HP 32SII speed differences

[Dave Britten]

I have both an older 32SII (3116A, 1991, ROM 0) and a newer one (ID108, 2001, ROM 1, the green/purple/silver design). For kicks, I ran the n-queens benchmark on both of them to see if any subtle manufacturing differences would have them finish a couple of seconds apart. I certainly wasn't expecting this stark of a difference.

The older ROM 0 model finished in 00:05:03, much faster than reported for the 32SII on the benchmark page. The newer ROM 1 model finished in 00:05:45, which is just about on the nose with the list of results. When both of them are running the program, the "PRGM" indicator on the older one flashes visibly faster than on the newer one.

Can anybody else reproduce similar results with the two different versions? I'm wondering if it's due to the ROM version, or some other hardware difference. Does battery voltage affect speed to this degree?