Sun 04-Aug-13 08:38 PM | edited Sun 04-Aug-13 08:41 PM by mirek21
>I know we can't get to the total bottom of the card issue, as >we don't have the real design details, (I checked, we could >all collectively pool $5k and get some reverse engineering >documentation on Expeed from chipworks).
We don't have to. I think it is very likely that you are right and the SDIO signalling speed is indeed 100 MHz and thus the D600 can't write more than 50 MB/s over the SDIO interface.
However, what we can do it to measure how these 90/95 MB rated cards perform in the D600, just as I did. My finding is that the 600x (90mb/s) card clearly perform better than top 45 MB card in terms of speed of cleaning up the buffer. And that translates to number of frames captured in a long burst.
I am not claiming that the D600 can fully utilise these speed of 90MB/s cards. I am just saying, that 600x+ cards still offer a solid improvement over 400x cards and it could make a sense to buy them even for the D600.
BTW. I've just find that my results are more or less confirmed by Rob Galbraight (although on D800 and he uses a slightly different method). He measured ~30 MB/s on 45 MB/s rated card and 40 MB/s on 90 MB/s card. I doubt that the D800 has UHS104 (208 MHz) or UHS-II SD interface...