AHCI Mode Causes Speaker Noise

[houlty]

Hi,

Recently realised that my drives were in IDE mode as opposed to AHCI mode, so enabled the drivers and made the change in the BIOS. However, now when the pc boots into Windows 7 there is an audible hum from the speakers that wasn't there before... does anybody have any idea what this could be, and more importantly what could solve this problem?

I'm assuming by enabling AHCI mode, there's some additional voltage running through the motherboard which is getting to the speakers (which are hifi speakers powered by a USB dac). I've tried plugging the dac into different usb ports with no luck.

Motherboard is Gigabyte P55A-UD3, if it helps. Drives are OCZ Vertex3 and Samsung EcoGreen 1tb.

I'm guessing this could be a software issue (as it doesn't occur in BIOS / during bootup), but any thoughts are welcome.

Thanks,

houlty.

[Japlabot]

Mute your Microphone and Line In in your volume control

[Noir Angel]

Enabling AHCI shouldn't cause that kind of problem unless one of the components on your board is faulty.

[houlty]

Mute your Microphone and Line In in your volume control

i'll try that in a while. i've switched back to ide for the moment.

if that does fix it, it's surely strange that AHCI mode and not IDE mode would affect this.

Enabling AHCI shouldn't cause that kind of problem unless one of the components on your board is faulty.

hope not. i've had no other issue with the board...

[houlty]

just to update on the issue. i noticed the noise disappeared when there was some load on the cpu, so by deduction i thought it must be related to CPU throttling. i therefore disabled C1E & C3/C6 states in the BIOS and the noise is gone... hurrah!

obviously downside is that throttling no longer occurs, but i can live with that.

edit: i tell a lie, checking CPU-Z throttling does still occur? i'm guessing its now software driven throttling of the cpu, rather than hardware (C1E/C3/C6) throttling...?

[InterceptorX]

I seem the get noise through my speakers/earbuds when I launch certain programs. I really notice it when I am running java applications, aka Minecraft.

[houlty]

i also used to get a noise from an ati gpu i had, but that actually came from the card itself (coil whine), but still affected the speaker output. one thing that really helped that was enabling v-sync.

that particular problem is why i switched to a usb dac (rather than rear 3.5mm socket). That solved the noise through the speakers, but only an upgrade to nvidia solved the noise from the card...