Hi everyone,
I would like to share my experience with a card which is not listed as a good choice for 240Mhz overclock, but it works to me.
Camera: Canon 5d Mark III
Firmware: 1.1.3
ML settings: card spanning and 240mhz overclock activated.
ML build: Danne's crop rec 4k_mlv_snd_isogain_1x3_presets_2023Feb03.5D3113
SD card: Lexar Professional 1667x SD card 128 GB, SDXC UHS-II, up to 250 MB/s. (camera low-level formatting)
CF card: Lexar Professional CF 128 GB 1066x (160 MB/s) UDMA 7 (camera
low-level formatting)
PC card reader: Trascend TS-RDF9K USB 3.1/3.0
Benchmarks in video mode
Sd card benchmark:
Sd and CF card benchmark:
Benchmarks in photo mode:
Sd card benchmark:
Sd and CF card benchmark:
CrystalDisk Mark benchmark:

According to the list of Sd 'working' cards under 240Mhz overclock, I bought a SanDisk 128 GB Extreme PRO, SDXC up to 200 MB/s, UHS-I, Class10, U3, V30. Unfortunately overclock doesn't work properly, in my case. I mean it works for a while and I can run some benchmarks:
Benchmarks in video mode:
160Mhz overclock
192Mhz overclock
240Mhz overclock
If I try to record a video, under 240Mhz overclock, the camera becomes unstable. After that, if I run any benchmars I get unreal speed readings:
240Mhz
Nothing to do even lowering the overclock to 160Mhz
160Mhz
The camera, paired to the overclocked SandDisk, isn't stable at all. The situation doesn't change switching from SDR 104 to SDR 50 or warming the card up. Peraphs the problem is just limited to such a card.
My SanDisk 128 GB Extreme Pro:


CrystalDisk Mark benchmark:

Under PC, values seem to be coherent with the results of other users.
Any possible setting before returning it to the seller (bought by Amazon) and buying the 170mb/s version? It would be warmly appreciated.
Thanks for your support.
All the best.