It's a GTX 670. has 1344 cuda cores. 1344x32 works at -L 512. No matter what I specify for -L, doubling doesn't work. Out of memory every time.
but can't you just ignore the out of memory? it's for scrypt related buffers mostly, which keccak doesn't need.
maybe -L 1024 -m 1 does the trick?
Nope, it actually crashes. It starts putting out crazy hashrates, but if you check the GPU load you can see it actually gave up and isn't doing anything.