Question Inconsistent performance, stutters, POST failures — suspected aging B450 board or CPU IMC issue (detailed)

[Alexios]

So, I couldn't find anything on the internet about my problem (or I didn't search hard enough) and in general it seems like a lot of things are at fault (probably something is diying) , long story. I have experience with computers (I'm also studying computer science, I've built at least 10 other PCs in my life) and I tried to do everything I know from my experience over the years to solve it. As I said, I couldn't find anything on the internet, so I talked to chat gpt ( i know weird take lol ) but it was the only thing i thought it could help me. Anyways here's a list of the specs and everything you need to know about the 2 month period im trying to fix this. Thanks for your time and please let me know if you find out anything. My goal is to solve it with minimum budget, or at least find out wtf is the problem xd.

System Specs

• CPU: AMD Ryzen 5 PRO 4650G (Renoir, 6-core/12-thread, 65 W TDP)
• GPU: NVIDIA RTX 2070
• RAM: G.Skill Ripjaws V 2×8 GB DDR4-3200 CL16 (Hynix CJR “Deneb” chips)
• Motherboard: MSI B450 Tomahawk (MS-7C02), BIOS E7C02AMS.110 (07/25/2022) (updated)
• PSU: Initially Corsair 650 W, then tested with Be Quiet! System Power 10 450 W 80+ Bronze
• Drives: SSD + HDD
• OS: Windows 11 (unactivated, “Notification mode”)

Symptoms​

• Random massive FPS drops and frame-time spikes in CS2 and other games (e.g. 140 FPS→20–30 FPS, 9 ms→150+ ms).
• Audio stutter & frame skip accompany the freezes.
• Issue appears across all games and even in YouTube/browser playback.
• Sometimes the system “fixes itself” after a few hours or a reboot, then later breaks again.
• Issue seems to get better when I turn off/on the main monitor (weird but reproducible)
• POST sometimes requires two attempts (keyboard/mouse light up → go dark → reboot → successful POST).
• CPU usage during games stays low (10–20%), and single-core Cinebench R23 scoresfluctuate wildly:
  • ~890 → ~1118 → ~1247 (normal ≈ 1250+).
• Multicore Cinebench R23 score ~ 8192–8300, CPU temperature ~ 75 °C at ~ 68 W (normal).
• GPU benchmarks (3DMark) and coil whine tests were fine; GPU never peaks beyond ~ 72 W in worst cases. (probably bottleneck from the poor performance of the cpu, for example it works normally when system stabilizes)

Troubleshooting Steps​

1. Software & OS
   • Fresh Windows 11 installs (twice), all updates, clean drivers.
   • Checked Task Manager for background processes.
   • Ran sfc /scannow & DISM /Online /Cleanup-Image /RestoreHealth — no issues fixed.
2. PSU
   • Tested with two different PSUs (Corsair 650 W and Be Quiet! 450 W) → no change.
   • Verified +12 V rail remains at 12 V ± 5%.
3. BIOS
   • Updated to the latest stable/beta BIOS (7C02v1J5) via M-Flash.
   • Cleared CMOS multiple times manually and via BIOS.
   • Loaded optimized defaults, tested with/without XMP, manual RAM settings (2133, 2666, 2933 MHz).
4. CPU
   • Cinebench R23 single-core & multi-core: low SC usage and fluctuating scores.
   • Ryzen Master / HWInfo: CPU boosts to 4.2 GHz, Vcore at ~ 1.38 V, no thermal throttling.
   • ( i had the Ryzen 5 2600 as my main cpu when i first built it in late 2018 but i had some bios problems and it didnt recognize my gpu (in 2021 i think), long story short i thought the problem was the cpu but it wasnt, it was too late tho i, had already changed to this cpu im rocking now, i had it laying around from another build)
5. RAM
   • MemTest86: 1 pass, no errors. (although i think it needs more testing)
   • Thaiphoon Burner revealed Hynix CJR chips, a known borderline kit on older B450 boards with 4000G APUs.
   • Tested each DIMM slot individually (with one stick at a time) → no conclusive slot failure.
6. Motherboard
   • POST failures, random reboots, frame-time spikes point to power delivery or memory subsystem instability.
   • Aged 2018 board likely experiencing VRM degradation or chipset/RAM trace issues.
   • ASRock B450M-HDV R4.0 recommended (by chat gpt) as a cheap replacement ($50 EUR) that officially supports similar RAM kits with 4000G CPUs.

Final Diagnosis​

• Motherboard hardware degradation/instability is the most likely root cause (~ 70% probability).
• The CPU’s integrated memory controller is stressed by borderline-rated RAM (~ 25% probability).
• The RAM itself is not faulty, but it does push the limits of the aging B450 board.

Next Steps​

1. Buy & install a budget B450/B550 motherboard, e.g. ASRock B450M-HDV R4.0 ( as mentioned before, its the cheapest i could find in greece rn)
2. On first boot:
   • Load optimized defaults
   • Use one RAM stick in the recommended slot
   • Leave XMP off, then test stability at 2933 MHz @ 1.35 V
3. If the system becomes stable, the MSI board was the problem.
4. If instability persists, the CPU’s IMC is likely failing → consider CPU replacement or platform upgrade.

I have exhaustively ruled out software, PSU, GPU, RAM, drivers, and BIOS issues, leaving the motherboard (and secondarily the CPU) as the clear culprit. Any bit of help would be great.
As I mentioned earlier, I've been going back and forth with ChatGPT trying to diagnose the issue. At this point, I'm fairly certain it's hardware-related — possibly VRM degradation or something similar. It’s likely due to age and heavy usage of the motherboard (for context, my Ryzen 5 2600 was slightly overclocked).

