u/Global-Fan-3173

Hi everyone,

I’m having a really frustrating issue with my ASUS ZenBook S 14 (UX5406SA, Intel Core Ultra 7 258V, 32GB RAM, OLED), and I’m trying to figure out if this is a known problem or if my unit is defective.

Problem:
Whenever I plug in the charger and do something moderately demanding (for example playing Roblox on higher graphics), the entire system starts lagging in intervals. (Yes, apart from studying, I do very occasionally play Roblox...)

And I don’t mean just the game, I mean:

• Mouse becomes sluggish
• Typing is delayed
• Windows itself becomes very slow
• Everything feels like ~10 FPS

This lasts for ~10–20 seconds, then goes back to normal, then repeats.

Important details:

• This mostly happens when plugged in
• On battery, it seems more stable (still testing)
• Using the original charger
• Happens mainly when gaming, but affects the entire system, not just the game
• It can even lag while I’m typing or browsing if the game is open
• Laptop is basically brand new and cost ~$2200

What I’ve already tried:

• Set MyASUS fan profile to Performance
• Disabled power mode sync
• Tested different Windows power plans
• Adjusted graphics settings in Roblox
• Closed background apps
• Various power/performance tweaks

None of this solved it — if anything, some changes made it worse.

What’s weird:
My partner has a ~$500 laptop that runs Roblox without this kind of system-wide lag, which makes this even more confusing given the price and specs of this machine.

My suspicion:
This feels like some kind of:

• power throttling issue
• firmware/BIOS problem
• or charging-related performance bug

Possibly something related to the new Intel Core Ultra (Lunar Lake) platform?

Questions:

• Has anyone else experienced this on the UX5406 or similar ZenBooks?
• Could this be a BIOS/firmware issue?
• Is this something ASUS has acknowledged?
• Or should I just return/RMA the laptop?

Any help or shared experiences would be hugely appreciated — this is driving me insane 😅

Thanks in advance!

BIOS version: American Megatrends International, LCC. UX5406SA.309, 2025-11-18

Hi everyone,

I’m having a really frustrating issue with my ASUS ZenBook S 14 (UX5406SA, Intel Core Ultra 7 258V, 32GB RAM, OLED), and I’m trying to figure out if this is a known problem or if my unit is defective.

Problem:
Whenever I plug in the charger and do something moderately demanding (for example playing Roblox on higher graphics), the entire system starts lagging in intervals. (Yes, apart from studying, I do very occasionally play Roblox...)

And I don’t mean just the game, I mean:

• Mouse becomes sluggish
• Typing is delayed
• Windows itself becomes very slow
• Everything feels like ~10 FPS

This lasts for ~10–20 seconds, then goes back to normal, then repeats.

Important details:

• This mostly happens when plugged in
• On battery, it seems more stable (still testing)
• Using the original charger
• Happens mainly when gaming, but affects the entire system, not just the game
• It can even lag while I’m typing or browsing if the game is open
• Laptop is basically brand new and cost ~$2200

What I’ve already tried:

• Set MyASUS fan profile to Performance
• Disabled power mode sync
• Tested different Windows power plans
• Adjusted graphics settings in Roblox
• Closed background apps
• Various power/performance tweaks

None of this solved it — if anything, some changes made it worse.

What’s weird:
My partner has a ~$500 laptop that runs Roblox without this kind of system-wide lag, which makes this even more confusing given the price and specs of this machine.

My suspicion:
This feels like some kind of:

• power throttling issue
• firmware/BIOS problem
• or charging-related performance bug

Possibly something related to the new Intel Core Ultra (Lunar Lake) platform?

Questions:

• Has anyone else experienced this on the UX5406 or similar ZenBooks?
• Could this be a BIOS/firmware issue?
• Is this something ASUS has acknowledged?
• Or should I just return/RMA the laptop?

Any help or shared experiences would be hugely appreciated — this is driving me insane 😅

Thanks in advance!

BIOS version: American Megatrends International, LCC. UX5406SA.309, 2025-11-18