You don't need snowblossom-3 anymore, you need .6 now and .7 soon. And yes, the .11 is 2TB, every snowfield is twice the size of the previous one. This is the GPU/ASIC poison-pill: even if someone builds a miner for 128GB files, it will have a hard time once the 256GB snowfield is activated and most likely will be useless at 512GB and higher.
As far as I understand snowblossom, it uses those huge files via memory mapped IO if available on the OS, so it can do random-access operations on 4K blocks in those snowfields as input to its PoW. A general-purpose CPU with a lot of RAM and many threads would have a much higher throughput and therefore lower latency compared to an usual ASIC.