ProDesk 405 G6 Mini upgrade to AMD Ryzen 7 Pro 4750GE

[yeahimliam]

I have a ProDesk 405 G6 Mini that came with a Ryzen 3 Pro 3200GE. I want to upgrade it to a Ryzen 7 Pro 4750GE, but it will not boot correctly. The power light is on, the fan is spinning normally, but I get no display output. The CPU is tested working and when I switch back to Pro 3200GE, the system works fine. I'm on the latest BIOS and the manual says the system supports this CPU. Also, it's nothing to do with the OS since I tested it both on Windows and Linux.

[NonSequitur777]

@yeahimliam,

Welcome to our HP Community forum!

This is an interesting case. Here are some troubleshooting steps and possible explanations for why the Ryzen 7 Pro 4750GE isn’t working in your HP ProDesk 405 G6 DM:

Potential Causes & Solutions:

1. BIOS Compatibility Issues

   • Even though you say that the latest BIOS is installed (verify: 02.17.00 Rev.A released in January 2025), it is possible that HP requires a specific BIOS revision for full support of the Ryzen 7 Pro 4750GE.
   • Action: Double-check the BIOS release notes for any mention of CPU support updates. If possible, try rolling back to an earlier version that may have better compatibility.

2. Auto-detection Failure / CMOS Reset

   • The system might still be storing settings optimized for the Ryzen 3 Pro 3200GE.
   • Action: Perform a CMOS reset after installing the new CPU. This can be done by removing the CMOS battery for a few minutes and then reinserting it.

3. Memory Compatibility Issues

   • The Ryzen 7 Pro 4750GE is a Zen 2 APU, whereas the Ryzen 3 Pro 3200GE is based on Zen+. There could be a memory training issue.
   • Action: Try using a single RAM stick or trying different RAM modules.

4. Graphics Output Issue

   • If using DisplayPort, try HDMI (or vice versa).
   • Some HP BIOS versions require the iGPU to be manually enabled when switching between different APU generations (if available in BIOS).
   • Action: Check if there's a BIOS setting for Integrated Graphics Mode.

5. CPU Firmware Not Included in BIOS

   • While the manual says the 4750GE is supported, based on anecdotal experience, it is possible that early batches of the 405 G6 shipped with a BIOS version that lacks microcode for it.
   • Action: Check if HP has an updated firmware package specifically addressing CPU support.

6. Board Revision Issue

   • Sometimes, HP silently revises motherboards, and not all board versions support all CPUs.
   • Action: Check the motherboard revision (it may be printed on the board) and compare it with HP’s documentation.

 

Next Steps:

1. Reset CMOS and reinstall CPU
2. Try different RAM configurations
3. Check BIOS settings for iGPU and power limits
4. If nothing works, contact HP Support to confirm motherboard revision compatibility

If the Ryzen 7 Pro 4750GE works in another system, the issue likely lies with the HP motherboard firmware or a silent hardware revision that HP hasn’t documented publicly.

Kind Regards,

NonSequitur777

[yeahimliam]

So far, no dice. I've tried different ram, amount of ram sticks, I've done CMOS resets, I've tried different display ports (DP and HDMI), I can't find anything on board revisions, I don't see any options for iGPU in the BIOS or any graphics options, I tried switching the CPU with the previous BIOS and the most recent, and I've gone through support, and they just say they don't offer any hardware support. Hoping someone else has a solution, because it's a real bummer.

[NonSequitur777]

@yeahimliam,

If there is any way to show that the Ryzen 7 Pro 4750GE is not defective such as by installing it in a compatible PC, that would be most helpful.

Unfortunately, I am at the very edge of what I am able to tell you at this point in time.

Hopefully somebody else who may have something useful to add to this discussion thread will come forward.

Kind Regards,

NonSequitur777