To answer my own question:
1) Set mpurate in u-boot, or
2) Use the cpufreq tools in linux.
Apparently Sakoman's u-boot limits the CPU freq to something lower than the max rate of my Overo Fire.
From: Greg Kogut <email@example.com>
General mailing list for gumstix users. <firstname.lastname@example.org>
Sent: Tuesday, March 13, 2012 12:01 PM
Subject: setting Overo CPU speed
I recently swapped my gumstix OS from a custom OE/Anstrom OS running off uSD to the latest sakoman console image running off nand.
I noticed a large performance drop with the sakoman image (with identical binaries). It's not disk-related - my program performs no disk IO.
cat /proc/cpuinfo was identical except the sakoman image reported lower BogoMIPS for the
sakoman console image. Here is the
BogoMIPS : 719.47
BogoMIPS : 497.82
Any ideas what's going on here, and how to resolve? (google wasn't a big help initially).