Not a problem.
This is a general view of a SATA -> data cable, and it's respective connector on the motherboard,http://en.wikipedia.org/wiki/File:SATA_ports.jpg
Note the L-shaped opening in the SATA data cable's connector, and matching L-shape on the SATA data connector on the motherboard.
Note also that a SATA data cable's connector has 7-pins
Between it, and a SATA power cable connector, the SATA data cable connector is the smaller of the two.
A SATA power cable has 15-pins,http://www.playtool.com/pages/psuconnectors/connectors.html#sata
Note that it's cable connector opening is also L-shaped.
So is the matching connector on a SATA harddrive, or SATA optical drive. (CD/DVD drive)
A SATA power cable's connector generally has an area on it, that you depress with your thumbnail, and this releases a Lock.
Depress to install, depress to remove.
SATA data cable connector, Or SATA power cable connector; that goes to a Harddrive, or to an Optical Drive, is usually a 90 degree bent elbow.
The straight connector on the cable plugs into the motherboard.
(Can be straight connector on both ends through, but isn't CORRECT)
SATA connectors on motherboard;
IF, this Ebay link selling a Dell Precision T3400 Desktop PC motherboard, is correct, there are;http://www.ebay.com/itm/Dell-TP412-Precision-Workstation-T3400-Socket-775-Motherboard-/360503300257?pt=Motherboards&hash=item53efabd0a1
1) FOUR Black SATA connectors
2) ONE White SATA connector
3) One Blue SATA connector
1 Black SATA connector, and 1 Blue SATA connector, at the bottom of the black Ram Memory slots.
1 White SATA connector, and 3 Black SATA connectors, right next to the where 24-pin ATX main power cable, plugs into the motherboard.
General example of said main power cable,http://www.playtool.com/pages/psuconnectors/connectors.html#atxmain24
(Note* Color of connectors does Not matter )
Originally the Master harddrive, should plug into SATA1 connector on the motherboard.
If you look real close, next to all of those SATA connectors on the motherboard, you may see SATA0, SATA1, SATA2, SATA3, SATA4, and SATA5, printed right next to them on the motherboard.
The beauty of SATA:
DOESN'T MATTER WHERE YOU PLUG IN WHAT, on those SATA connectors.
Use ANY one you wish, and plug whatever SATA device into it, that you wish.
BIOS will find the SATA device.
No matter what SATA connector you plug into, and no matter what SATA device.
What a minute, this news just came in.............
The Blue SATA connector on the motherboard, under the black Ram Memory slots, is SATA0.
The Black SATA connector next to it is SATA1.
If you have SAS harddrives (Serial Attached SCSI), the power cable's connector has a provision, to plug the SATA data cable into it also.
If you do not have that particular SAS power cable it's OK.
You can just use a separate SATA power cable, (90 degree elbow to harddrive/optical drive), and a separate SATA data cable.
For additional questions, or to have me clarify further on anything I have stated above, post in a Comment.