With the workload you mention, a single processor (E5520 or better) should be sufficient. However, you'll need to ensure this meets the guest's requirements. What I would probably start with is:
Hardware:
- 1 x E5520 (or better) CPU
- 1 x DVD drive (alternatively iLO)
- 1 x RAID Controller P41x with 1GB FBWC
- n x SAS HDDs 10k/15k (number of disks depends on your needs for I/Os and capacity)
- 4 x 8GB memory (this will work with a single CPU and you can distribute the modules evenly if you are going to install a second CPU later)
- 2 x Power supplies
Maybe you can get a "Performance Model" for a good price. These models already include e.g. 2 CPUs, 2 power supplies, DVD drive, RAID controeller/FBWC, ...
BIOS settings:
- Intel Virtualization Technology (VT-x) - enabled
- No Execute Disable Bit - enabled
- Power Profile - Static High Performance
Guest installation:
- Windows Server 2003 aligns partitions at 63 blocks (31.5kB) by default. For better disk performance consider to preconfigure the partitions with a partition alignment of 1 MB (the default for newer Windows versions).
- Start low with the vCPUs you provision for the guests and only increase the number of vCPUs if required.
Links:
- HP ProLiant DL380 G6 Server Worldwide QuickSpec
- http://h18004.www1.hp.com/products/servers/options/tool/hp_memtool.html
André