Dell XPS DCDR01 Owner's Manual page 130

Memory
Memory module connector
Memory module capacities
Memory type
Minimum memory
Maximum memory
Expansion Bus
Bus type
PCI (SLOT5 and SLOT6)
connector
connector size
connector data width (maximum)
bus speed
PCI Express (SLOT2)
connector
connector size
connector data width (maximum)
Bus throughput
PCI Express (SLOT3)
connector
connector size
connector data width (maximum)
PCI Express (SLOT1 and SLOT4)
connector
connector size
connector data width (maximum)
130
Specifications
four user-accessible DDR2 sockets
128, 256, 512 MB, 1 GB, or 2 GB non-ECC
800 and 667-MHz DDR2 unbuffered
SDRAM; SLI memory
1 GB
8 GB
PCI Express x1, x8, and x16
PCI 32-bit
two
124 pins
32 bits
33 MHz
one x1
36 pins
one PCI Express lane
x1 slot bidirectional speed — 2.5 Gbps
one x8
98 pins
1 PCI Express lane
two x16
164 pins
8 PCI Express lanes
NOTE:
SLOT 1 is the primary GFX slot and
SLOT 4 is the secondary GFX slot.