PSA - Don't Combine ASUS Equalizer With Smart PSUs
I've seen a few people who, out of an entirely reasonable desire to layer their protection, plan to purchase one of the new smart PSU's that are finally hitting the market including those with Seasonic Optiguard, MSI Safeguard+, or Corsair PinProtect and bundling it with what is advertised to be the 'beefiest' 12VHPWR around, the ASUS Equalizer. This post isn't meant to be a commentary on the other issues with the Equalizer and the documented cable burns with it.
Rather, even ignoring all of that, I'm here to tell you why this is still a bad idea.
Why? In short, according to Kirchhoff's Current Law, the crossbar that the Equalizer uses to short all of the pins together will do exactly what it says on the tin... equalize the current at the point of the crossbar.
This is not a good thing if you're counting on your PSU to monitor per pin current and the imbalance is caused by a faulty pin or connection on the GPU side, as the vast majority of documented cases are
This is because all of the pathways from the PSU to the crossbar may be equal, resulting in a roughly equal distribution from the PSU's perspective, but on the GPU side one or two pins might have much higher resistance due to a bad connection or hardware fault. This will result in unequal per pin load on the GPU that your PSU simply can not see.
You are going to want to stick with a cable that lacks the crossbar such as the cable that came with the PSU, or if you're truly wanting another layer of protection, you can look into something like the Corsair ThermalProtect cable, which, while externally similar to the Equalizer, doesn't have a crossbar and instead has a thermal relay which is designed to cut power to the GPU via the sense pins if the temperature of the cable hits 65C.
TLDR: The ASUS Equilizer cable, and any 12VHPWR cable with a crossbar that shorts all the pins together, will make your smart PSU blind to the current flow on your GPU. Don't combine them.