Dell Precision 490 - Manual (Page 7)

System Board Components
1 power supply
2 system board
3 memory fan
4 front fan
5 card fan
1 primary processor connector
(CPU_0) 15 Flexbay connector (USB)
2 secondary processor connector
(CPU_1) 16 SATA connectors (SATA_2, SATA_1,
SATA_0)
3 front fan connector
(FAN_FRONT) 17 floppy drive (DSKT)
4 card cage fan (FAN_CCAG) 18 front panel connector
(FRONTPANEL)
5 internal speaker connector 19 PCI-X card slot (SLOT6_PCIX)