I have benchmarked the FUA/Cache behavior a bit. I don't have an actual filesystem benchmark that does what I wanted and is easy to port to the target so I used: # call with # for loop in {1..3}; do sudo dd if=/dev/urandom bs=1M of=/dev/mmcblk2; done; for loop in {1..5}; do time ./filesystembenchmark.sh; umount /mnt; done mkfs.ext4 -F /dev/mmcblk2 mount /dev/mmcblk2 /mnt for i in {1..3} do cp -r linux-6.2.2 /mnt/$i done for i in {1..3} do rm -r /mnt/$i done for i in {1..3} do cp -r linux-6.2.2 /mnt/$i done I found a couple of DUTs that I can link, I also tested one industrial card. DUT1: blue PCB Foresee eMMC https://pine64.com/product/32gb-emmc-module/ DUT2: green PCB SiliconGo eMMC Couldn't find that one online anymore unfortunately DUT3: orange hardkernel PCB 8GB https://www.hardkernel.com/shop/8gb-emmc-module-c2-android/ DUT4: orange hardkernel PCB white dot https://rlx.sk/en/odroid/3198-16gb-emmc-50-module-xu3-android-for-odroid-xu3.html DUT5: Industrial card The test issued 461 DO_REL_WR during one of the iterations for DUT5 DUT1: Cache, no FUA: 13:04.49 13:13.82 13:30.59 13:28:13 13:20:64 FUA: 13:30.32 13:36.26 13:10.86 13:32.52 13:48.59 DUT2: FUA: 8:11.24 7:47.73 7:48.00 7:48.18 7:47.38 Cache, no FUA: 8:10.30 7:48.97 7:48.47 7:47.93 7:44.18 DUT3: Cache, no FUA: 7:02.82 6:58.94 7:03.20 7:00.27 7:00.88 FUA: 7:05.43 7:03.44 7:04.82 7:03.26 7:04.74 DUT4: FUA: 7:23.92 7:20.15 7:20.52 7:19.10 7:20.71 Cache, no FUA: 7:20.23 7:20.48 7:19.94 7:18.90 7:19.88 Cache, no FUA: 7:19.36 7:02.11 7:01.53 7:01.35 7:00.37 Cache, no FUA CQE: 7:17.55 7:00.73 6:59.25 6:58.44 6:58.60 FUA: 7:15.10 6:58.99 6:58.94 6:59.17 6:60.00 FUA CQE: 7:11.03 6:58.04 6:56.89 6:56.43 6:56:28 If anyone has any comments or disagrees with the benchmark, or has a specific eMMC to test, let me know. Regards, Christian Hyperstone GmbH | Reichenaustr. 39a | 78467 Konstanz Managing Director: Dr. Jan Peter Berns. Commercial register of local courts: Freiburg HRB381782