Memory use and performance issues

I’m having some memory use or performance issues I think. Let me try to

I have a fairly powerful desktop with decent hardware all around. System

Dell Precision 670 Workstation
Running Windows Vista Ultimate x64.
All latest service packs etc.
2 Xeon CPUs 3.2GHz (2 logical processors each). So 4 logical processors each
running at 3.2GHz
6Gigs ram (2GB+2GB+1GB+1GB) DDR2-400 Registered ECC Memory Module.
2 Ultra320 SCSI controller and drives
NVIDIA GeForce 8800GT (512 MB) video card running two 24” monitors.

My Windows Experience Index scores:
Processor: 5.0
Memory (RAM): 4.7
Graphics: 5.9
Gaming graphics: 5.9
Primary hard disk: 5.9

Things to note:

1. With my system rebooted and no programs running I am already using
2.8Gigs of my 6Gigs ram. I must have a lot of processes and services started.
I have no idea which ones to shut off.

2. Considering my other computers have Processor and Memory scores of 5.9
and they have much slower and lesser number of CPUs and not even 64 bit I
suspect my RAM issues is slowing down my processors. I should have 5.9 for a
processor score.

3. My Memory (RAM) score is very low (4.7).

Here is a list of the processes and Services running on my computer:

So what can I do to free up some of this memory being used (What processes
or services can I shut down)? Can I speed up my RAM somehow? Is there
something in my bios that is not turned on or can the RAM be replaced with
faster RAM? It seems really poor that just booting up my computer alone is
using almost 3 Gigs of ram. With my system just sitting and idling, my CPU %
use is between 0 and 1 %. No memory faults are being detected either.

Processor Intel(R) Xeon(TM) CPU 3.20GHz x 2
Memory (RAM) 6.00 GB
Graphics NVIDIA GeForce 8800 GT
Gaming graphics 2558 MB Total available graphics memory
Primary hard disk 93GB Free (279GB Total)
Windows Vista (TM) Ultimate

Manufacturer Dell Inc.
Model Precision WorkStation 670
Total amount of system memory 6.00 GB RAM
System type 64-bit operating system
Number of processor cores 2

Total size of hard disk(s) 1348 GB
Disk partition (C:) 136 GB Free (137 GB Total)
Media drive (D:) CD
Media drive (E:) CDCD/DVD
Disk partition (F:) 711 GB Free (932 GB Total)
Disk partition (J:) 93 GB Free (279 GB Total) <--Windows installed here.

Display adapter type NVIDIA GeForce 8800 GT
Total available graphics memory 2558 MB
Dedicated graphics memory 512 MB
Dedicated system memory 0 MB
Shared system memory 2046 MB
Display adapter driver version
Primary monitor resolution 1920x1200
Secondary monitor resolution 1680x1050
DirectX version DirectX 10

Network Adapter Intel(R) PRO/1000 MT Server Connection
Network Adapter Microsoft Tun Miniport Adapter