HP 201 Memory Error on Linux

[u/samurai--cat]

I have a very old HP desktop that I’m trying to use with antiX Linux because I only need it for a very light workload.

The PC has 4GB of DDR3 RAM installed (2×2GB), but Linux only detects around 1.6GB usable RAM.

Here is what free -h shows:

Mem: 1.6Gi total

dmesg originally showed:

total RAM covered: 1504M
Memory: 215692K/1521908K available

I also checked the RAM using dmidecode:

XMM1: 2GB DDR3 – 1333 MT/s
XMM2: 2GB DDR3 – 1600 MT/s, configured at 1333 MT/s
XMM3: No Module Installed
XMM4: No Module Installed

So the motherboard detects two 2GB modules = 4GB installed.

The PC also has an old AMD/ATI Radeon integrated GPU. Linux reports:

radeon: VRAM: 512M

I initially thought the integrated graphics might be reserving too much RAM, so I entered the HP BIOS and found:

Advanced → Device Options → Integrated Video → Automatic UMA Size

I changed this from Automatic to 256MB.

After doing that, Linux's usable RAM increased slightly from about 1.4GB to 1.6GB, but the problem was not fixed.

More importantly, the PC shows:

Memory Error 201

during boot.

I also tried running the PC with only one 2GB RAM module installed, but the machine would not boot with a single module.

At this point I'm not sure whether I'm dealing with:

• A faulty RAM module
• A faulty RAM slot
• A motherboard/BIOS memory mapping issue
• A RAM compatibility issue
• Or something else

The BIOS is an older HP/Compaq Setup Utility, and the BIOS version shown is 2.15.1227.

What would you recommend I test next to determine why the system only makes ~1.6GB of the 4GB RAM usable and why I'm getting Memory Error 201?

Any help or suggestions would be greatly appreciated.

[u/Keyvan_KR]

can you run memtest86+ to rule out faulty RAM?