Batboard

I have recently acquired a couple of astro spectra plus 800 MHz radios and have a question. One model number is: D04UJF9SW5AN and the other is: D04UJF9SW5BN. I know the A version has the 4-meg VOCON and the BN has the 8-meg version. Are there any other differences and what does the 8-meg give you as far as a real difference over the 4-meg? Thanks for info in advance. Flash on both is: 580008-001684-4

ASTRO Spectra Plus radios which model numbers end with ‘AN’ can only be upgraded to version R09.00.41 for the host, R16.00.01 for the DSP, and R05.07.15 for the UCM (if applicable). ASTRO Spectra Plus radios which model numbers end with ‘BN’ can be upgraded to version R20.00.01 for the host, R19.50.00 for the DSP, and R05.07.15 for the UCM.

implies the amount of memory on the processor board like the XTS2500A/B