As part of tightening security, FACEIT anti-cheat has started requiring IOMMU and DMA protection to be enabled on MSI motherboards. Gigabyte and ASUS boards don’t currently have the same requirement. After these settings are turned on, a common complaint on MSI systems is that “the game feels heavier.” Below we cover what these settings are, why they are required and what you can do about it.
What are IOMMU and DMA?
DMA (direct memory access) lets a device such as a graphics card or an NVMe drive read and write memory directly, without waiting on the CPU. It is one of the things that make a computer fast.
IOMMU is the gatekeeper for that access. The operating system decides which device can touch which region of memory. “Kernel DMA Protection” in Windows relies on this hardware.
Why does anti-cheat require it?
A type of cheat that has become common in recent years uses a PCIe card installed in the computer to read the game’s memory from outside. Because the card doesn’t run inside the game, traditional anti-cheat has a hard time detecting it. With IOMMU enabled, devices can no longer access memory freely, which makes this kind of cheat largely ineffective. In other words, the requirement exists for fair play, and turning it off to play FACEIT is no longer an option.
If FACEIT requires a setting, don’t turn it off. The right approach is to win back the performance you lose with that setting enabled from somewhere else.
Impact on FPS and latency
With IOMMU enabled, device memory access goes through an address translation step, and the system can see extra interrupt overhead. In competitive games this shows up less in average FPS and more in 1% low FPS and frame time variance. Players describe it as “same FPS, but the game doesn’t feel smooth.”
How big the impact is depends on the motherboard, the BIOS version and the installed devices, so giving a single number wouldn’t be accurate. Don’t decide without measuring on your own system.
How to measure it on your system
- Install a frame time capture tool such as CapFrameX or PresentMon.
- In CS2, record 60 seconds on the same map in the same scene. Repeat this three times.
- Look at 1% low FPS and the longest frame time, not average FPS.
- Repeat the same test after updating the BIOS or changing a setting.
| What to check | Why |
|---|---|
| BIOS version | Manufacturers improve IOMMU behavior through updates. Don’t test on an old BIOS. |
| Graphics card and chipset drivers | Interrupt handling also changes on the driver side. |
| Installed PCIe and USB devices | Unneeded cards and controllers increase interrupt load. |
| Background software | RGB and motherboard utilities can make interrupt latency worse. |
Measurement results
Measurements collected on MSI motherboards will be shared on this page. If you noticed a difference after FACEIT made you enable these settings, you can let us know on X.