Motherboard Question

[wlp3333]

I am new to the forums. I am hoping to get some help with my delima. I currently have a Dell Precision 670 and I would like to upgrade the power supply from the stock 500w to something a bit higher. The problem that I am running into is that the motherboard seems to have a 24pin connector AND a 20pin connector. I am trying to find a power supply that would be compatible. Is two motherboard connectors common?

I was planning to buy the following power supply:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817159125

I am not sure if it will work like I think. Thanks in advance people of the Internet.

 

[phil22]

It's not usual to have two main power connectors on retail motherboards, but they do crop up on low-end factory-built computers.

Using only the 20-pin connector feeds less watts to the motherboard. The other 4 pins add three more +5v and one earth.

The current crop of ATX power supplies have a clever "two piece" main connector which can be configured for both 20-pin or 24-pin motherboards by simply sliding the 4-pin connector on or off the 20-pin connector as required.

I suggest you connect all 24-pins to the motherboard to ensure there is no voltage starvation if you upgrade the hardware.

 

[wlp3333]

This is the motherboard in question:
http://www.stuartconnections.com/12804-thickbox/Dell-Precision-670-Dual-Xeon-Mother-System-Board-XC837.jpg
When I got it, both power connectors were populated. Is it safe to run with one or do both have to be pluged into? Thanks for the help.