5D MK IV, memory card for 4k

[hovland]

Hello
got my MK IV, a week ago, and my initial conclusion about the camera is great.
But I discovered that the 4k video recordings did have a sound glitch/hang every 5 seconds. I have a Lexar 128gb 1000x CF card. And I was I but surprised that this card was not up to the task. Tried to completely format the card several times and on my computer. Did a write test disk mark and the cards have a max write speed of 110mb/s.
Is there any hoe ore do I just have to get a new 1066x CF card

 

[Helevitia]

Although your card is UDMA 7, it has a minimum write speed of 20MB/s (look at the picture on the bottom right). The 1066x card has a minimum write of 65MB/s. So yes, your card seems to be too slow. I think the minimum should be 30MB/s.

Keep in mind the same problem exists for the SD card as well. You need a UHS-1 Class 10 - UHS Class 3. The UHS Class 3 is the important part. It means it has a minimum write speed of 30MB/s vs. UHS Class 1 which only has 20MB/s

 

[hovland]

Although your card is UDMA 7, it has a minimum write speed of 20MB/s (look at the picture on the bottom right). The 1066x card has a minimum write of 65MB/s. So yes, your card seems to be too slow. I think the minimum should be 30MB/s.

Keep in mind the same problem exists for the SD card as well. You need a UHS-1 Class 10 - UHS Class 3. The UHS Class 3 is the important part. It means it has a minimum write speed of 30MB/s vs. UHS Class 1 which only has 20MB/s

Thanks
Have ordered a new Lexar CF 1066x.
Did try a SanDisk Extreme PRO SD UHS-II, but in UHS-I mode its slower than some native UHS-I cards. Only got 4-5 sec of 4k video before auto stop. (only shoot Jpeg, as a backup on the SD card)

 

[xps]

Took some first 4k videos before returning for GPS repair. Filming my great-grandchildren was a pleasure.

SanDisk Extreme PRO SDXC 64GB UHS-II card worked well, the SanDisk Extreme PRO SDXC 64GB UHS-I/Class 10 stopped recording after 2-3 minutes. Do not know, why the UHS II Did not stop.
No problems with SanDisk CF Extreme PRO 64GB 160MB/s.
The Lexar CF Professional UDMA 1066x 64GB from my 7DII worked fine, there was one stop in videorecording after some minutes.