Greg summed it up well. All I would add is that it's probably a good idea to buy a recognized 'name brand' CF card, just because the better known manufacturers have a reputation to protect. The implication is that the quality control practices of a name brand manufacturer are likely more stringent, so the chances of getting a defective card are much lower.
There are (more or less) three different industry speed levels of cards, and the choice of speed level for any application depends on how often data needs to be written to the card, and how frequently data needs to be read from the card.
For use in a SP 26xx, we want the slowest speed card, which is one that is designed to be written to only rarely (meaning, it doesn't matter to us how long it takes to write to it), and read from only occasionally.
The time it takes to load maps into a 'low speed' card will be longer than the time it takes to load a high speed card that costs twice as much. But, you can load a low speed card using a CF card PCMCIA adapter (a ₤10 purchase) in half the time it takes to load the fastest and most expensive CF card using the USB cable - so do the math. I posted a detailed blurb about CF card PCMCIA adapters at
this thread.
So far as reading data from the card is concerned, the GPSR itself won't work any faster with the most expensive (fastest spec) CF card than it will with the least expensive (utility grade) CF card. Maybe you might save a tenth to a quarter of a second at boot-up with the most expensive and highest speed card. That's all. There will be no further difference at all once the GPSR is up and running.
The faster speed CF cards (anything faster than utility grade) are intended for use in digital cameras and handheld PDAs, where any kind of delay writing to the card is a nuisance and needs to be minimized. This is not a concern for us at all, our GPSR's never write to the CF cards.
PanEuropean
