SM Support lied to you.
It took way to long to figure it out, and I'm kind of embarrassed it took as long as it did to do so. But I found a simple trick to get a HBA to work in slot 4. Put a different adapter in slot 7 first. Don't have or need for another card? Then put your HBA in slot 7.
<rant>
This WTF-type functionality is just last in a long list of disappointments I've had with my X13SAE-F. I've gone from excited to buy it to pretty disgusted with it's overall quality, design, and support. My original board was defective, although was replaced without issue. At the time, it wasn't mentioned anywhere that a 12th gen CPU was required to flash the BIOS to support 13th gen CPUs. It also only stated that bios 2.0 was required to support 13th gen CPUs, but failed to mention that 2.0 wasn't even released.
The IMPI is slow, major options aren't available that are available with other product lines. No flashing of the BIOS, only the BMC firmware. Many screens have no usable information, or of very limited value. The only thing that's of any real use is the remote KVM. Even that though is a PITA to use. Typing it in frequently acts like a key is stuck even if you barely tapped a key, or unresponsive for several seconds as if you never pressed a key. If you're lucky, both happen and you get nothing followed by several dozen letters, numbers, backspaces, etc. as if you never pressed the key...I've noticed is buggy, requiring physical access to correct some issues.
Kiririn was being nice with
his comments regarding the fan speed control. Compared to any "gamer" or "enthusiast" grade board I've used in probably the last decade, it's fan control options are absolute shit.
The board is very clearly NOT a server-grade board, but it's also very clearly not a workstation-grade board either. I'd quit a job if I was given it as a workstation sitting on a desk in an office. I would be embarrassed if I was SuperMicro asking ~$450 for this. I'm even more embarrassed to say that I paid that. But even now several months later, there's still not a readily available option that supports 12/13th gen CPUs and ECC memory.
</rant>