TL;DR: If you have a dual-CCD Ryzen X3D CPU (9900X3D, 9950X3D, 7900X3D, 7950X3D) on an MSI motherboard, there's a good chance "X3D Gaming Mode" is enabled by default in your BIOS. This disables one CCD and disables SMT, leaving a 9900X3D running as 6 cores / 6 threads instead of 12 cores / 24 threads. Open Task Manager → Performance → CPU and check your core count right now. If it's half of what you paid for, this post is for you.

What's happening

X3D Gaming Mode is a BIOS setting that exists because of a legitimate problem from 2023: when AMD launched the 7950X3D, Windows' scheduler was bad at figuring out which of the two CCDs to send game threads to. Games would land on the non-V-Cache CCD and run badly. The brute-force fix was to just disable the "wrong" CCD entirely. It worked.

In 2026, with Windows 11 24H2/25H2 and current AMD chipset drivers, the scheduler actually does this correctly on its own — provided Xbox Game Bar and Windows Game Mode are enabled. X3D Gaming Mode is now a legacy crutch that costs you half your CPU for no benefit. And yet it seems like MSI still ships it enabled by default on a lot of their AM5 boards.

How to check

1. Open Task Manager → Performance → CPU
2. Look at the bottom right: Cores and Logical processors
3. On a 9900X3D you should see 12 cores / 24 logical processors. On a 9950X3D, 16 cores / 32 logical processors.
4. If you see half of that, X3D Gaming Mode is the most likely culprit.

The fix

1. Reboot to BIOS (Delete during boot on MSI)
2. Navigate to OC → Advanced CPU Configuration → AMD Overclocking
3. Set X3D Gaming Mode → Disabled
4. Set CCD1 Core Control → Auto (this is important - MSI doesn't always reset it when you disable Gaming Mode)
5. Save & exit, reboot
6. Install latest AMD Chipset Driver from amd.com (not Windows Update)
7. Enable Xbox Game Bar (Microsoft Store) and Game Mode (Settings → Gaming → Game Mode → On)
8. Verify in Task Manager that all your cores are back

My results

Tested on a 9900X3D + RTX 5080 + 64 GB RAM, MSI X870E Tomahawk WiFi. In a CPU-heavy game like Star Citizen, this took me from ~20 FPS in dense cities to ~58 FPS, and from "permanently CPU-bottlenecked" to "hitting my framerate cap in normal play." For reference, GPU utilization in the CPU-bound scenes went from 8% to 54% — my 5080 was sitting idle while half my CPU was switched off.

Metric	Before	After
Visible cores	6	12
Visible logical processors	6	24
L3 cache reported	96 MB	128 MB
GPU utilization (CPU-bound game)	8%	54%

The 96 → 128 MB L3 change is the smoking gun: the V-Cache CCD has 96 MB (32 native + 64 stacked), and the frequency CCD adds another 32 MB for 128 MB total. If you see exactly 96 MB on a 12- or 16-core X3D, you're running on the cache CCD only.

Only 6 cores....

All cores!

Notes

• Yes, X3D Gaming Mode existed for a reason on the 7950X3D in 2023. That reason is mostly gone in 2026 with proper Windows + chipset driver setup.
• On single-CCD chips (9800X3D, 7800X3D), X3D Gaming Mode only disables SMT - equally pointless since there's no second CCD to disable. If you've got one of those and only see 8 threads instead of 16, same fix applies.
• This isn't only an MSI issue - other vendors have similar settings (Gigabyte calls theirs "X3D Turbo Mode 2.0"). MSI is just the one I've seen most commonly default to on.
• After any BIOS update, re-check this setting. MSI has a habit of restoring it.
• Games that benefit most: MMOs, simulators, anything with heavy asset streaming or AI processing. Anything CPU-bound. If you've been blaming a game's optimization for poor performance, check your CPU first.

I had this configuration for months without noticing. Hope this saves someone the same blindspot.

EDIT: Adding the BIOS save-confirmation screenshot (missed it the first time around). This is MSI's own log from when I disabled Gaming Mode - note the third line:

CCD1 Core Control: [CCD1 Disable] → [Auto]

That's the smoking gun. Enabling X3D Gaming Mode silently flips a separate setting (CCD1 Core Control) to physically disable the second CCD - it's not OS scheduling, it's a hardware shutoff. Disabling Gaming Mode does NOT auto-reset this on MSI; you have to set CCD1 Core Control back to Auto manually.

