The US's PC Magazine Labs got an early peek when Hewlett-Packard accidentally sent in a system housing a 200MHz MMX chip for a group review. At first the unit was not discovered as an MMX, thanks to the CPU being covered deep in the system's bowels. According to the PC Magazine tests, the P55C can add about 10 per cent in performance to today's Windows 95 applications compared to a standard Pentium running at the same clock frequency.
However, tests with one MMX-enabled application suggested that the CPU's 32Kb L1 cache - double the size of that in a standard Pentium - was a significant part of the reason. PC Magazine said an Intel spokesman agreed with the finding that the chip will offer about a 15-20 per cent performance hike for MMX-optimised apps.
"It was inadvertent on HP's part," said an Intel UK spokeswoman. "System makers continue to be under non-disclosure agreement [but] people make mistakes."
Intel has said that it sees MMX as a milestone in the X86 architecture but if the PC Magazine findings are replicated in shipping systems, users will be disappointed. Intel will introduce MMX across all its processors and both Cyrix and AMD say they will use the same or similar algorithms.
Two UK PC vendors contacted by PCDN said they expected to be able to ship MMX systems in December although volumes of the chip aren't expected until the new year.