I installed the 0x129 BIOS on my Z790 Hero today and I like it. I'm running the Intel "extreme" default, but with the same 1.4V VID limit I was using before, but for temps rather than fear of over-voltage.
It comes with lower VID requests, but also a more agressive LLC. So, even with a 1.4 max VID limit, my Vcore is getting much closer to the limit with the new BIOS and the tighter LLC.
This is probably just a coincidence, but the new BIOS also does better with the memory. I can now run the Asus "tweaked" timings. I tried it in the old BIOS and it wouldn't boot. The new BIOS made two passes of memtest before I got impatient and tried rendering some video in Topaz, and that program seems to like the new RAM timings. The rig is now performing better than ever. -probably because of the RAM, but still...
The 1.4 VID hurts in Cinebench R23, (I don't think that benchmark cares about RAM) but I'm still in the mid 35k range.
If I had a bigger case, I might swap the D15S out for a 360mm AIO and remove the VID limit, but I like my Fractal North (non-XL) and the performance is decent as is.