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HP 50g & SD Cards: Performance, Format, Notes
07-20-2016, 04:53 PM (This post was last modified: 07-20-2016 04:56 PM by Joe Horn.)
Post: #24
RE: HP 50g & SD Cards: Performance, Format, Notes
(07-18-2016 04:33 AM)JDW Wrote:  Joe,

If your Pretec SD card marked "60X" performs a backup of 200kb in 1.5 seconds, then please use a slower card (say an old 128MB or so that runs at 2MB/s) to perform the same backup and then tell us how fast it copies. If a 2MB/s card backs up 200kb in 1.5 seconds just like a 15MB/s card, then such confirms there is truly no meaning to use a faster card. And such will also tell us that it would be prudent to use something smaller than 1GB for the sake of smaller and fewer clusters, to further boost card performance.

Good idea... so here it is. The following table supports my claim that card speed DOES matter, HUGELY in fact... but so does the FAT format. FAT32 and/or a slow card will dramatically slow down power-up and storing especially of large objects like backups. As you can see, the CAPACITY of the card doesn't seem to matter much, if at all.

Sorry about the format ambiguity; all I know for sure is that Win7 says that these cards are formatted as "FAT". I'm guessing that means FAT16?

Testing the differences between a nearly-empty card and a nearly-full card, and testing the 50g's speed of reading different cards, is left as an exercise for the reader.

EDIT: My earlier claim of 200K backup in 1.5 seconds was mistaken. It was a 40K backup, not a 200K backup. It's the second card in the table below.

[Image: SD-cards.jpg]

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RE: HP 50g & SD Cards: Performance, Format, Notes - Joe Horn - 07-20-2016 04:53 PM

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