What I’m asking for is help:

1. Has anyone encountered a similar issue and can identify what’s going on?
2. What would be the most cost-effective solution?

For example, if the motherboard is indeed the problem, would simply replacing it solve the issue? I'm trying to avoid spending money blindly without being sure what the actual problem is. I’d like to be as certain as possible before purchasing anything.
Could something like reseating the CPU help? I’ve already done a lot of troubleshooting and included as many details as I could in this post.
Thanks in advance!

 

[Lutfij]

Welcome to the forums, newcomer!

Fresh Windows 11 installs (twice), all updates, clean drivers.
Did you recreate the bootable USB installer to rule out a corrupt installer? Did you install the OS in offline mode, with only the drive you wished to install the OS onto? Manually installing the latest drivers for your platform in an elevated command, i.e, Right click installer>Run as Administrator?

Tested with two different PSUs (Corsair 650 W and Be Quiet! 450 W) → no change.
Corsair and Be Quet! are the brands of the PSU, while you've stated the advertised wattage of the units, you should include the model of the units and their age.

Cleared CMOS multiple times manually and via BIOS.
Ideally you're advised to disconnect from the wall and display, then remove the CMOS battery, press and hold down the power button for 30secs to drain any residual power, then reseat the battery after 30mins.

POST sometimes requires two attempts (keyboard/mouse light up → go dark → reboot → successful POST).
When this happens, do any of the onboard debug LED's light up?

ASRock B450M-HDV R4.0 recommended (by chat gpt) as a cheap replacement ($50 EUR) that officially supports similar RAM kits with 4000G CPUs.
IMHO, you shouldn't be investing in parts randomly after an A.I suggestion in hopes of solving an issue. You troubleshoot using donors parts/system...from a friend or neighbor. To add, the board you picked out, has a lackluster VRM design, which can further compound your issues if you're dropping in a processor past the 2000 series due to their higher power draw(in spite of the TDP showing lower, 3000 and up stressed the VRM area).

It could be a faulty or failing BIOS chip even.

 

[Alexios]

Welcome to the forums, newcomer!

Fresh Windows 11 installs (twice), all updates, clean drivers.
Did you recreate the bootable USB installer to rule out a corrupt installer? Did you install the OS in offline mode, with only the drive you wished to install the OS onto? Manually installing the latest drivers for your platform in an elevated command, i.e, Right click installer>Run as Administrator?

Tested with two different PSUs (Corsair 650 W and Be Quiet! 450 W) → no change.
Corsair and Be Quet! are the brands of the PSU, while you've stated the advertised wattage of the units, you should include the model of the units and their age.

Cleared CMOS multiple times manually and via BIOS.
Ideally you're advised to disconnect from the wall and display, then remove the CMOS battery, press and hold down the power button for 30secs to drain any residual power, then reseat the battery after 30mins.

POST sometimes requires two attempts (keyboard/mouse light up → go dark → reboot → successful POST).
When this happens, do any of the onboard debug LED's light up?

ASRock B450M-HDV R4.0 recommended (by chat gpt) as a cheap replacement ($50 EUR) that officially supports similar RAM kits with 4000G CPUs.
IMHO, you shouldn't be investing in parts randomly after an A.I suggestion in hopes of solving an issue. You troubleshoot using donors parts/system...from a friend or neighbor. To add, the board you picked out, has a lackluster VRM design, which can further compound your issues if you're dropping in a processor past the 2000 series due to their higher power draw(in spite of the TDP showing lower, 3000 and up stressed the VRM area).

It could be a faulty or failing BIOS chip even.

First of all, thanks for the fast reply — I really appreciate it.

1. I’ve actually done exactly what you described. I’ve been troubleshooting this issue consistently for the past two months.
2. The Corsair PSU was the one I’d been using since 2018 — I don’t have the exact model on hand at the moment since I’m not home. The Be Quiet! unit, however, is brand new. I was building a basic second PC (for server tasks, etc.), which is why it’s only 450 W. I decided to test the main system with it, since it was the only spare PSU I had available.
3. I’ve cleared CMOS a few times, but it’s possible I still had the display plugged in, and I don’t remember if I actually waited a full 30 minutes. I’ll try doing it again properly, following your exact steps this time.
4. Thanks for reminding me about the debug LEDs — this is actually interesting. Ever since I swapped out the original Ryzen 5 2600 CPU a couple of years ago, the boot process always goes from the VGA LED lighting up briefly, then to the CPU LED, and then it successfully boots. Also, now that I think about it, I did experience a similar issue about a year ago: one day the VGA LED stayed on and the system wouldn’t boot. I replugged everything (GPU, RAM), cleaned things out a bit, and it worked again. That’s actually happened at least twice since installing this CPU. Sorry I didn’t mention that earlier — I had forgotten about it.
5. I completely agree with you — I wouldn’t blindly buy a part just because an AI suggested it. I would only brought up a board after doing some additional research. I’ll also try to see if I can borrow a motherboard or a CPU from a friend to test with, although my second system is Intel-based so it’s not directly compatible.

 

[Alexios]

You're probably right — at this point, I’m seriously considering the possibility of a faulty or failing BIOS chip, especially given the debug LED behavior and the system’s general instability. It really feels like something fundamental isn’t communicating properly or is partially broken, even though the system technically runs.

While I’m still trying to pinpoint the exact cause with your help, I’m currently debating between two paths: either purchasing a budget replacement motherboard (if we confirm the board is the culprit), or saving up to fully upgrade to an AM5 platform (CPU, motherboard, and RAM), keeping my existing GPU, case, and storage.