Then IBM also built the hybrid electronic-electromechanical IBM SSEC computer (operational from January 1948), which was a truly general-purpose digital computer, which was available before any fully-electronic computer and for a few years it was the most powerful computer of the world and it solved many important problems.

While ENIAC, being completely electronic, remained faster than SSEC for a few problems, most problems could not be solved at all on ENIAC, because it had no big-capacity memory, so for most computing problems SSEC was the best choice until the completion of the first electronic computers with memories based either on cathode-ray tubes or on delay lines or on magnetic drums.

IBM SSEC was available as a public computing service, so it was used by many companies and institutions. Besides SSEC, before the first electronic computers there were a few others electromechanical computers, e.g. at Bell Labs or at Harvard, but those were slower and had fewer users.