I have a 450 Watt in ATM that is running a standard NIC a 2.5'' laptop HDD @ 5.4k RPM (3GB/S) w/ a CD/DVD RW Drive and AMD Phenom X4 B55 (Oc'ed AMD Phenom X2 555 Black Edition). I will have a total of 6GB of DDR3 RAM @ 4 Sticks. Also 2 Case fans that are 120 MM (?)
So my question is, can I use this PSU even at the 6770's max power draw.
If not will a 200Watt PSU be good for dedicating it to?
6770's power draw is the same as the 5770's, 108 Watts at maximum. A brand, model number, and number of amps on the +12V rail would help determine if your PSU can handle it. Assuming your power supply can actually deliver 450 Watts, and a decent number of amps on the +12V rail, it should be able to run a 6770 fine, your system probably won't pull much more than 300 Watts with the 6770.
Only 21 Amps on the +12 for the 450 Watt? Obviously it's not a very good PSU or it is quite old, it's effectively only 252 Watts for most of the system, not enough to power your system with the 6770. The secondary PSU you have could just barely run the 6770 on its own, but that would probably not be the greatest idea. You should probably look at getting a decent 400 Watt PSU, that actually has most of its power on the +12V rail, rather than try to run your system off of two separate power supplies.
both the dedicated and main PSU have 12+ Rails (21.0A(Main PSU)) (10.0A(Dedicated)
Are you sure there isn't a 2nd +12v rail on the 450W unit ?? 21A would only be 252Watts (amps x voltage = Watts) which would be pretty low for a 450W unit (unless it is an old PSU from when systems used more +5 and +3 volt connections and less +12v in which case using the 6770 with just it probably would not work well !
The auxillary dedicated PSU with 10A (120W) should be fine to use for the 6 pin connection along with the power (approx. 75W max through the slot) it will pull from the PCI-e slot from the 450W unit - should be fine for the total system set up that way !
@supernova113 -- you forgot the aux unit will only be providing the 6 pin connection - it will still be pulling some power from the 450W using the PCI-e slot of the MOBO -- so that combination should woork just fine !
Still, assuming there is only one +12V rail on the 450 Watt rated at 21 Amps, even if the card only pulls 75 Watts from the slot, that will be cutting it pretty close, the "450 Watt" would be running pretty close to the limit, which isn't a good idea if it is a low quality or old PSU. That, and running a system on 2 PSUs just makes things more complicated and adds another potential point of failure for the system. If he can afford a better PSU, or the 450 Watt turns out to have more than 1 +12V rail, it would be better to run the system with a single power supply.
Edit: That PSU on newegg does have two +12V rails at 22 amps each which would be enough, though I'm not too familiar with the quality of a Raidmax PSU. Does your current PSU have 2 +12V rails? If it does have 2, you probably won't need to upgrade.
Yeah that is an old model PSU that was designed back when video cards and CPUs used a lot less power and systems used more +3 and +5 power overall. Figure it is rated at approx 262Watts on the +3 and +5V lines and 252W on the +12v (and 450Watts combined) which on modern systems is wasting a lot of the potential wattage -- so might be a good idea to get a newer model that provides more +12V Amperage since that 1 is closer to a modern 250W - 300W unit in the +12v Amperage it provides - and as Supernova suggested even combined with the auxillary unit you'd be getting close to the max output under load which might cause stability issues. (especially since you are OCing the CPU !)
Yeah, it looks like it is an older model PSU, with more power on the +5V rail, back when that rail was used more for components. Probably best to look at a new power supply, some good brands would include Antec, Seasonic, or Corsair. You don't need a particularly high powered one, something in the 400 Watt range would power your system with the 6770. I wouldn't recommend trying to use your two PSUs to power your system for reasons stated above.
Looking around newegg I've found a couple of decent quality, that aren't too expensive. Whatever you do, don't go and buy the cheap $20 PSU, you will regret it when it fails to power your system, or blows up in your face.
Since you are overclocking, I would recommend the Antec over the Corsair as it gives you a little more headroom to overclock, you just need to make sure you don't connect everything to the same +12V rail. The wires are usually color coded so, that shouldn't be too difficult.
Not recommended, even with a second PSU helping to power the card, your current PSU probably will not be able to run your system with a 6770, certainly not with your overclok. The Antec PSU I linked to with the two separate +12V rails is the one I was referring to, that one you will have to connect some of your components to one rail, and some to the other, as the individual rails will not support your entire system with a 6770.
Yes, a 600 Watt is way more than enough to power your system with a 6770, you could even add a second 6770 if you wanted to without a problem. You may take a bit of an efficiency hit by buying a PSU with that high a wattage, you'd only be using probably a little over half of those 600 watts, but it isn't a bad choice if you are looking for lots of headroom to overclock or upgrade to a more powerful graphics card down the road.