According to the latest research published on GitHub by Zephkek, a cybersecurity enthusiast with experience in low-level programming, ASUS ROG gaming laptops have been riddled with buggy BIOS firmware, causing system hiccups. These hiccups occur in the form of stuttering when watching YouTube, pops on Discord calls, the mouse briefly freezing, and other annoying occurrences. According to this investigation, the issue is not any pre-installed "bloat," old drivers, or the operating system itself. The problem actually lies deeply embedded in ASUS BIOS design, where the system-level operations and component management occur.

To find out what happened, the researcher used the LatencyMon tool, which measures CPU interrupt latency. CPU interrupt latency is an important metric as it tells the CPU to stop its current program execution pipeline and move on to another, higher-priority task. On ASUS ROG laptops, like the Zephyrus M16, the first core in the CPU, which is first accessible by the application, is spending over 90 seconds processing interrupts. In that time that specific CPU core is blocked from doing any other work, which leads to stutter, when some time-sensitive workload is running on that core. Behind all of this is the ACPI.sys implementation of the Advanced Configuration and Power Interface (ACPI) standard, acting as the bridge between firmware and the OS to manage power functions (sleep, hibernate, battery, and thermal reporting) and to assist with Plug-and-Play device discovery and resource configuration. This ACPI.sys interprets ACPI Machine Language (AML), which is a code provided by every BIOS maker, including ASUS in this instance.ASUS's ROG laptops are often powered by a discrete GPU like an RTX 30/40 series, and an iGPU paired with the Intel CPU. To handle different power requirements, like running the laptop with battery only, or being plugged in, these laptops have a multiplexer (MUX) switch to switch between the iGPU and the dGPU. However, ASUS firmware is doing weird power cycling that does not make logical sense. In the ultimate stress test for the system, when a laptop is connected to an external display, the system only powers on the dGPU, in this case, NVIDIA. The Intel iGPU is completely powered off and bypassed, so external and internal displays can use the dGPU. However, the system is continuously turning the dGPU on and off, even when it's supposed to be active. No power cycling should be done on dGPU, but the system does it every 15-30 seconds. This behaviour doesn't make sense given that the dGPU is the only active graphics handler, and it is currently powered on.

The report summarizes the findings down to a few root causes. Number one, it misunderstands the interrupt context; number two, it has flawed interrupt handling; and number three, it lacks platform checks, completely bypassing the need to see if the system is in a MUX mode. These issues persist in ASUS models from 2021 to 2024, where they have been recorded on public threads. Models like Strix, Scar, and Zephyrus are affected. Research author claims "ASUS has not responded to this investigation or the documented firmware issues at the time of publication, will update this if anything changes."

Update 08:42 UTC: A TechPowerUp forum user, JustBenching, reports that his 2022 ASUS ROG Zephyrus G14 laptop received an update in early 2024 that resolved the stuttering issues. However, this particular model is powered by AMD Ryzen 7 6800HS and Radeon RX 6800S. We are seeking more information about this issue and whether ASUS has addressed it.

Second update, 16:50 UTC: Another TechPowerUp forum user, SRB151, claims that his 2021 ASUS ROG Zephyrus G15, based on AMD Ryzen 9 5900HX and Radeon RX 6800M GPU also experiences stuttering. The issue even increases after waking up from sleep. This is in line with the original report timeline of models, hence representing another instance confirming the issue.

Update Sep 18th: ASUS confirmed that they are investigating.