HP 800 g2 twr RAM issue

[ag9665]

I recently I upgraded my hp 800 g2 twr to a 650w psu and when i put in the ram sticks only 1 worked I have 4 ram sticks 8gb each. when I try and put 4 in it starts beeping 3 long beeps and 2 short beeps.

[NonSequitur777]

@ag9665,

Welcome to our HP Community forum!

The PSU upgrade itself is probably not the cause of the RAM issue. A properly connected ATX PSU adapter normally does not affect memory detection.  I imagine you used an ATX power adapter cable specifically compatible with your HP EliteDesk 800 G2 platform such as this one via Amazon-US: Amazon.com: COMeap 24 pin to 6 pin Adapter HP ATX Power Cable Compatible with Z200 Z210 Z220 Z230 Z2....

On the HP 800 G2 Tower, the 3 long beeps + 2 short beeps usually indicate a memory initialization failure.

I would suggest checking the following:

1. Test ONE stick at a time
   Use the same RAM slot each time.

This helps determine whether:

• one RAM stick is faulty,
• or one motherboard slot is faulty.

1. Verify the RAM specifications match
   The HP 800 G2 is picky about RAM compatibility.

Ideally all 4 sticks should be:

• same capacity
• same speed
• same voltage
• same rank/type
• preferably same brand/model

Mixing different DDR4 modules can cause POST failures.

1. Check slot population order
   HP systems often require specific slot ordering.

Usually:

• start with DIMM1
• then DIMM3
• then DIMM2
• then DIMM4

The motherboard silkscreen/manual should show the correct order.

1. Reseat the RAM carefully
   Remove AC power completely first.

A partially seated DIMM can trigger this exact beep code.

1. Clear CMOS
   After hardware changes, HP systems sometimes need CMOS reset before retraining memory.
2. Confirm supported RAM type
   The 800 G2 Tower typically uses:
   DDR4 UDIMM (non-ECC)

ECC or registered/server memory will not work.

If all sticks work individually but fail together, then the issue is usually:

• incompatible mixed RAM,
• incorrect slot order,
• or one weak motherboard DIMM channel.

Kind Regards,

NonSequitur777

[ag9665]

I checked the RAM slots and it turns out dimm 3 and 4 aren't working. All the RAM sticks are the exact same and I tested each one individually in different slots additionally, the PC was advertised as 32GB of RAM.

[NonSequitur777]

@ag9665,

That is too bad. 2 x 8GB is sufficient for most applications, or you could use 2 x 16GB RAM sticks.

Kind Regards,

NonSequitur777

[ag9665]

I would also like to add that one time, while trying to fix it, I changed some settings in the BIOS and reset the CMOS, which fixed the issue. However, when I later reset the BIOS to factory settings because of another issue, it started beeping again. I went back to the bios but I couldn't remember the settings.