UDMA Enabled Flash Cards

There should be zero difference in picture quality (in this case, bits really are just bits), and having CRC is a big advantage. A clock signals goes up, then down, up, down... Standard transfers happen once per clock cycle, using just one edge of the clock. UDMA (and DDR memory) use both edges, transferring twice as much data per clock cycle (period). This requires greater bandwidth circuits as capture happen twic as fast (in half the time). Error correction (CRC) helps maintain data integrity despite the higher rates.

I don't have any (getting a good DSLR got put off for a while) but have friends who like them a lot. Don't know about SDHC versions, but they should work fine. Get good ones, not generic (I have had, and heard, of many problems with the copies) from B&H or whomever.

I wil say that I am not sure there's any real benefit with an S95 except when you download the pix to your PC. The faster cards mainly benefit cameras with lots of pixels and high burst rates.

I wouldn't worry about the lingo that manufacturers use to describe how they get higher performance. UDMA was a technique uses a while back so it is no longer an innovation.

What matters is the exact throughput you get in your camera and in your PC. These are different things as cameras are usually a generation or two behind the card capability.

Fortunately, there is a great resource to get this data: http://www.robgalbraith.com/bins/multi_page.asp?cid=6007

Rob benchmarks many cameras and cards against each other and posts the data int he above database. It is focused on DSLR cameras though as those are the people who usually care and need the speed. A P&S camera doesn't usually have the frame rate to require the highest performance. Still, if you buy a card which has high performance with DSLRs, then it is likely to be a fast card regardless of where you plug it in.

He also benchmarks flash card readers.

Only hitch is that he has been slower to update his database than when he started.

OT: Amir -- Can USB actually do DMA? Is that just in the camera? I am not sure the USB protocol and if the drivers have DMA (I am asking because I do not know, something I have not looked up).

Curious - Don

I have not had to write a driver for USB so don't have first hand experience. That said, whether a device supports DMA is a function of the host interface and in the last 10+ years, it has become trivial to provide DMA support in these controllers.

Makes sense, thanks. - Don