Lenovo Legion Pro 7 Gen 9 Ryzen 9 9955HX RAM Slots Not Detected Fix

Memory type

DDR5-5600 SODIMM

Max capacity

64GB (2x32GB)

Platform

AMD Strix Halo

1

Test Each SODIMM Individually

Power off the Legion Pro 7 Gen 9 completely. Remove the service panel. Remove one SODIMM and boot with only the remaining stick. Then swap sticks and boot with the other. If the system detects different memory amounts depending on which SODIMM slot is occupied, the issue is slot-specific rather than module-specific. If the system detects no memory with one specific SODIMM in either slot, that SODIMM module is faulty. If the system detects memory in each slot individually but not with both installed, the BIOS memory training firmware may need updating for the DDR5-5600 dual-channel configuration on the Ryzen 9 9955HX platform.

2

Update Lenovo Legion BIOS

Open Lenovo Vantage and check for BIOS updates for the Legion Pro 7 Gen 9. The AMD Ryzen 9 9955HX uses the Strix Halo (Krackan Point) memory controller that requires specific DDR5 training profiles for each SODIMM speed grade. Early Legion Pro 7 Gen 9 BIOS versions may fail to complete dual-channel training for certain DDR5-5600 SODIMM brands released after the original BIOS shipment date, causing one slot to appear empty in BIOS and Windows even when both SODIMMs are correctly seated and individually functional.

Per Harith Kamaluddin, 3D rendering professional using Lenovo Legion Pro 7 Gen 9 Ryzen 9 9955HX with 64GB RAM for large scene rendering: “Legion Pro 7 Gen 9 only detected 32GB after installing two 32GB DDR5 SODIMMs. BIOS showed only one slot populated. Reseated both sticks firmly and updated BIOS via Lenovo Vantage. After BIOS update, both 32GB SODIMMs were detected and running in dual-channel DDR5-5600 mode for 64GB total.”

Frequently Asked Questions

Why are RAM slots not detected on Lenovo Legion Pro 7 Gen 9?

One SODIMM module is not fully seated, the BIOS DDR5 memory training firmware does not support the installed SODIMM brand at DDR5-5600 dual-channel, or one SODIMM module is faulty. Test each SODIMM individually to isolate the fault, reseat all SODIMMs firmly, update BIOS via Lenovo Vantage, and use Lenovo-validated DDR5 SODIMMs for guaranteed compatibility.

What DDR5 speed does Lenovo Legion Pro 7 Gen 9 Ryzen 9 9955HX support?

The Legion Pro 7 Gen 9 Ryzen 9 9955HX supports DDR5-5600 as the rated maximum in dual-channel configuration. The AMD Strix Halo memory controller also supports DDR5-4800 at JEDEC standard timing. For maximum memory bandwidth benefiting the integrated RDNA 3.5 graphics and CPU performance, use matched DDR5-5600 SODIMM pairs from the Lenovo-validated compatibility list.

Can I mix different DDR5 SODIMM brands in Lenovo Legion Pro 7 Gen 9?

Mixing DDR5 SODIMM brands is not recommended for the Legion Pro 7 Gen 9 Ryzen 9 9955HX. Different SODIMM brands use different SPD configurations and JEDEC timing tables that may not train correctly together in the AMD dual-channel memory controller at DDR5-5600. If mixing is required, both sticks must be the same capacity and speed rating. The system may fall back to DDR5-4800 for dual-channel operation compatibility between different brand SODIMMs.

Is 64GB RAM enough for heavy workloads on Lenovo Legion Pro 7 Gen 9?

For most gaming, 3D rendering, and professional workloads, 64GB DDR5-5600 dual-channel on the Ryzen 9 9955HX provides substantial headroom. The AMD Strix Halo integrated RDNA 3.5 graphics shares the 64GB system RAM as VRAM, giving the integrated GPU up to 16-24GB of allocated VRAM for graphics workloads. For video editing with large 8K timelines or scientific computing with very large datasets, 64GB can be maximized and a RAM disk or NVMe scratch disk is recommended for temporary file buffers.

Conclusion

RAM slots not detected on the Lenovo Legion Pro 7 Gen 9 Ryzen 9 9955HX is fixed by testing each SODIMM individually to isolate slot versus module faults, updating BIOS via Lenovo Vantage for AMD Strix Halo DDR5-5600 dual-channel training firmware, reseating both SODIMMs with side clips fully clicked, and using Lenovo-validated DDR5 SODIMM modules for guaranteed dual-channel compatibility. BIOS DDR5 training firmware updates are frequently required for newer SODIMM modules installed after the original BIOS release date on the Legion Pro 7 Gen 9.