You have to re-enter all settings anyway after a BIOS flash right? So clearing CMOS will not hurt. A BIOS flash of any other version number is a clean slate...no profiles are kept no settings are kept.

Ideally a new BIOS should be treated as a clean slate...but we are all lazy and often enter previously found stable settings...tweaking some of these can sometimes find different results....often not...sometimes worse.

Clear CMOS is not the same as optimized defaults I guess...but pretty close

I switched to bios2 because bios 1 has a stable Oc that I did not want messed up,
First time of switching and rig would not boot into bios so could not load optimised defaults, even clearing cmos would not boot.
So, loaded 1401 from Usb in the flash port and still could not get into bios.
Re tried numerous times, powering down each time + clearing bios each time. ( also removing plug)
Tried different bios versions and eventually got 1301 to stick, immediately hit f5, f10 and saved, this had to be done within app 4 seconds, if not the whole process had to start again.
Once in 1301 rig would run ok and reboot ok, so rebooted, hit f5 and saved powered down/ cleared cmos / unplugged.
Loaded 1401 in Usb slot and flashed and there we have it! Straight back to the beginning again, unable to post into bios.
Was able to switch back to bios 1 ok and no probs, but switching to bios 2 would not boot.
Tried re download, tried everything, each time it would get a bit further into test ,
Eventually after continually trying I was able to reach bios, quicker than lightening hit f5, f10, saved .
Removed Usb, cleared cmos, unplugged.
Powered up and it booted fine, optimised defaults loaded and reboots ok no problems.
Have since loaded my Oc and rig has been running fine since.
I feel I have a dodgy bios2 but as this is soldered there’s not a lot I can do.
I know if I try flashing again, the same will happen but I will try it just to confirm.
RIG SPECS are as below in my signature @ justinthyme*

Edit: in fact it’s been ok for two days now but i’l bite the bullet and flash it with 1301 and see what happens.( could be a long night.)*

2 and a half hours later I now have 1301 loaded, here’s the sequence of events
*Flashing sequence of errors on bios2 ,, 31 check cpu. 04 test nvram. 99 load vga bios,99 gets to ASUs screen. 99 again. 82 load vga bios. 99 load vga bios. D5 test nvram. 04 test nvram. 99 load vga bios. 82 load vga bios. 04 test nvram. 04 test nvram. 99 load vga bios. 04 test nvram. Powered rig down. 82 load vga bios. Powered down cleared cmos and unplugged. 82 load vga bios. 04 test nvram. 04 test nvram. Cleared cmos, unplugged. Loaded Usb in bios flash port and flashed. 04 test nvram. 04 test nvram. 04 test nvram. 04 test nvram. D5 test nvram. 99 load vga bios. 99 load vga bios. 04 test nvram. 31 check cpu. 04 test nvram. 24 check cpu. 04 test nvram. D5 test nvram. 99 load vga bios. 99 load vga bios. 04 test nvram. 04 test nvram. 04 test nvram. 04 test nvram. Cleared cmos. 92 test nvram. 82 load vga bios. 04 test nvram. 04 test nvram. 04 test nvram. 04 test nvram. Switched to bios 1. Switched to bios 2. 82 load vga bios. 99 load vga bios. Booted to bios then locked up in a9 bios setup menu. Booted to bios, F5, F 10 and saved.. Re booted, OK.
Now I’ve just got to get 1401 back in.
Seems the biggest difference was switching bios back and forth, but may have been just coincidence? I’l find out now with 1401 lol.

Managed to get 1401 flashed to bios 2 but only by going through same problems, loaded my Oc and ran several tests for stability, all ok
Decided to have a go at my ram,, so loaded in settings to get it to 3800 hzs needless to say it locked up in realbench.
Upon rebooting *had same problems getting back to bios.
I am wondering *if bios 2 is not recognising the ram the same as bios 1 does , as all the problems I had during flash I would have otherwise put down to memory stability when booting ,',,,,, mismatch in bios chips perhaps?