the problem is, you're stealing from the other who mine in the pool as you're share rate is displays higher than it really this thus giving you more from the block than you deserve.
good pool ops see this immediately and ban you from the pool (freezing your earnings until then) and fix their pool soft so nobody can do this again.
I know what he's done, then. Changed the algo from scrypt, right? You can submit invalid shares very quickly by using a different algo.
If what you're saying is true, this merely takes advantage of a fault in some versions of existing software, and doesn't improve the hashrate of the physical hardware the way the OP implied it was.
guess where the currency comes from to fill this guy's wallet? From the other pool miners who paid hard earned money for their hardware.
If op is just showing off a software hack, he is a parasite telling us he's getting a free meal.
Just think over it..
There is no way of "tweaking" a 5770 to a 7970 :-)
Its simply an "exploit"..
It was used before on many, many pools, many people tried in on my pool too weeks ago.
The OP is just the first one who posted about it on bitcointalk.org
There is a issue ticket @ the stratum software from me already some time ago.
Maybe its good, so the other pool ops are forced to update their software.