Testing your builds
enable this disabled line in maxcoin.cpp (be sure to take it out again before actual mining)
// TESTING ONLY
((uint32_t*)ptarget)[7] = 0x0000000f;
run cudaminer with the --debug (-D) option and watch if you get this:
[2014-02-06 15:57:01] DEBUG: hash <= target
Hash: 0000000d72a9d97d68d1e2ddb20809b4ad4623b895f0dfde715cd82b4e54d606
Target: 0000000f00000000000000000000000000000000000000000000000000000000
if you get the dreaded "does not validate on CPU" errors then your launch config or even your
build is having a problem.
This should help you figuring out if your 450 MHash/s are real or not.
EDIT: kHash/s -> MHash/s