Theoretical maximum speed of today's popular MMC 3.x and SD 1.0 cards are 2.5MB/s (16X) and 12.5MB/s (83X) in SD's favor, however, theoretical maximum speed of advanced specifications call for much higher speed of MMC 4.x at 52MB/s (346X) vs. SD 1.1 at 25MB/s (166X). Pretec 4GB MMC Plus 266X, with access speed up to 40MB/s, doubling the speed of recently announced Pretec 4GB SD card 133X, is the fastest small form factor flash memory card of any format in the world. Pretec 4GB MMC Plus is available now for key customer sampling with unit price of $699 each, mass production is scheduled by Q4 of this year.
Maximum capacity of SD card is 4GB under v.1.1 spec. and is also 4GB for MMC under v.4.1 spec. using so called "Byte Addressing" scheme if the file format of FAT32 is adopted. Pretec 4GB MMC Plus can be configured to be fully compliant with MMC 4.1 specification under traditional "Byte Addressing"; or alternatively Pretec 4GB MMC Plus can be configured under "Sector Addressing" scheme pioneered last year by Mu-Card Alliance in which Pretec is a founding and major contribution member. Maximum capacity of Mu-Card is 2TB (2048GB), which can potentially soon become the maximum capacity of future specification of MMC card. Mu-card Alliance and MMCA has announced the joined forces in June 2005.