5DM3 : What speed SD card is optimal

Knowing the 5D3 SD performance is not as good, what is the optimal SD card one should use (just for the backup or emergency purpose).
I believe the Extreme III type of speed is a waste..
So at what speed 5D3 will max out on the SD interface..

imho:

SD/CF card prices have become more and more affordable over the years. SD read/write speeds have come a long way as well.

I'd opt for the fastest & best reviewed SD card you can get. Reason for me, it will be the best/fastest SD card now & will be great later for future applications.

I now stick with SanDisk SDHC Memory Card Extreme Pro Class 10 UHS-I 95/90 MB/s. Most of the time its the 16gb offering.

I can't remember the speed on top of my head, but SanDisk extreme is more than enough, so no need to go extreme pro.

I think it maxed out at 40mb/s.

In the 5DIII the fastest CF cards will write @ 80.2MB/s

The fastest SD card will only write @ 19.9MB/s ie: 1/4 speed.

This is what the OP is referring to when asking.

-The Sandisk Extreme Pro 95 only gets 19.4MB/s

-Where as the slower "normal" Extreme manages 19.3MB/s ( see a difference? not really )

- And a lowly Transcend UHS-1 18MB/s


So no, don't waste your money on the fastest SD card for a 5D III


-Dropping down to an old school Sandisk Ultra gets 15.5MB/s

Although 5D3 supports super fast UDM7 CF cards, it failed to do the same to its SD architecture. Therefore there's a bottleneck by using SD cards. I suspect it was put there to support video shooters who really do not need fastest card speeds.

http://jeffcable.blogs​pot.com …-put-sd-card-in-your.html

CyberDyneSystems wrote in post #16012380
In the 5DIII the fastest CF cards in that camera will write @ 80.2MB/s

The fastest SD card will only write @ 19.9MB/s ie: 1/4 speed.

This is what the OP is referring to when asking.

-The Sandisk Extreme Pro 95 only gets 19.4MB/s

-Where as the slower "normal" Extreme manages 19.3MB/s ( see a difference? not really )

- And a lowly Transcend UHS-1 18MB/s

So no, don't waste your money on the fastest SD card for a 5D III

My point exactly.
I am looking for a card that would be best (and not fastest in the world) for 5D3 that can work as a backup or emergency only.
So I guess cards around 18-20 MB/s write look to be optimal.