MSI B450 Tomahawk Max RAM Stuck at 2133 MHz After BIOS Update

XMP enabled but RAM still runs at 2133 MHz? This happens after BIOS updates on MSI B450 boards. Here's how to get your rated speed back in 30 seconds or less.

You flashed your MSI B450 Tomahawk Max to a newer BIOS, booted up, and noticed your DDR4-3200 kit is running at 2133 MHz. XMP is enabled in the BIOS. Task Manager agrees. So does CPU-Z. Annoying, right?

This is one of the most common post-BIOS-update complaints I see on this board. The fix usually takes under a minute. Sometimes it takes 15. I'll walk you through all three stages. Stop as soon as your RAM hits its rated speed.

Stage 1: The 30-Second Fix — Reseat XMP Profile

Here's what nobody tells you: after a BIOS update, the board often keeps the XMP toggle showing "Enabled" in the menu even though the actual memory timings got wiped back to JEDEC defaults. The BIOS is lying to you. You need to force it to re-read the profile.

Restart the PC. Tap Delete repeatedly as it boots to enter the BIOS.
You're now in Click BIOS 5 (the red and black interface on this board). Look at the top left — you should see the current CPU and memory speed. If it says 2133 MHz, problem confirmed.
Click OC in the left sidebar. You'll land on the overclocking page.
Find Extreme Memory Profile (XMP). It probably says Enabled or shows Profile 1.
Change it to Disabled. Press F10 and save. Let the PC boot to Windows normally.
Shut down completely. Wait 10 seconds. Power back on and enter BIOS again.
Go back to OC. Set XMP back to Enabled or Profile 1. Press F10 to save and exit.

After the reboot, open Task Manager (Ctrl+Shift+Esc) and click the Performance tab, then Memory. You should see your rated speed, like 3200 MHz. If you do, you're done. Stop reading.

If it's still 2133 MHz, move to Stage 2.

Stage 2: The 5-Minute Fix — Clear CMOS and Reconfigure

Sometimes the BIOS update leaves a stale NVRAM entry that blocks XMP from applying, even when the toggle looks right. Clearing CMOS wipes everything back to factory defaults and forces a clean re-read.

Shut down the PC. Flip the power supply switch to O (off) and unplug the power cable.
Open the case side panel. Locate the two-pin JBAT1 jumper — it's near the bottom edge of the board, just below the CMOS battery. On the Tomahawk Max it's labeled clearly in white silkscreen.
Take a flathead screwdriver or the jumper cap that came with the board and bridge the two pins for 10 full seconds.
Remove the bridge. Plug the power cable back in, flip the PSU switch on, and boot.
The board will POST with a message like "CMOS has been reset. Press F1 to enter setup." Hit F1.

Now set the BIOS up like you would on a fresh build:

Set the date and time.
Go to OC and enable XMP Profile 1.
Leave DRAM Frequency on Auto — XMP will override it.
Save with F10 and reboot.

Check Task Manager again. If you see your rated speed, done. If it's still 2133 MHz, Stage 3 is where the real fix lives.

Stage 3: The 15-Minute Fix — Manual DRAM Frequency and Voltage

Here's my opinion after setting up dozens of these boards: the MSI B450 Tomahawk Max has firmware quirks with certain memory kits after BIOS versions 7C02v3B and later. The XMP profile gets flagged as "unstable" by the board's memory training routine, and instead of failing to POST, it silently falls back to 2133 MHz. You fix this by manually entering the frequency and voltage so the training routine has less to guess at.

You'll need to know your kit's rated specs. If you don't remember, CPU-Z under the SPD tab shows the XMP profile timings. Write these down: rated frequency, primary timings (like 16-18-18-38), and rated voltage (usually 1.35V).

Enter BIOS. Go to OC.
Set XMP to Disabled. Yes, disabled. You're doing this manually.
Set DRAM Frequency to half your rated speed. Example: for a DDR4-3200 kit, pick DDR4-3200 from the dropdown. The number in the menu is the effective speed, so 3200 = 1600 MHz base. Don't overthink it.
Scroll to Advanced DRAM Configuration. Enter your kit's primary timings manually, in order: tCL, tRCDRD, tRCDWR, tRP, tRAS. Example for a 3200 CL16 kit: 16-18-18-18-38.
Back on the main OC page, find DRAM Voltage. Set it to 1.35 for most kits. Samsung B-die kits might need 1.40 to hold 3200 CL14.
Press F10 to save and reboot.

After the reboot, check Task Manager. Your RAM should now run at the rated speed. If it doesn't, drop the frequency one step (3200 → 3000) and try again. Some Ryzen 2000-series CPUs on B450 boards can't hit 3200 MHz stable, even when the kit can. That's a memory controller limit, not a RAM problem.

Real-world trigger: this exact issue showed up constantly after MSI pushed BIOS 7C02v3F in early 2023. Guys who'd been running 3600 MHz kits on their 3700X for two years flashed the update for the AGESA fix and woke up to 2133 MHz. The XMP toggle said Enabled. The RAM said otherwise.

If Nothing Worked — What to Check Next

Three other things bite people here:

Wrong DIMM slots. On the Tomahawk Max you must populate A2 and B2 first — the second and fourth slots counting from the CPU. Using A1/B1 caps you at 2133 MHz on most BIOS revisions. This is a documented MSI quirk, not a rumor.
Re-flash the BIOS. If you jumped multiple versions (say 7C02v37 to 7C02v3H), the update may have partially failed. Use M-FLASH from the BIOS itself with the file on a FAT32 USB stick. Flash to the latest non-beta release.
One stick at a time. Test each DIMM solo in A2. If one stick trains at 3200 and the other doesn't, you're looking at a bad stick or a mismatched kit.

One more thing — if you're on a Ryzen 5 1600 or 2600, 2933 MHz is often the ceiling. Not because your RAM is slow, because the Zen+ memory controller gives up above that. Set your XMP, then manually cap DRAM Frequency at 2933. That's the real fix for those chips.

If you're on Zen 2 or Zen 3 (3600, 5600, 5800X3D), 3200–3600 MHz should apply cleanly once you follow Stage 3. The board handles it fine. The firmware just needs a nudge.