Trouble With DDR5 Underclocking on AM5 Motherboard and 4 DIMMs
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TechGuru92
I've been setting up a workstation for FEM simulations and machine learning training, but I'm facing some issues with my DDR5 memory. My setup includes an AMD Ryzen 7 8700G CPU, ASUS B650E MAX GAMING WIFI motherboard, and a total of 128 GB of RAM using 4 DIMMs. While the system seems stable, the memory speed appears to be heavily downclocked. The BIOS shows it at 3600 MT/s, but HWiNFO reports it closer to 3000 MT/s. I realize that using 4 DDR5 DIMMs on AM5 isn't optimal, but my memory kit should theoretically support speeds up to DDR5-4800 with the right configurations. Unfortunately, when I try enabling EXPO or manually setting the speed to 4800 MT/s with JEDEC timings, the system won't POST. It only boots properly with the auto settings, which run at a reduced speed. I feel like I'm losing out on a lot of potential bandwidth. I'm looking for insight on whether this behavior is expected with this setup, any tweaks that could help me stabilize at higher speeds, or if this is simply the limit of the integrated memory controller (IMC) with four dual-rank DIMMs.
Answers
According to AMD, your CPU should support JEDEC 3600 speeds with 4 DIMMs, so it sounds like everything is working as it should. You might have to stick with that unless you're really keen on tuning it.
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Yeah, that's expected behavior when you're running 4 DIMMs. You’re effectively pushing into overclocking territory, and there aren’t any one-size-fits-all settings. You’ll likely need to tweak the settings manually and stress test them to achieve better speeds.
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Have you tried updating your BIOS? That might help with the memory speed issue. Also, there's a chance you just drew the short straw with your silicon quality; sometimes, the memory controller isn't up to par. It happens! I'll suggest checking those updates first.
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Thanks for the info! I didn’t realize 3600 MT/s was the expected limit for this setup. Tuning just isn’t for me, so I guess I’ll have to live with the current speeds.
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