@rafel
Was the ME FW v11.8.50.3460, updated to that version with a BIOS update from ASUS? I’m not certain but I was under the impression that ME FW v11.8.50.3460 was the one that was patched for the spectra vulnerability, but I might be wrong, i should have check before posting this, because memory is not serving me well.
But what I was going to say was if you want to update to the latest ME FW for your mobo you can always disable with spectra as you have done with your current version. Maybe first do a few benchmarks with your current setup with spectra disabled and enabled to see what impact the patch has on your system, then do the same after updating the ME FW, and compare. Just a thought