Do I Need a Better Power Supply?

The 400 watts is also to include low end budget power supplies. It applies to the full system not just the card. The card takes at most 64 watts as per ATI's own website.

http://www.amd.com/us/products/desktop/graphics/ati-rad...

This said, what is the 12volt amperage on that power supply?
What other hardware is in that system?

Just a example, i have a
H55N USB3
I5 750
AMD 5770
2 sticks of DDR3 1333
1 slimline DVD
1 Hard drive(used to have 2 but was too loud)
All this is on a 300 watt power supply.

A 5670 only needs about 60 watts. So your PSU is certainly more than adequate.

That 400 watt recommendation is for a complete "typical" system.

As long as your system is running satisfactorily, a larger PSU will not improve performance.

Along with the 5670 I have:
Intel C2D E6300
4GB DDR2 RAM (4x1GB)
250GB 7200RPM Primary Disk
2TB 5400 RPM Secondary Disk
Stock Mobo
Lightscribe DVD

If you're fine on a 300W supply than I should be fine...?  
seems like the CompUSA employee was insanely wrong by recommending me a 600W...

I think yours system should be fine, but check the label to see how many 12volt amps there are.

It is important to know that my system is a sff system optimized for low power consumption.

I am not saying there is not a use for having a bigger power supply. Less stress on the power supply and better efficiency if you use 50% of the total power.

My main system has an 850 watt psu. Overkill for a system that has trouble breaking 300-350 watts(I7 920 @ 3.5 + 5870 + 5 hard drives and 6 sticks of memory.....see a trend here it takes lots of hardware to NEED 600 watts).

If it ain't broke, don't fix it.............

But, Sorry, a 250watt supply is NOT adequate for a system with any add in graphics card. Also, there really are no "good" 250watt supplies made as they are all design for low end low power systems without add in graphics cards......so don't worry about looking up the power on 12volt rails. And after they are a few years old, NO supply will output it's original rated power due to capacitor/component aging.

This site recommends a 400watt supply for your card. That's fine from most entry level GPUs & systems. You can buy a 400watt supply from a good brand like Corsair on sale for about $20 (CX series...)

http://www.realhardtechx.com/index_archivos/Page362.htm

Best answer selected by barronlroth.

This topic has been closed by Maziar