edit: In the subject you mean "+400 MH/s mining ltc" I think.With a hash rate that high I wonder why anyone would bother using a pool.
Hypothesis:
- It's a former Bitcoin GPU miner with more than 500 7970s.
- Someone figured out how to mine LTC effectively with an FPGA or ASIC.
- It's a botnet.
I'd guess botnet. Especially so since the hash rate fluctuates throughout the day. It's only about 294MH/s now.