
02/20/2007, 03:34 AM
#198
I haven't bought one of these 8GB SD cards yet, but according to the standards, the SDHC cards ARE really slower. There are three classes of SDHC (or SD 2.0):
* Class 2: 2MB/s
* Class 4: 4MB/s
* Class 6: 6MB/s
On the other hand, normal SD cards (SD 1.0) which are smaller than 2 GB (with some nonstandardcompliant 4GB available) max out at a much higher speed. When you see an SD card says 150X( or 80X) it means it is 150 times (or 80 times) faster than a standard CDROM device (150 KB/s). Some common speeds are:
* 8X = 1.2 MB/sec
* 12X = 1.8 MB/sec
* 20X = 3.0 MB/sec
* 25X = 3.8 MB/sec
* 30X = 4.5 MB/sec
* 40X = 6.0 MB/sec
* 45X = 6.75 MB/sec
* 60X = 9.0 MB/sec
* 66X (SD 1.01) = 10.0 MB/sec
* 80X = 12.0 MB/sec
* 90X = 15.0 MB/sec
* 133X (SD 1.1) = 20.0 MB/sec
* 150X (SanDisk Extreme III SD) = 22.5 MB/sec (minimum 20MB/s guaranteed)
Note that by a quick search in newegg you'll find out that the cheapest 2 GB SD cards have 45X to 60X speed, 34 times faster than the class 2 SDHC cards.
Now The speeds are improving, e.g. SanDisk UltraŽ II SDHC 4GB runs at 10MB/s, but it retails for $220. The normal SanDisk Standard SDHC™ Card 4GB which retails for $120 is a class 2 device though.
So, You can decide whether it's worth it or not. You are looking at a 5 times slower speed. In my opinion it would be fine for mp3 and picture browsing, and perhaps watching video (although video takes much more bandwidth, and I guess you may experience choppy scenes sometimes, expecially on action scences where there are a lot of fast changing frames and the bandwidth requirement increases significantly).


