I have a 2024 Zephyrus G14 and it has bursts of stuttering which seem to be directly linked to running off USB-C power. It doesn't do it on the original power brick, but on a 70W USB power brick, it slows down massively every now and then, to the point where the mouse cursor is only updating every few seconds and any playing audio starts underrunning buffers. Unplugging USB power immediately clears the issue up for a while. It's fine running off battery, and it's fine when I plug USB power back in, even straight away.
It does other stupid things with power management, too:
- There seems to be some "cooldown" logic that keeps it awake with the fan running for a while (sometimes minutes) after closing the lid. If I just unplug the laptop stick it straight in a backpack, it'll keep doing this (getting hotter and hotter, and burning half of the battery capacity) until it hits the critical high temp shutdown. It's great fun taking it out at the start of a plane flight and finding out it's on low battery and has bbq'd itself.
- Even if I do wait for the fan to turn off before stashing the laptop, when I open the lid and wake it up, it immediately goes into hibernate mode, and I have to wait for it to finish hibernating, turn it back on, and wait for it to boot up, which is really frustrating.
The solution to both of these (for me) is to reassign the power button to be 'hibernate' instead of 'sleep', and to explicitly hibernate it every time I'm packing it up. It's still stupid and annoying, and a damn shame because it's otherwise a really nice laptop. The OLED screen is beautiful and the build quality feels great. I just wish it wasn't crippled.
Your story reminds me a little bit of an issue with the late-Intel macbook pros. If your USB-C charger was plugged in on the left side, and you had an external display connected as well, you'd get crazy thermal throttling. I believe this was because the GPU was on the left side, and so the heat from the charging chip + the GPU resulted in the Macbook deciding to throttle the CPU and crank the fans to max. The solution was to charge on the right side.
https://eshop.macsales.com/blog/61253-power-your-macbook-pro...
There's a similar issue with the old ASUS ROG laptops, my old 17" 2017 one had a higher CPU throttling curve than the GPU, and they shared a heat pipe, so with the CPU at 100%, the GPU would throttle hard and slow games down. The solution was to drop the max CPU down to 90% or something, barely noticeable loss in CPU performance in exchange for a full speed GPU.
(Why did I get another ASUS? Well, after the throttling issue was fixed, the 17" was a beast, it survived dozens of mine site commissioning trips, tons of abrasive iron ore dust, and having a 2" ring spanner dropped on the keyboard (which left a nasty dent but the keyboard still works!). It's still going as my kid's gaming laptop, battery life is now only a few minutes but while plugged in it's fast enough for most modern games. And my partner had just bought a 13" Zephyrus and it was really nice and we hadn't noticed any issues with it.)
Dunno about 2024, but 2023 G14 explicitly documents it can't work at full power when powered by USB-C, because it's USB-C PD supports only 100W compared to the >200W draw of the system. So it throttles just like macbooks with i9 (but those throttled always because one of the problems was overheating VRMs)
I don't expect max performance gaming on USB-C, but it should at least run as fast as it does on battery alone. It should definitely be able to update a mouse cursor and play an MP3.
This isn't just throttling, it's unusable. And it instantly goes away for a while when you disconnect and reconnect the USB-C power supply, even when gaming etc.
Oh, I fully admit that it could be tuned better. At least the 2023 G14 works reasonably well under linux this way, though I'm thinking of going through the ACPI and fixing some of that...