I have always owned a ton of memory cards. Years ago, in the dawn of digital, I lost a morning of shots that I thought had been properly backed up to a Digital Wallet, and blithely formatted the cards I had and kept shooting. I ended up reshooting three or four shots, a half day, at my own expense with four models and crew because the Digital Wallet (actual brand) died in the middle of backing up a then whopping 340MB, and I didn't know it. As a result, fast forward a little and I owned a couple dozen CF cards and used them (as I still do now) like individual rolls of film (though I shoot one shot to a card so it might be 150 frames or 500 frames). One shot, one card. My philosophy has always been to have enough cards to do two days of a catalog and never reformat a card (though everything is backed up throughout the day). Sadly, my CF cards sit in a bin without a camera in which to use them. I now have a couple dozen SD cards. Not unlike my CF cards, their read/write speeds seem to vary a lot based on manufacturer. All though are "film roll sized" 32GB.
I own a Canon R5 and thought I might as well dip my toe into CFExpress since that seems to be a coming standard. However, they are bloody expensive averaging about $99/64GB card. At that price, I hate the thought of getting a lemon in terms of performance. I bought three cards, all costing $99 from B&H: Lexar Pro 64GB, SanDisk Extreme 64GB, and the Delkin Prime 64GB. The real gem was the Lexar as it was being sold bundled with a Lexar USB3.1 Gen2 CFExpress reader. My following tests were all done using this reader in one of my Gen2 USB-C ports. To make things interesting, I decided to "build" my own CFExpress card after reading articles in PetaPixel and Tom's Hardware. It seems the CFExpress cards are really just small NVMe 2230 SSD drives stuck in a housing. I bought a Sintech housing direct from the company for about $47and a Kioxia (formerly Toshiba) 128GB SSD from Amazon for $15. So, for a neat $62 and about 15 minutes of my time, I had a card with twice the capacity for about 1/3 less money. But would it perform?
See my tests and bar chart for yourself. In short, my DIY was a good buy. The other take away is that SanDisk is not the performance company it once was. While the other three were similar in write performance, SanDisk was severely lacking.
