I think the original poster was mistaken. If all the RAM chips are present on the A2630 then you have 4MB. If there are empty spots for more chips then you probably have 2MB and that is why it would show 4MB of fast RAM (2MB on A2630 and 2MB on A2091).
Running bustest is one way to identify which RAM is on the A2630 since it will be much faster.
