To lower cost, the system used a bit-serial arithmetic logic unit (ALU) and was thus significantly slower than contemporary designs which had parallel ALUs like the Intel 8080 or MOS 6502. Another oddity was that the program counter could only access the lower 12-bits of the 16-bit address, and the upper 4-bits had to be set using special instructions. The result was that instructions accessed main memory as sixteen 4 kB "pages". The combination of slow speed and paged memory limited its attractiveness, especially in the markets that might need a multiprocessing system.