Concerns about Supermicro POST code and RAM dilemma


Mar 23, 2024
Hi everyone,
recently, I purchased a CPU+motherboard+RAM bundle from eBay to set up my personal homelab. Here is the bundle:

MOBO: Supermicro H11SSL-i
RAM: 8x8GB ECC REG 2133 MHz

The Chinese eBay store sells this bundle, assuring its functionality. Recently, it arrived safely at home, and everything seems to be working fine. The BIOS posts and boots up successfully. Both the CPU and RAM are recognized, and I've even managed to install TrueNAS as the operating system for my homelab.

Upon further inspection, I explored the IPMI Supermicro panel and noticed that under "Post Snooping", the value is 55. After some research online, I found that code 55 signifies "no memory installation", but I'm unsure if this is a reliable indicator. Despite this, my system boots up perfectly fine without any blocking POST codes during the boot phase. I only noticed it in the IPMI panel. Additionally, all 8 RAM slots are recognized by the IPMI panel, as also confirmed by TrueNAS Scale.

The only discrepancy I found in the motherboard manual is that it supports RAM either "1TB Registered ECC DDR4 2666MHz SDRAM in 8 DIMMs" or "2TB Registered ECC DDR4 3200MHz SDRAM in 8 DIMMs (Board revision 2.x required)".

At this point, I'm puzzled as to how everything is functioning smoothly and why the store sells these bundles with the assurance of full functionality, which, from a purely realistic standpoint (since I'm currently using it), it seems to deliver! :D

Now, I have a couple of questions:

1) Should I be concerned about anything even though everything seems to be working fine?
2) If I were to update the BIOS in the future using a Supermicro OOB license, is there a risk of permanently locking these RAM modules at 2133 MHz, potentially causing the system not to boot?

Currently, according to the IPMI panel, I have this BIOS version: 2.0a



Jul 1, 2022
The POST snooping is a non-issue. I have several Supermicro motherboards that report 0x22 there, which isn't even documented. They have run fine for over 6 years.

As for the RAM, the manual lists the maximum that the motherboard supports. This means you can't exceed those numbers. For example, if you installed RAM clocked higher than the listed max, it would be clocked down to the listed max. A DIMM that is rated lower than the max will run at the speed at which it is rated. The slowest DIMM installed will be the speed at which all DIMMs are clocked. The total memory size means that revision 2 boards support 256GB DIMMs max, while others only support 128GB DIMMs max. Your 8GB DIMMs are far below the max, so of course they work. In general, the only way to check the board revision is to look at the silk screened label on the board.

The DIMMs you have now have no relationship to what you might install in the future, and you can't do anything in IPMI that will make the motherboard not be able to accept larger or faster DIMMs, up to the documented limits. You can, of course, use the BIOS to force a slower DIMM speed than the BIOS will pick automatically. But, you can change that back and forth as you wish, just like every other BIOS setting.

I don't have an H11, but my X9 and X11 boards don't show the BIOS version in the IPMI. They do show the IPMI firmware version. To see the BIOS version, I have to enter BIOS setup.
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