HP Z220 RAM Issue After Adding Extra Stick – Now Original RAMs Won’t Work Together

[hanzuk]

Hi,

I have a HP Z220 workstation (Xeon E3-1240 v2) with a strange RAM issue that started right after I added a third RAM stick. I’ve been using 2x4GB DDR3 RAM sticks (same brand, speed, and voltage) for months without any problem.

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🔧 What Happened – Step by Step:

1. I had two 4GB sticks installed (let’s call them RAM A and RAM B).
  → Both were working perfectly together in dual-channel.

2. I tried adding a third 2GB stick (RAM C).
  → As soon as I installed it, the PC gave 5 red beeps, and no display.

3. I removed RAM C and tried to boot with A and B again.
  → Still got beeps — system didn’t post.

4. After some swapping:

I tested each RAM stick (A and B) individually

Both worked fine on their own, in all slots

But the moment I installed both together again, the system started beeping or only detected one stick

5. I then tried using the RAM that was working in all slots (RAM A) with another known working stick.
  → Same issue — system would beep or detect only one stick.

6. I cleaned the RAM slots, reset the CMOS, replaced the CMOS battery, and even updated BIOS.
  → Nothing fixed the problem.

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🧠 Observations:

All RAM sticks are identical specs (1333MHz DDR3, same brand, same voltage — confirmed by testing and visual inspection)

All slots work (individually tested with RAM A)

Each RAM works on its own, but they refuse to work together anymore, even if it’s the same pair that used to work fine before

The issue began only after trying to add a third RAM stick

RAM C is now removed — but damage (software/firmware?) seems to persist

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❓ Questions:

Could adding the third stick have somehow confused the memory controller or corrupted SPD/BIOS settings?

Has anyone experienced this before with Z220?

Is there a way to fully reset memory training or SPD cache?

Could this be related to ECC/non-ECC mismatch even if RAM specs match?

Any advice would be appreciated. I'm currently stuck with just one RAM stick in use and can't get dual-channel or full memory to work anymore.

Thanks in advance!

[Bill_To]

Greetings @hanzuk 

Welcome to the HP Forum.

Well, that's a head scratcher.

Resetting CMOS should have reset the BIOS. I would think all MB functions should be good to go after resetting CMOS.

You have stated "Could this be related to ECC/non-ECC mismatch even if RAM specs match"?

Did you install non-ECC memory in the third memory slot when the existing memory modules are ECC? I don't know what effect this would have. I've never done this.

I can't see, however, anything is possible, doing what you might have done (mixing ECC and non-ECC memory modules??) permanently breaking something.

I also can't say the following suggestion would help since I have never encountered your problem. But I would probably reset CMOS and then remove the CPU. Then reinstall the CPU to see what happens.

The CPU memory controller may be freaking out. Maybe the system will be happy after you reset CMOS and reinstall the CPU.

I can't think of anything else to try.

Very unusual situation.

Regards