To clarify; it's an Alienware 15 R3.

Welcome to the Dell Community @SB984 

First make sure that your BIOS is up to date.

Then the Chipset drivers.

https://www.dell.com/support/home/en-us/product-support/product/alienware-15-laptop/drivers

If that has no effect then try disconnecting the battery and test while only on AC.

Best regards,

U2

Hi U2 - thanks for the reply.

I'm now getting an error every time I restart my laptop: "The AC power adapter wattage and type cannot be determined. The battery may not charge. The system will adjust the performance to match the power available. Please connect a Dell 240 W AC adapter or greater for the best system performance."

FYI it's the original Dell power adapter.

I updated BIOS and chipset. No change. On battery, folders open in less than 1 second. On mains it's around 8 seconds.

From what I've read, I'll need to disassemble most of the laptop to remove the battery... considering the new boot error, is it safe to say I just need a new adapter?

Thanks

@SB984 

Sounds like it is just beginning to deteriorate.

See if you can find someone with another one to test.

If you have some canned air try blowing out the DC jack on the laptop.

Try cleaning around the center pin on the AC adapters DC jack.

The center pin tells the system what type and wattage the adapter is.

Regards,

U2

Hi @U2CAMEB4ME .

Couldn't find another one to test so I bought another. What turned up is a GA240PE1-00 (what I ordered and what I had previously is a LA240PM160) but both have the same plug and are 19.5V and 12.3A. I tried it and it charges perfectly and the poor performance problem is gone.

BUT... I now have the problem that when plugged in, my trackpad becomes really erratic, cursor jumping all over the screen when I try to use it. Problem goes away when unplugged and doesn't happen with the old adapter. The problem also stops when I touch exposed metal on the laptop. Does this sound like some sort of grounding issue with the new adapter? Seen this before?

Thanks,
Shane