[OddRobb]

I am trying to build a gaming rig, and want to be sure that the PSU that I have in mind will be sufficient for the system i'm trying to build.

here are some of the parts i'm planning on buying:

RAM: 6GB DDR3 http://tinyurl.com/3xlzwyy

GPUs:2 x Asus ATI Radeon HD5770 1 GB DDR5 http://tinyurl.com/34nsdcp

CPU: Intel Core i7 Processor i7-920 2.66GHz 8MBhttp://tinyurl.com/3ys3pqm

Mobo: Asus P6TSE http://tinyurl.com/26qqr6f

HD: Samsung Spinpoint 1TB 7200RPM http://tinyurl.com/2f28bgm

And heres the PSU that I am looking at:
650W 20+4-pin Blue LED Fan ATX PSU http://tinyurl.com/2v6b7f4

I am pretty sure the wattage is enough, but shouldn't I need 2 +12V rails if I plan on using 2 cards in crossfire? I know the PSU i'm looking at is a little cheapo-depot, but i'm on a budget, and it would be GREAT if this thing can handle the setup I want!

[deadlysyn]

First off, to OCF!!

As much as I am sure you aren't going to want to hear this, that PSU will not be enough for any kind of dual card setup. That PSU is rated at around 35A on the 12v rail, which is only 420 watts. The 3.3 and 5 volt rails in current computer systems are practically meaningless. I would highly recommend looking into a PSU from a reputable company, like Corsair, Antec, Seasonic, and the like. You may also want to look into the 850W range if you are wanting to go crossfire. Also, I would recommend getting rid of that PSU, just for the safety of the hardware you are running now. Cheap PSU's are known for killing hardware when they die.

[Jolly-Swagman]

Also that PSU you have linked only has One PCI-e connector too and is very underpowered as deadlysyn has pointed out,
Seeing that the PSU is the heart of your system you would be better going for better as stated reputable company

[OddRobb]

Thanks for the feedback! Very helpful!! But are you sure we are looking at 850W for this system here? That sounds like a bit much, even for a dual card setup. I was looking around other forums and it seems like I shouldnt need any more than 750W for my setup. Ya, I know I should avoid buying the less-known brands of PSU's for cheaper, but I have done so in the past without any problems. But, I will take your word for it and go with the PSU I was looking at originally... This 1 actually has dual 12v rails

http://www.buy.com/prod/a-power-ak-7...210486061.html

Its not necessarily a reputable company, but then again I am willing to take my chances. I really don't want to have to fork out more money than I need to in order to have a functioning system... Of course, I still should to consider any OCing needs though

[I.M.O.G.]

If you haven't seen it Rob, http://jonnyguru.com/

They talk a lot about PSU quality and are pretty down to earth about discussing how and why things fail - they also often mention the true nature of dual rails (what is advertised is often false with PSUs).

[Bobnova]

Here's the thing:
A dodgy PSU can kill the mobo, gpu, other gpu, cpu, ram, hard drive, dvd drive, any anything else plugged into it.

Corsair, Seasonic, or specific other brands or forget it IMO.

[ratbuddy]

Originally Posted by deadlysyn

You may also want to look into the 850W range if you are wanting to go crossfire.

Maybe if he was running 6 of those 5770's. That rig is only gonna be using 325-375 watts fully loaded.

[Trap05]

You need enough wattage, enough PCI-E connectors, and enough quality to get the job done. A Corsair 650tx would be a good choice

[theflyingrat]

Blue Star? A-Power? Ugh. I almost hate to try to find who actually built those things. Rest assured, though, they won't deliver rated power, and they certainly won't provide power within ATX spec at any sort of load whatsoever...

PSUs are NOT a component to cheap out on. Cheap power supplies are simply a cheap, effective way of nuking an entire system's worth of expensive components.

Really, you're running a $270 CPU, $320 worth of video cards, a $180 motherboard, and $150 worth of DDR3... there's absolutely no reason at all to lean all of that on a $40 power supply. It's like throwing a Yugo GV engine in a Bentley Brooklands. It's too much hardware for the core of the system to deal with, especially when that system's power supply is a pile of garbage to begin with.

I would highly, highly encourage the use of a high-quality power supply from a reputable brand (with a good OEMer) in the range of 500-650W. There are lots of great choices out there, and none would eclipse the $100USD mark.

Seasonic SS-650HT
Corsair 550VX
Seasonic S12II-620
Corsair 650TX

All are robust designs that provide stable current, decent efficiency, and more power than you'll need. Not having to upgrade later on if you switch video cards or CPU/motherboard combos, as well as having lots of headroom for overclocking will pay dividends.

[OddRobb]

Alright, alright fine... I'll bite the bullet and play it safe and probably go with that corsair 650tx. Another PSU i'm considering is an Ultra 750W for the same price.

http://www.tigerdirect.com/applicati...y=#ReviewStart

Is ultra a good brand? This unit received great reviews on the website. I figure the extra wattage will be good for oc'ing needs for sure, plus any hardware upgrades in the future. AND its only about $70

[Trap05]

You don't want an Ultra their quality is nowhere near Corsair

[Ancient_1]

Ultra has some decent and some are pretty poor. As far as getting more power with that 750 you wont since it is an older design and only is rated as 45 amps on the 12v rail compared to 52 on the Corsair. Modern systems draw almost all their power from the 12v rail.

You can tell it is an older design from the fact no PFC (it has a switch for the input voltage) and the high 3.3v and 5v capacities. A modern supply like my 750 has the 12v rail rated at 62 amps (744w)and a combined rating of 125 watts on the 3.3v & 5v rails.

[ChanceCoats123]

I have the poor man's version of the LSP (LS 600) in my backup rig (which isn't a very good job as it isn't running yet. ), but either way, I grounded one to my case via a molex connector and it killed itself instead of my parts. I got a new replacement two days later from Ultra and it's been chugging along beautifully. Now I know it isn't a very good choice, which is why I moved to a Kingwin Lazer 750 (little brother of the 1Kw Lazer) and it's been good so far (less than 10 hours of up time though). Anyway, back to my point. The Ultra supplies aren't the greatest, but they are cheaper and you get what you pay for. They do have a lifetime warranty and Ultra has grade A+++ customer support. I would use them for a cheap rig, but not with a $800+ rig.