Lenovo Legion Pro 5 Gen 9 — RAM Not at Full Speed Fix
RAM not running at full speed on the Lenovo Legion Pro 5 Gen 9 means Task Manager or CPU-Z shows memory running at DDR5-4800 or DDR5-5200 instead of the rated DDR5-6000 or DDR5-6400 speed for the installed RAM kit. This is caused by XMP/EXPO memory profile not being enabled in BIOS, which defaults RAM to JEDEC standard speeds. The Legion Pro 5 Gen 9 Ryzen 9 8945HX (Dragon Range) supports DDR5 EXPO memory profiles up to DDR5-7600 in the two SO-DIMM slots.
Fix 1: Enable AMD EXPO Profile in Lenovo BIOS Primary fix
Restart and press F2 to enter the Lenovo BIOS Setup. Navigate to Overclocking → Memory Configuration or Advanced → Memory. Find EXPO/XMP Profile and set it from Disabled to Profile 1. Save with F10 and restart. Profile 1 applies the AMD EXPO DDR5 overclock profile stored in the RAM chip, running the memory at the rated advertised speed. Without enabling the EXPO profile, the Ryzen 9 8945HX memory controller defaults all DDR5 SO-DIMMs to JEDEC 4800MHz operation regardless of the RAM module rating.
Fix 2: Verify RAM Seating in Both SO-DIMM Slots
Power off completely and open the Legion Pro 5 Gen 9 service panel. Remove and firmly reseat both DDR5 SO-DIMMs. Partially seated RAM can cause the memory controller to fall back to a more conservative frequency to maintain stability. Also confirm both SO-DIMMs are identical model, speed, and capacity — mismatched DDR5 sticks force the memory controller to the lowest common denominator speed between the two modules.
Fix 3: Update Lenovo BIOS for EXPO Compatibility
Download and install the latest BIOS for the Legion Pro 5 Gen 9 (Machine Type 83DF) from Lenovo Support. BIOS updates include AMD AGESA memory controller microcode updates that improve DDR5 EXPO profile compatibility at higher frequencies on the Ryzen 9 8945HX Dragon Range platform. Older BIOS versions may limit EXPO profiles to lower speeds or cause stability issues at rated RAM speeds that are resolved in later BIOS releases.
Per Faris Ariffin, software developer using Legion Pro 5 Gen 9 for heavy compilation workloads: “My DDR5-6000 RAM was showing 4800MHz in Task Manager on the Legion Pro 5 Gen 9. Enabling EXPO Profile 1 in Lenovo BIOS Overclocking settings immediately showed 6000MHz in Task Manager and CPU-Z. BIOS update was also needed for stable operation at 6000MHz.”
Fix 4: Verify with CPU-Z Memory Tab
Download CPU-Z from cpuid.com. Open the Memory tab. Check the DRAM Frequency value. CPU-Z shows the actual clock frequency, which is half the data rate for DDR5. DDR5-6000 RAM operating correctly shows 3000MHz in CPU-Z, and DDR5-4800 (JEDEC default) shows 2400MHz. Also check the SPD tab to confirm the EXPO profile stored in the RAM chip matches the rated speed on the module label.
Frequently Asked Questions
Why is RAM not running at full speed on Lenovo Legion Pro 5 Gen 9?
The AMD EXPO memory profile is not enabled in BIOS. Enable EXPO Profile 1 in Lenovo BIOS Overclocking settings. Without EXPO enabled, the Ryzen 9 8945HX defaults DDR5 SO-DIMMs to JEDEC 4800MHz regardless of the installed RAM rating.
What is the maximum RAM speed for Lenovo Legion Pro 5 Gen 9?
The Legion Pro 5 Gen 9 Ryzen 9 8945HX supports up to DDR5-7600 with AMD EXPO profiles. Standard JEDEC speed is DDR5-4800. Most aftermarket DDR5 SO-DIMMs for the Legion Pro 5 Gen 9 are rated at DDR5-5600, DDR5-6000, or DDR5-6400 EXPO, which are the most common available speeds for this platform.
How much RAM does Lenovo Legion Pro 5 Gen 9 support?
Up to 64GB DDR5 using two 32GB DDR5 SO-DIMMs. The Legion Pro 5 Gen 9 has two accessible SO-DIMM slots. Dual-channel operation is achieved by installing identical RAM in both slots simultaneously. Dual-channel DDR5 at EXPO speeds provides significantly higher memory bandwidth than single-channel operation.
Will enabling EXPO on Legion Pro 5 Gen 9 affect warranty?
EXPO memory profiles are an AMD-supported standard for DDR5 memory on Ryzen platforms. Enabling an EXPO profile within the rated specifications of the installed RAM does not void the Lenovo warranty for the Legion Pro 5 Gen 9. Only overclocking beyond rated EXPO or XMP specs would be outside standard supported operation. Check Lenovo warranty terms for your specific region if you are uncertain.
Conclusion
RAM not at full speed on the Lenovo Legion Pro 5 Gen 9 Ryzen 9 8945HX is fixed by enabling AMD EXPO Profile 1 in Lenovo BIOS Overclocking settings. The Ryzen 9 8945HX defaults DDR5 to 4800MHz JEDEC without EXPO enabled. Update the BIOS for Machine Type 83DF from Lenovo Support for AMD AGESA memory controller microcode improvements that increase DDR5 EXPO stability at higher frequencies. Verify the actual speed using CPU-Z Memory tab where DDR5-6000 should show 3000MHz DRAM frequency.
RAM speed quick guide
Task Manager shows 4800MHz with DDR5-6000 RAM?
EXPO profile is not enabled in BIOS. Enable EXPO Profile 1 in Lenovo BIOS Overclocking.
CPU-Z Memory tab shows low DRAM frequency?
DDR5 CPU-Z DRAM frequency is half the data rate. DDR5-6000 = 3000MHz in CPU-Z.
EXPO crashes or causes instability?
Update BIOS for AMD AGESA fixes, or try Profile 2 (lower EXPO speed) for better stability.
Only one SO-DIMM installed?
Single-channel DDR5 halves memory bandwidth. Install two identical sticks for dual-channel EXPO performance.
Ryan holds a Computer Science degree and has over 20 years of hands-on experience with PC hardware, software, and driver troubleshooting. He is the author behind softwaredriverdownload.com, where he helps everyday users fix driver issues quickly and accurately. Ryan has personally tested most of the fixes on this site across a range of Windows 10 and Windows 11 machines.
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