BIOS confirmation dialog (disregard that MSI driver utility thing)

TL;DR: MSI motherboards default "X3D Gaming Mode" to enabled on dual-CCD X3D CPUs (9900X3D / 9950X3D, and likely 7900X3D / 7950X3D). This disables one of your two CCDs and disables SMT — leaving you with 6 cores / 6 threads instead of 12 cores / 24 threads on a 9900X3D. In Star Citizen this is catastrophic. I just went from ~20 FPS to ~58 FPS in Area18 by turning it off, and now I'm hitting my 126 FPS cap in quiet zones. Posting this because it took me embarrassingly long to notice.

My setup

• CPU: Ryzen 9 9900X3D
• Mobo: MSI MAG X870E Tomahawk WiFi
• GPU: RTX 5080
• RAM: 64 GB DDR5
• Game: Star Citizen 4.x, tested in Area18 on ArcCorp

What I noticed

Performance in cities (especially Area18) was rough — high-teens to low-20s FPS even with everything tuned. What confused me was that my GPU was sitting at 8% utilization while the CPU was supposedly maxed. That's a textbook hard CPU bottleneck, but on a 9900X3D it didn't make sense.

Opened Task Manager → Performance → CPU and saw this:

• Cores: 6
• Logical processors: 6
• L3 cache: 96 MB

A 9900X3D is a 12-core / 24-thread CPU with 128 MB L3 cache total. Windows was seeing exactly half of it.

The cause

In BIOS under OC → Advanced CPU Configuration → AMD Overclocking, MSI had two settings working together:

• X3D Gaming Mode: Enabled ← default on this board
• CCD1 Core Control: CCD1 Disable ← set automatically by Gaming Mode

X3D Gaming Mode is a holdover from the 7950X3D era when Windows' scheduler was genuinely bad at deciding which CCD to send game threads to. The "solution" was to just disable the non-cache CCD and SMT entirely so games couldn't possibly land on the wrong cores. It worked, but it costs you literally half your CPU.

On Windows 11 24H2/25H2 with current AMD chipset drivers and Xbox Game Bar enabled, the scheduler does the right thing on its own — game threads land on the V-Cache CCD, background processes go to the frequency CCD. X3D Gaming Mode is no longer needed and actively hurts you in CPU-bound situations like SC's cities.

The fix

1. BIOS → OC → Advanced CPU Configuration → AMD Overclocking
2. X3D Gaming Mode → Disabled
3. CCD1 Core Control → Auto (verify this — MSI doesn't always reset it automatically when you toggle Gaming Mode off)
4. Save & exit, reboot
5. Windows: install latest AMD Chipset Driver from amd.com (not Windows Update), enable Xbox Game Bar and Windows Game Mode, launch SC once to let Game Bar register it as a game
6. Verify in Task Manager: 12 cores / 24 logical processors / 128 MB L3 cache

My results

Scenario	Before	After
Area18 (worst case, CPU-bound)	~20 FPS	~58 FPS
Quiet zones (space, small outposts)	wasn't tracking but rough	hitting my 126 FPS cap consistently
GPU utilization in Area18	8%	54%
Cores visible to Windows	6	12
L3 cache visible	96 MB	128 MB

The "hitting my FPS cap in quiet zones" part is the real tell — it means the system is no longer CPU-bottlenecked in normal play. You only feel the limits when the game itself becomes the bottleneck (server FPS, asset streaming in dense cities). That's the state SC was designed to run in.

Notes

• This is specifically a problem on dual-CCD X3D CPUs (9900X3D, 9950X3D, 7900X3D, 7950X3D). If you have a 9800X3D or 7800X3D you're single-CCD and unaffected by the CCD part, but X3D Gaming Mode may still pointlessly disable your SMT.
• This is primarily an MSI default. ASUS, Gigabyte and ASRock have similar features but generally don't enable them by default (Gigabyte calls theirs "X3D Turbo Mode 2.0"). Check your BIOS regardless.
• After every BIOS update, re-check this setting — MSI sometimes restores it on updates.
• Server FPS in SC is the great equalizer. On a fresh shard with healthy server FPS, the difference is dramatic. On a 6-hour-old shard you'll still feel limited regardless.

only 6 cores...

All cores!

Hope this helps someone. Star Citizen punishes hidden bottlenecks like nothing else, and I had been blaming the game when half my CPU was just... switched off.