Here's the motherboard's specs. I copied this off of Dell's website:
Socket Type Socket - T (LGA 755)
CPU Support Pentium 4 from 631(3.0G) upto 661(3.6G)
Pentium D from 920(2.8G) upto 950(3.4G) and 955(3.46G)
FSB Support 800MHz/1066MHz
Chipset(Northbridge/Southbridge) NVIDIA nForce 4 SLI (NVIDIA C19/MCP 55)
Upgradable BIOS 4Mb Flash EEPROM
Memory standard 533 / 667DDR2 (240 pin)
Number of memory slots 4 slots (populate in pairs for dual channel)
Memory Modules supported 512MB, 1GB, 2GB
Max memory supported 8 GB (using 64-bit OS)
Audio controller Sigmatel 9227 on High Definition Audio Interface
Audio specifications 24-bit ADC, 24-bit DAC
7.1 channels
~90 dB signal to noise ratio (tested)
Expansion slots 2-PCIex16
1-PCIex1
1-PCIex8
3-PCI
Internal Connectors 1 - ATA100 channel (upto 2 Devices)
6 - SATA || (3.0 Gb/sec, NCQ with compatible drives)
SATA RAID 0/1/JBOD supported
1 - FDD channel
3 - PWM controlled fan headers (with compatible fans)
2 - USB 2.0 (USB ports 8 & 9)
1 - IEEE 1394a
1 - Front panel (audio, PWR & HDD LEDs, PWR button)
Rear panel connectors 1 - 10/100/1000 Mbps Onboard LAN (RJ-45)
8 - USB 2.0
2 - PS/2
1 - Serial (COM)
1 - S/P DIF out (optical)
Physical Form Factor 7 - slot full sized BTX standard (12.6" x 10.5")
The motherboard is a proprietary model, probably made by Dell.
Alright, this may seem like a stupid question, but so far I couldn't find the answer. Does anyone know what motherboard Dell ships in an XPS 410 if you select a Pentium D processor? I know the 410 is made for Core 2 Duo and that the 400 was the one with Pentium D, but the 400 is gone now and I don't know the motherboard in either of them. Help?

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