DEVELOPMENT SYSTEMS with AMD's upcoming 64 bit CPU are percolating quietly out into the Linux world with various top hackers dropping hints here and there that they have real hardware in their programming caves.
All the geek world wants to know the performance of Clawhammer, the plucky (some would say foolhardy) little junior of the 64 bit computing world or Testopteron, the beefy 'medium tin' offering, but it seems AMD has slapped heavy NDA agreements on those otherwise freedom-loving wild frontier Linux-programmers.
However, little snippets do leak out. It seems that Hammer is "a few percent faster" on most tests in 64 bit mode than it is in 32 bit mode. Unfortunately, there are two or three of the SPECcpu tests that slow down 50%. It's not hard to guess why this could happen: In 64 bit mode data pointers are twice as large, and if your program handles a lot of those pesky little intra-memory cross-references, it's going to be accessing a lot more memory.