Causes
- The XMP 3.0 or EXPO profile was never enabled every DDR5 kit ships with a JEDEC fallback of 4800 MT/s so it boots on any board. The FURY Beast 32GB DDR5-6000 CL36 kit only reaches its rated 6000 MT/s after you load the saved profile in BIOS, and a fresh build or a BIOS update resets that setting to Auto.
- The board reverted to safe defaults after a failed memory training when a 6000 MT/s profile fails to train, most boards retry two or three times and then boot at JEDEC speed instead of showing an error. If you enabled the profile, saw a black screen, and the machine later came up normally, the kit is probably running at 4800 because the board gave up on the profile.
- The two modules are in the wrong slots a 2 x 16 GB kit belongs in the second and fourth slots from the CPU (A2 and B2 on most four-slot boards). Populating A1 and B1, or mixing a 2-DIMM kit into a four-DIMM layout, leaves the daisy-chain trace topology untuned for 6000 MT/s and often caps the kit at 4800 or 5200.
- An outdated BIOS or AGESA build cannot train the kit at 6000 early AM5 firmware in particular had weak DDR5 training, and plenty of boards shipped with a BIOS that could not hold a 6000 CL36 kit stable. Kingston validates the kit against each board's QVL, but the validation assumes current firmware.
- The CPU memory controller or board topology is the limit a 6000 MT/s kit is a two-DIMM sweet spot. If you add a second kit (four DIMMs), drop to a cheaper board with a weaker memory VRM, or run a CPU whose integrated memory controller struggles above 5600, the profile can silently fall back. Memory Context Restore and Fast Boot make this worse because they can restore an old failed training result instead of retraining.
How to Fix
- Load the profile in BIOS and save. Restart and press Del or F2 during POST. On Intel boards open the XMP section and select XMP Profile 1. On AMD boards open EXPO (sometimes listed as D.O.C.P. on ASUS) and select EXPO Profile 1. Press F10, confirm, and let the machine restart. Expect 30 to 90 seconds of memory training on the first boot; do not cut the power.
- Verify the actual speed, not the BIOS label. In Windows open Task Manager > Performance > Memory and check the Speed figure, or use CPU-Z > Memory where a 6000 MT/s kit reports a DRAM Frequency near 3000 MHz because DDR is double data rate. A reading of 2400 MHz means you are still on 4800 MT/s.
- Move the modules to slots A2 and B2. Power down, unplug the PSU, and move both sticks to the second and fourth slots counting away from the CPU socket. Push until both latches click; DDR5 DIMMs need noticeably more force than DDR4 and a half-seated module can train at a lower speed.
- Clear CMOS, update the BIOS, then re-enable the profile. With the PSU unplugged, short the Clear CMOS jumper or hold the rear Clear CMOS button for 10 seconds. Boot into BIOS, use the vendor's flash utility (Q-Flash, EZ Flash, M-Flash, BIOS FlashBack) to install the latest stable BIOS, then load XMP or EXPO again. Do not use a beta BIOS unless the release notes mention DDR5 training fixes.
- Set the AM5 link ratios manually if EXPO still drops. On AMD, confirm UCLK == MEMCLK (1:1 mode), set FCLK to 2000 MHz, VDDIO to 1.35 V, and SoC voltage between 1.20 V and 1.25 V. Keep SoC at or below 1.30 V. On Intel, check that Gear 2 is selected and VDDQ/VDD sit at the profile's 1.35 V.
- Disable Memory Context Restore while you tune. Turn off Memory Context Restore and Fast Boot so the board runs a full training pass on every cold boot. Once the kit holds 6000 MT/s across several restarts, re-enable Memory Context Restore for faster boots.
- Step down one notch to find the stable ceiling. If 6000 will not hold, set 5600 MT/s with the same CL36 timings or set 6000 with CL38. A kit that is stable at 5600 but not 6000 usually points at the CPU memory controller or the board, not at the modules.
- Stress test before you call it fixed. Boot MemTest86 from a USB stick and run at least four full passes with XMP or EXPO enabled, then run an hour of TestMem5 with the anta777 profile or OCCT's memory test. Any error at the rated 1.35 V profile means the kit or the slot is faulty and the kit should go back to Kingston for a warranty replacement.