need input on nightforce ballistics software/dell axim setup

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I'm looking to pull the trigger on the NF ballistics software. I have 2 old dell axims(a x-3 and an x50) that I was going to install the software onto. The software comes in a cd -rom(download onto axim from your computer) or an sd type card(insert into axim). Does anyone use either of these systems on their axims? Looking for some feed back on whether I should go with the cd or sd card?? Any input is appreciated..