Effect of using 4 pin instead of 8

[kingfet]

Ok, so I purchased a Gateway FX6800 core i7 system from where I work for very cheap. (we recycle computers). Upon opening it up last night, I noticed that the included power supply only has a 4 pin connection connected to the 8 pin motherboard.

Now I didnt really want to do anything to the system, but that makes me nervous. I can change the power supply if I need to, but do I? What are the possible side effects of only using a 4 pin powersupply? Why would gateway ever do this?

If you need the rest of the specs they are as follows:
I7 920 Processor
ATI 4850
3 gigs DDR3 (hope to move to 6)
Two Sata HD's (hopefully will be 3)
1 Sata DVDRW
Media Card Reader
1 120mm back fan
1 80mm front fan.

The power supply is 500w, should I upgrade it? Especially if I want to add a third HD and three more sticks of memory?

Thanks in advance!

 

[jsc]

The motherboard manuals all say that unless you are running an EE Edition CPU, 4 pins are all you really need.

Another hard drive and more RAM will add only about 25 watts more power consumption.

Depending on the quality of the current PSU, you should be OK. Random reboots during heavy usage will be Nature's way of telling you that you need more power.