Originally posted by Vaikis_ what SD cards you use for measurments ? Please use LexarŽ Professional 133x - it's very fast card
I was using a SanDisk Extreme III., so I don't think speed was the issue.
I also agree with the other posters that suggested this is not really a card speed issue but more of a processing bottle neck. I notice it just shooting single high-iso shots when it takes 1-2 seconds for the preview on the rear LCD to show up.
One other thing to keep in mind is that the size of the RAW files, for the same shot content, varies quite a bit. For the test image I shot (the one with the toy dragon, car and medicine bottle), the RAW file size was as follows:
K5__0991_iso100.DNG 18.41 MB
K5__0992_iso200.DNG 19.68 MB
K5__0993_iso400.DNG 21.44 MB
K5__0994_iso800.DNG 23.14 MB
K5__0995_iso1600.DNG 25.40 MB
K5__0996_iso3200.DNG 26.44 MB
K5__0997_iso6400.DNG 28.96 MB
K5__0998_iso12800.DNG 31.63 MB
K5__0999_iso25600.DNG 32.70 MB
K5__1000_iso51200.DNG 32.71 MB
So I'm sure this is also a large factor in how many shots can be taken before the buffer fills.