Stumped on CPU upgrade

[ScientistAsHero]

Hi everyone,

So I'm not exactly a beginner computer user, but I am definitely not a hardware guy. I've run into an issue installing a new CPU and was hoping someone could help.

I have a HP Desktop (M01-F0033w). I think I picked it up in about 2022 or so..? It is a basic pre-built computer from Walmart. It came with a Ryzen 3 3200G processor with integrated Radeon Vega 8 Graphics. The baseboard is a HP 8643 with a4 socket. Not too long ago, I bought a dedicated GPU for it, a Radeon RX 550. (I am aware that this GPU is not that much better than the onboard CPU graphics, but whatever, it has been a learning experience for me, and anyway I don't think the GPU is responsible for the trouble I've been having.)

Due to the fact that my PC is getting pretty ancient, I wanted to get a new CPU for it, but I understood I was limited in what newer hardware my motherboard could support. So I ended up getting a Ryzen 7 3700x. I made sure it could fit the a4 socket in my motherboard beforehand, and I updated the BIOS. But when I installed it, applied the thermal paste, and put the heatsink and fan back on, and pushed the power button, basically nothing happened other than the indicator light blinked and the fans spun for like half a second. After that no response at all.

I took out and reinstalled the CMOS battery, I unseated one RAM stick, made sure all my connections were secure, but still nothing.

However, when I put the old CPU back in, the computer started just fine and everything loaded up perfectly. If I repeat the process, I get the same exact result, every time.

I thought it might be a PSU issue, but from what I've been able to find online, the Ryzen 3 and the Ryzen 7 have the same TDP of 65w. (I understand that the wattage might vary if I was doing something computationally intensive, but this was just from turning on the computer.) Basically, it just doesn't seem like me adding this new CPU is increasing the total wattage demanded from the components of my system. And my PSU is only 180w, which I know is low, but I don't quite get why it would suddenly be an issue now because the wattage of the new and old processors is the same.

I've read that it could also be a BIOS issue, that BIOS doesn't recognize the new processor and so doesn't start, which seems like it could also possibly be the case because of how it ATTEMPTS to start right after I've turned it on, but I don't know. I did download and install the latest BIOS from HP's website, which was from late 2023. (That was the only option available for my baseboard, 8643.) But it doesn't make any difference.

On HP's upgrade specifications page, it specifically lists the new CPU I bought as being a compatible upgrade to the motherboard I have.

Any help would be greatly appreciated.

[Garp_senchau]

@ScientistAsHero, Welcome to HP Support Community,

Thank you for posting your query; I’m here to help by guiding you through steps to resolve this issue

Hey there! 😊 Thanks for the detailed explanation — you’re clearly putting in the effort, and you’ve already done quite a bit right (BIOS update, thermal paste, checking connections, etc.). Let’s dig in and see what could be causing this Ryzen 7 3700X upgrade to stall.

Here's what we know:

Your PC: HP Desktop M01-F0033w (Motherboard: HP Erica 8643, Socket AM4)

Original CPU: Ryzen 3 3200G (works fine)

New CPU: Ryzen 7 3700X (fails to POST)

BIOS: Updated to latest (from HP site, late 2023)

PSU: 180W

Dedicated GPU: Radeon RX 550

HP’s official documentation does list the Ryzen 7 3700X as a supported upgrade

Why it won't POST with the 3700X

PSU Power Delivery (Most Likely Culprit)

While the TDP is indeed 65W for both CPUs, the Ryzen 7 3700X has 8 cores and 16 threads, which means it draws more peak current and requires more stable power delivery, especially during startup (POST). Your 180W PSU is very minimal, especially with a dedicated GPU now also drawing power.

Try this:

Test with a higher-wattage PSU (at least 300W–400W just for testing purposes).

RAM Compatibility

Sometimes, when a new CPU with a different memory controller is installed, especially jumping from Picasso to Matisse, it may require a RAM reseat or swap.

Try this:

Use just one stick of RAM in the slot closest to the CPU.

I hope this helps.

Please feel free to reply here if you have any questions or if you need further clarification on any of the steps. 

Take care and have a good day. 

If my response helped, please mark it as an Accepted Solution! ✅ It helps others and spreads support. 💙 Also, tapping "Yes" on "Was this reply helpful?" makes a big difference! Thanks! 😊

Regards,