need approx. 103 GPUs (which is not that much if you consider GPU farms used to mine LTC). Also, GPU mining could stop working on August 13
th, but I would not count on that (IMHO it would become impossible in mid-2015 with *current* GPUs, considering the scratchpad size of 32M [at least on my GPU, considering I'm not completely wrong, which I might be

]).
Hmm, you're right.
In my opinion (keep in mind that I'm pretty noob at this stuff), the developers should try to focus on making the coin mineable only with CPUs.
This way we won't need a GPU miner to prevent 51% attacks.
But I have no idea if it's possible to make it safe from GPUs.