| Manufacturer | Model | Write | Read | Label |
| SanDisk | Standard (no speed rating) | 4.5MB\Sec (30x) | 4.5MB\Sec (30x) | None |
| Ultra II | 9MB\Sec (60x) | 10MB\Sec (66x) | 66x | |
| Extreme Ducati | 20MB\Sec (133x) | 20MB\Sec (133x) | 133x | |
| Extreme III | 20MB\Sec (133x) | 20MB\Sec (133x) | 133x | |
| Kingston | Secure Digital | |||
| Secure Digital Elite Pro | 7.7MB\Sec (51x) | 8.2MB\Sec (55x) | 50x | |
| Secure Digital Ultimate | 20MB\Sec (133x) | 21MB\Sec (140) | 133x | |
| Secure Digital Class 2 | 2MB\Sec (13x) | 2MB\Sec (13x) | Class 2 | |
| Secure Digital Class 4 | 4MB\Sec (26x) | 4MB\Sec (26x) | Class 4 | |
| Secure Digital Class 6 | 6MB\Sec (40x) | 6MB\Sec (40x) | Class 6 | |
| Crucial | Secure Digital | 3MB\Sec (20x) | 3MB\Sec (20x) | None |
| Lexar | Platinum II | 8.5Mb\Sec (57x) | 8.5Mb\Sec (57x) | None |
I completely believe all the manufacturers got together (except SanDisk I have to say) one day in a room and came up with the most opaque, random and damn right hard to fathom system of classifying the speed of their cards. Possibly it took them a week.
Basically I think all you need to know about a memory card is how big it is, that’s easy peasy and then how fast it is. To find out how fast it is you need a standard of course and you also need to be measuring the same thing each time. There is a standard out there (1.5MB\Sec = 1x) but not everyone uses that, and then there are two really important things to measure that matter the user, read and write speed. But then there are other measures too, erase speed and of course you can average these (or choose to just average two of them etc etc!) Basically trying to compare memory cards from the info you are given is almost impossible. Some manufactures don’t even display any speed info about their products or hide it way away in techno babble in some distant document.
Does speed matter that much? Possibly not if you’re just snapping away with a compact camera so I’d stop reading right here - (a bit late sorry!) there are better things to be doing right now. It would definitely matter on professional digital SLRs but could also definitely matter on your more standard DSLR like I have or the new compacts capable of recording HD TV video. What I was more interested in though was just getting the best card for the money, going off a big trip like this one, it’s going to be a real arse if I get somewhere and I’ve either run out of cards because I bought too few because they were too expensive or bought the cheapest biggest cards and missed that amaaazing shot because the camera couldn’t write the last picture fast enough. Second thoughts, I don’t think I’m going to take a camera now. You can spend too much time looking through a lens.
Sources and more info:
http://www.valuemedia.co.uk/sd_card_speed_tests.htm
http://www.sandisk.com
http://www.kingston.com/flash/photo.asp
http://www.trustedreviews.com/storage/review/2006/07/22/Memory-Card-Roundup/p5
http://www.trustedreviews.com/storage/review/2006/07/22/Memory-Card-Roundup/p7
http://club.cdfreaks.com/f122/sd-cards-speed-ratings-card-readers-writers-199888/
