From what I understand, the difficulty of most chess engines is determined by how long they are allowed to 'think' about the moves. From what I understand, the performance of software based chess applications has increased massively over the years, but I'm not sure if hardware limited engines have increased performance in a similar fashion.
The reason I ask is because my father owns a fairly old electronic chess set, but finds that the advanced levels take too long to compute their moves. I'm wondering if I buy a more modern board, can I assume that a similar level of difficulty can be achieved with less waiting time? For specifics, he already owns a systema Jupiter board, and I'm currently thinking about the Lexibook chessman elite, which is on the cheaper side of things.
Apologies if this doesn't fit the site's remit, it seems an appropriate place to ask.