Hi Andy:
I don't know the answer to that question. I am going to take a guess (I emphasize that this is a guess only) that the two GPSRs could probably store the same number of custom POIs, assuming that all other factors are equal - for example, the size of the memory installed in the GPSR, and the size of the cartography file stored in the GPSR.
My understanding is that Custom POIs are stored on the same physical memory as the cartography (and the music files, if you have a 2820), therefore, if you have installed additional cartography beyond what came pre-installed from the factory, or if you have installed MP3s, that will encroach on the space available for Custom POIs.
FYI, I have installed files containing about 12,500 Custom POIs on both a 2720 and a 2820, in each case the GPSR had the full set of City Navigator Europe version 8 maps installed. There appeared to be about half a gigabyte of memory still free on the 2820 for music files, so, I don't think we are going to encounter any problems with Custom POI file size limitations in the near future (next year or two). The Custom POI database I use covers all of Europe, although it doesn't have comprehensive coverage of the UK. I suppose that eventually, as the size of the cartographic database continues to grow and the size of the commercially available Custom POI databases continues to grow, we might hit the limit of physical memory capacity, but when that happens, we can then start thinking about workarounds - for example, deleting map segments from the GPSR that we never ever expect to use (how many folks really need the detailed street maps of Athens and Helsinki that are pre-installed on your GPSR?).
Michael
