1Dx: what's the "right" CF card?

[Kayaker72]

My understanding is that the 1DX is compatible with UDMA 7, which, in theory, allows for transfer of up to 167 MB/sec. The minimum you want, for video at least, is 10 MB/sec for IPB compression or 30 MB/sec for ALL-I. So, in theory, the 1DX should be able to see the full benefit from the new Lexar "1000x" (150 MB/sec) or Sandisk 160 MB/sec cards. I say in theory, as actual transfer rate could be limited and "compatible" just means that it accepts them. BTW, I found a thread where someone claims to have used a Lexar 1000x card and got 30 RAW files before the buffer in the 5DIII filled and the fps slowed. That beat what I get with my Sandisk Extreme Pro 90 MB/sec UDMA 6 card where the buffer fills at 12-13 shots.

BTW, apparently Sandisk has been selling UDMA 7 cards from 90 MB/sec up to 150 MB/sec. Seems the higher the memory capacity the faster the transfer rate with the 150 MB/sec in the 256 GB cards. So, not all UDMA 7 cards are going to give you 167 MB/sec.