Bringing Atari Up To Speed

I am quite confused and disappointed. I have written several games on my Atari 800 (purchased in October 1981) and given them to my brother to run on his 400 (purchased in May 1982). These programs (which include machine language subroutines and player/missile graphics) invariably run much faster on the newer machine. I suspect it is because of the "upgraded" operating system that supposedly came out in December 1981. But every attempt I have made (with repair centers and dealers) to get the new OS ROM for my machine has failed. What can I do to bring my system up to speed?

Edward Loniewski

The speed upgrade could be due to a lesser amount of memory. A machine with 16K runs a little faster than the same machine with 48K. This is due to the use of "dynamic" RAM memory. Dynamic RAM is less expensive than "static" RAM, but it must be periodically refreshed by an electronic signal. During refresh, the 6502 is not allowed to access memory. Since 48K of memory takes longer to refresh than 16K, there is some difference in speed, but it wouldn't be drastic. Another possibility is that your brother has an Atari 400 with the new, Revision B 10K ROM, which may be faster than Revision A since the interrupt routines were streamlined. Benchmarks anyone?