Inspiron 530

Upgrade your Inspiron 530/530s BIOS revision to at least 1.0.12 to enable support for up to 8GB of RAM (more virtual machines). Don't upgrade your BIOS to 1.0.18, as too many complaints currently exist for it, I used 1.0.15. Before running a BIOS update, be sure your machine is plugged into a decent battery backup unit or you could brick your motherboard.

I was converting several of my testbed systems over to VMware ESXi 4.0 and ran into an issue where two of the ESXi servers were reporting one core per socket with one logical processor, even though they were Core 2 Quad's.

ESXi's "Summary" page returns -
Processor Sockets: 1
Cores Per Socket: 1
Logical Processors: 1

To allow VMware ESXi 4.0 to see the correct number of processors for Dell Inspiron 530 systems:

1. Hold "F2" during boot for the Setup menu.
2. Select "Advanced BIOS Features."
3. Press Enter at "CPU Feature."
4. Ensure "Limit CPUID Value" is set to Disabled (Disabled By Default).

ESXi's "Summary" page should now report -
Processor Sockets: 1
Cores Per Socket: 4
Logical Processors: 4