speedstep cpu with AC off is running too high 850->700

[BeemerBiker]

I am seeing an 850mhz drop to 700mhz instead of the 500 shown here http://www.bay-wolf.com/speedstep.htm
Can I assume that IBM limited the drop in speed to 700 instead of 500? I assume I have the low voltage and not the ultralow voltage package. I have 2628-4TU with 850 speed cpu. Both CrystalCpu and "Intel Frequency ID Utility" verified the the 700mhz. AFAICT the cmos was set up correctly with "automatic" selected for speedstep. I thought speedstep even on these older A20M would increase/decrease linearly with cpu utilization. I must be wrong or have wrong setup????

..thanks..