read raw = yes and
write raw = yes under
/etc/samba/smb.conf is the way to faster transfers to and from the Raspberry Pi.
I mean, networking on the trusty old Pi—I’m still running a pair of first-generation Model Bs—is known to be ridiculously slow, but this config did take it from about 4 MB/s to near 8 MB/s over Wi-Fi and to an ext4-formatted, externally powered hard drive, which for the time being is plenty for me.
The other Pi, you ask? Has had RetroPie on it for years and still works flawlessly.