Nov 1, 2010

Im planning on upgrading my current system (i5 760@3.5ghz, 1gb XFX6850,8gbDDR3@1600,Ultra LSP550 550-Watt PSU) to sport a second 6850 in CF. I was wondering if I needed to upgrade my PSU to accomodate this, I know the 6850's are know for low power consumption but I dont know how much of a difference it makes.
Thanks ahead of time.

The problem with that LSP PSU is that it isn't of high quality.It says it delivers 550watts but it actually only delivers somewhere around 360watts.The Seasonic PSU I linked is able to supply 480watts.That PSU is a true quality PSU and it is capable of delivering what it says it can.
^+[as many as necessary]. Your Ultra PSU-shaped object has a liar label on it. A quality 500W-550W PSU will have no problem with a pair of those cards. The only correction I'd make is that you shouldn't need any molex adapters, as each of those cards only needs one PCIE power adapter. This also tells you each card running flat out could not possibly need more than 150W; so 300W for the pair, and less than 200W for the balance of your system (unless you have a lot of drives).
A quick reference would be to look at how many amps are on the +12/v rail(s).The +12/v rail powers almost everything within the PC.
On the back of the PSU is a chart that will list the max supported wattage for the +12/v rail(s).Although some companies don't even include the max wattage supported because they know it's that bad.

You can also try to look up the PSU to see if their are reviews on it.



Yes - read accurate, objective PSU reviews at reputable sites such as or on the EXACT model PSU that you are interested in as some brands have good and poor quality PSUs.

You can also get an accurate rating of how much PSU power is required for your current or future system at the PSU calculator link below. Once you know the total PSU watts required then you need to confirm that the 12v rail has enough amps. to support your Vid card(s) and the rest of the PC system.

There are several websites that show the Vid card power consumption in watts. Divide the watts by 12 to determine the amps. required on the 12v rail(s). Add 15 amps for the rest of the PC on the 12v rail and you now know the Minimum total 12v rail amps required under full load. It's best to have at least 5-10 amps. reserve on the 12v rail available under full load so the PSU is not loaded to 100%.

yes, only buy, Antec, Corsair, XFX, Seasonic, PC power and cooling and you will get a PSU without a liar label. Ultra get some good reviews sometimes, but they are still cheap crap despite this and have a high failure rate. If its not one of the brands i listed above you should find a review of a psu before you buy, a proper review where they disect it, load, ripple, noise tests etc.