x1950xtx PSU Requirements

[Professor Frink]

I've just received a Intel Core2Duo 2.4, Sapphire x1950xtx, 2x1Gb Corsair TwinX XMS2 DDR2 pc6400, couple of 250Gb IBMs; for raid, Abit AW9D-Max, Creative X-Fi Extreme and a Antec Sonata II with a 450Watt SmartPower 2.0.

I'm going to build it tomorrow but worried after reading on the internet that the PSU might not be up to scratch. I've read that I will need at least a 450W PSU with 30+ amps on the 12V rails. After looking at the specs on the SmartPower it has 2x 12V rails which are 15A and 17A (If I use this PSU which one should I use on mobo?).

Should I just build it and see if it works (I was thinking about buying a new PSU in a month or so when I get some better CPU cooling, not much cash left over so have to stick with no overclocking because of retail CPU cooler atm) or should I order a new PSU now and wait off building until I have that? If the later can anyone recommend a good £85-95 PSU (I will not buy a Hiper).

Thanks for any help on the subject.

[Clunk]

A 600w model should be fine for that setup and give you some room for upgrades later on. Seasonic are a safe bet.

[Professor Frink]

Any thoughts on building the system now or waiting until I can get another PSU? Will the 450W be okay for a few weeks to a month until I have the cash for a Seasonic, Enermax, Antec. etc?

[Clunk]

Im not familiar with that PSU, but if its half decent, but underpowered, then you will possibly just have reliability issues, if its a cheapo one, you could fry it

[Blitzen]

That PSU should be fine without an overclock.
Upgrade soon and go for the Corsair 520W or 620W. Both great !!!

GL

[Professor Frink]

I've been looking at PSU on the internet, plus Power Supply Calculator (Says 361W should be enough but I'm not sure how reliable it is) and I've noticed that quite a few high ish end PSU come with 3x 12V rails that pump about 18A each. I presume these are for people SLI/Crossfiring, giving the mobo and each graphics card a supply but does the extra couple of amps make the difference? The Antec SmartPower 2 450W covers the recommendations and I know how companies make the recommendations a lot higher than they need to, to stop people complaining/ suing them. I think it should do for a while until I can set aside £90 for a new PSU.

I looked at my old Enermax that I use for my storage PC and that has one 12V rail with 33 amps.

[oralpain]

No way in hell is an X1950XTX going to draw more than 8-10 amps on the 12v rail. If your 450 watt PSU is of good quality it will be more than enough for the equipment you have listed.

I have a 420 watt enermax with comparable 12v rails, and I am running a 7900GS with a 40% overclock and 33% overvolt (uses about exactly as much power as a 7900GTX now), and I have zero stability problems.

Edit: The single 33A rail may be a better choice.

[Professor Frink]

Thanks for all the advise, I feel a lot better about using the Antec 450W now.

[oralpain]

Try it out. If you can, use a multimeter to measure the +12v when the system is under high load (ie middle of a 3dmark run), while the room is warm. If the voltages look fine, and everything is stable, you should be ok.

[Couger]

No way in hell is an X1950XTX going to draw more than 8-10 amps on the 12v rail. If your 450 watt PSU is of good quality it will be more than enough for the equipment you have listed.

I have a 420 watt enermax with comparable 12v rails, and I am running a 7900GS with a 40% overclock and 33% overvolt (uses about exactly as much power as a 7900GTX now), and I have zero stability problems.

Edit: The single 33A rail may be a better choice.

Dont be so sure my friend even my X1900xt draws 15 -25 amps under load

[oralpain]

Impossible, unless you have one incredible overclock.

A 1900XT does not use 180-300 watts. A 8800GTX doesn't even reach that. Many crossfire certified PSUs don't reach over 18A on each 12v rail, and that ratting usually a peak power, not continuous.

http://www.xbitlabs.com/articles/vid...ion2006_4.html

The X1900XT is 108 watts, while the XTX is 120. The 1950XTX is really different only in memory, when it comes to power consuption, so we can figure 130 watts, tops. If all of this power comes from the +12v, that is still less than 11A.

The second 12v rail on frink's 450watt PSU is ratted for 17A, under the top load conditions, I figure that rail will face 14A of load, he's cutting it really close, but it should be sufficent. The first rail will be underloaded (the core 2 chip and the few other components on rail 1 will draw 7 amps at the most), which is why I stated the other PSU with 33A on a single rail would probably be a better choice, as I would rather put 21A on a 33A rail than 14A on a 17A rail.

Then again, it's likely that the 450 antec is not two true rails, but an overcurrent limiter on each pseudo rail, so all should be fine.

[Couger]

well then ATI tool which is where i got my results from is infact incorrect i retract my statement after reading into it sry oralpain

How ever ATI does infact recommend a min of a 450 watt psu with the around 20 amps on each rail to allow enough power for other devices it seem the only time 20 amps will be drawn is in crossfire mode

cheers cougs

[Professor Frink]

Seems the PSU is not upto scratch. The system will only power-up for about 30 seconds at most. All fans spin and nothing is getting hot, so it must be the PSU. Will have to get a new one 550W+.

So back to the title, what PSU would you recommend?

[Clunk]

A 600w model should be fine for that setup and give you some room for upgrades later on. Seasonic are a safe bet.

S12, Corsair 620w, Enermax Liberty 620w perhaps.

[Professor Frink]

What's the general consensus about Seasonic?

[SiM]

Seasonic are regarded as good, silent PSU - You could probably get slightly better ones in same price range but they will be louder. If noise is a concern go for seasonic