There are several competing memory card standards in the professional segment, but the most promising candidate for the next few years seems to be the CompactFlash descendant CFexpress. With speeds of up to 4 GB/s, the standard surpasses the old CompactFlash by a factor of 24! Even the S-ATA-based CFast 2.0 with a maximum of 600 MB/s is left behind.
The problem is that not every card reader can reach such speeds, especially since widespread transfer standards such as USB currently allow a maximum of 2 GB/s (USB 3.2 Gen 2x2) - and even these connections are still rather the exception. Whether the high speeds are needed varies from case to case.
Furthermore, CFexpress is currently a comparatively problematic standard. Although manufacturers of memory cards, cameras, controllers and the like cooperate within the framework of the Compact Flash Association, firmware updates for practically all products in the CFexpress ecosystem are required remarkably frequently to ensure smooth operation.
That's how we test
We also found in the test that not every card reader achieves the maximum speed with every memory card. Therefore, we use a total of three CFexpress memory cards (Angelbird AV Pro XT 660 GB, Lexar Professional 1,750 MB/s, SanDisk Extreme Pro 1,700 MB/s) to measure the maximum possible read speed and give the maximum value in the table.
However, all three measurements for read speed (80%), write speed and usability (10% each) are included in the overall rating. The better the overall rating, the higher the compatibility across different memory cards and the more convenient the operation. The write speed only accounts for 10% of the overall rating, since, as the name suggests, the focus is usually on the read speed of card readers.