SD performance starting to drag as card fills

Got an issue I haven't seen (or noticed) before on an SD or CF card, got a brand new EOS6D and a brand new SanDisk Ultra 64GB SD-XC card (30 MB/s).

Everything starts fine but as the card approached around a 1/3rd full I noticed delays in write speed, particularly evident with how long it took for the LCD screen to display the image just taken.

Not 100% convinced its the card as I am not sure if the image just taken is reliant on the card to display on the LCD.

Has anyone seen this or something similar?

why do feel using a 64 GB SD is better then say 8 or even 16 GB sdhd ! some where i herd that the larger SD-XC take longer to right in camera! you could try using a smaller card and see if its doing the same thing.

blanex1@netzero.com wrote in post #17001885
why do feel using a 64 GB SD is better then say 8 or even 16 GB sdhd ! some where i herd that the larger SD-XC take longer to right in camera! you could try using a smaller card and see if its doing the same thing.

I seem to remember a discussion a while back in regards to the merits of fewer larger cards vs more smaller cards. I buy on GB/$ sweet spot, and that it so happened that 64GB was it in that level of performance. I have some slower 32GB SD-HC cards already, I might try those.

At the end of the day I decided quite some time ago that one card in the camera when out and about was the lowest risk for me, yes I could loose everything if something happened, but with more cards I am more likely to loose one but wouldn't be everything.