I got myself some SDcards and decided to measure how they perform with writes using an OM-1 camera and reading out of a macbook laptop. The camera has a 90 frames buffer, and supports SDXC and UHS-2 cards (see the types of SD Cards). I set it in high speed shooting and monitored the noise of the snapshots.
The read performance is limited by the MacBook, so I will try again with a fast modern desktop. The test was to copy 100 photos generated by the write test, or about 3.3GB. A USB-2 port has a max I/O performance of 480Mbps or 60MB/s, and the cards were able to deliver it.
The write performance varies by cards. Some have even throughput that more or less fast, and some (*) have uneven throughput where the snapshots lag varies.
| Card | Cost | Read | Buffering writes | Steady writes | Flush writes |
| ONN 128GB SDXC-1 class-10 3 100mb/s read | N/A | 65MB/s | 13s | 2.2 pic/s | 40s |
| Kootion pro 128GB micro SDXC-1 3 A1 V30 | $14 $0.11/GB | 54MB/s | 13s | 1.8 pic/s* | 92s |
| Lexar professional 256GB micro SDXC-1 UHS-II class-10 3 V60 1000x 150MB/s read 90MB/s write | $56 $0.22/GB | 62MB/s | 12s | 2.8 pic/s* | 42.5s |
| Lexar E-series 512GB sSDXC-1 UHS-1 class-10 3 A1 V30 100MB/s read | $49 $0.10/GB | 64MB/s | 13s | 1.8 pic/s | 92s |
| Lexar Professional 1667x 128GB SDXC UHS-II Cards, 250MB/s Read LSD128CBNA16672 | $59/2 $0.23/GB | 52MB/s | 14.5s | 3pic/s | 30s |
I’m not sure if I should be impressed by my legacy ONN SDcard, or appalled by the “pro” cards performance. Overall all these cards will work for my camera I think. I will never want to shoot that many photos per seconds. The new V rating did not husher new faster cards.
The Lexar Pro 1667X seems to be the best performer but is not a micro-SD card. The 1/2TB Lexar E is a good value and performs well enough for most needs.
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