Windows 7, Realtek Azalia Onboard Sound, Memory (> 2046MB) Causing Static

I haven't determined the exact amount of memory that is causing the issue, but as someone suggested on a forum somewhere else, limiting the maximum memory in Windows (Start -> Run -> Msconfig -> Boot -> Adv. Options -> Maximum Memory) to 2046 solved this incessant static/cyclical squealing beep sound that I was experiencing. This is an excellent first step, because now I no longer have to turn off my speakers when I'm not blasting music to cover up the twitch-inducing noise.

To be more specific, the artifacts were not caused or affected in any way by the volume of my speakers physically or in Windows, and it didn't change depending on what task I was doing (as some others have mentioned). I could literally mute my speakers in Windows and hear the noises.

I checked my IRQs and there is only an overlap between my Realtek card and some USB bus, but since I am not using any of my USB ports I assume this is not a problem?

Here is my config:

Gigabyte GA-MA790FX-DS5 with BIOS updated to 2009/6/17

Realtek Azalia HD Audio onboard soundcard with drivers updated to the Windows 7 2009/09/07 version

GeForce GTS 250 video card

2 X 2GB memory sticks

AMD 4800+ 1.35GHz processor

etc etc... the rest is insignificant

I am running Windows 7 64-bit RTM with all relevant updates from Windows Update

What is the issue, and is there any way of solving the static while retaining my full 4GB of memory?