Windows 7 drivers general question

[per]

When I first configured my fit-PC2 (1.6GHz) two weeks I installed all W7 drivers found on this site. I reported that it seemed sluggish and that Windows even popped up a screen saying it was slow and suggested to disable Aero. This what on a bare computer with no other software installed or running.

A week ago I reinstalled Windows from scratch and only installed the neccessary drivers. The computer now seems much more responsive and Aero runs no problem.

Question: Why would I need Realtek HD audio drivers when the Intel Accelerator included both audio and video. I am running with just the Intel driver and the audio is absolutely brilliant.

Question: I have not installed the Intel chipset drivers and they don't seem to be needed, what are they for and would I benefit from installing them?

Installed Drivers
* Intel Media Accelerator (newer version from their site) NOT istalled using setup.exe
* IR drivers and EventGhost (with added plugin for Media Center)
* Ralink WiFi driver (newer version from their site) driver ONLY

Not Installed
* Realtek HD audio drivers
* Intel chipset
* Realtek Ethernet drivers