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Single Rail vs. Multi Rail *Explained* - Page 11

post #101 of 118
Thread Starter 
It's not cheap. In fact it's very expensive to manufacture. It was just easier to design that way back in 2007, when CWT realized that everyone else was making 1kW+ power supplies and they hadn't done the research on transformer technology needed to match those designs. So they "cheated" and put two PSUs on one PCB, giving them a serviceable 1kW+ design in a minimum amount of time, and it actually happened to outperform much of the competition at the time too. It's a little long in the tooth now, but it's still a quality power supply and ridiculously overkill for your needs. It should do fine.
post #102 of 118
Thx for clearing it up & cheers for the quick response.

Still one of the best Threads out there....thumb.gif
post #103 of 118
Quote:
Originally Posted by Phaedrus2129 View Post

.......and ridiculously overkill for your needs.......

Back then, I thought PSU's loose some of thier output power over the years(10% every year but no more than 50% overall) & I needed mine to last for 5+ years for all my upgrades. I also thought they worked best @ 50% load (I think my 2x275GTXrig consumed 750watts so I went looking for +1.5kwatt PSU's) .
That's why I got the biggest I could find .....back then.

Is that true btw, time does damage the PSU's power output? what about ripples, do they increase as the PSU ages?

Cheers
Edited by eXXon - 9/21/12 at 4:55pm
post #104 of 118
Thread Starter 
A quality PSU generally does not degrade significantly over its intended lifetime (warranty length basically). Ripple might drift up 10-20mV over the years and it might develop a quirk or two, but a quality PSU should last a long time.

Now, if the manufacturer uses cheaper capacitors than are necessary to last out the warranty period, you might get issues. Like if a company uses Taiwanese capacitors in a PSU with a 5+ year warranty, or if Chinese capacitors are used in a PSU with a 3+ year warranty, or if Fuhjyyu or ChengX capacitors are used period. Then ripple might increase by 20-50mV and if the primary capacitors degrade the total output capability could decrease as well.

However, your PSU and most PSUs recommended on Overclock.net are not subject to that type of degradation and should maintain acceptable performance throughout their lifetime.
post #105 of 118
Ok, lets say a graphics cards requires 30A on the +12v rail. Would it be better to have a single 30A rail or two 15A rails?
post #106 of 118
Thread Starter 
Quote:
Originally Posted by bengal View Post

Ok, lets say a graphics cards requires 30A on the +12v rail. Would it be better to have a single 30A rail or two 15A rails?


Irrelevant. The quality of the power supply matters much, much more than what rail configuration it has.
post #107 of 118
Quote:
Originally Posted by Phaedrus2129 View Post

Irrelevant. The quality of the power supply matters much, much more than what rail configuration it has.

So what you are saying is it doesn't matter? Either of the PSUs can run the 30A card perfectly fine?
post #108 of 118
Quote:
Originally Posted by bengal View Post

Quote:
Originally Posted by Phaedrus2129 View Post

Irrelevant. The quality of the power supply matters much, much more than what rail configuration it has.

So what you are saying is it doesn't matter? Either of the PSUs can run the 30A card perfectly fine?

It's just a matter of safety trip points, where the cables are hooked up. If they're set stupidly, then you can have limits reached while running a legitimate, intended load, resulting in unintended shutdowns (false alarms, pretty much). Every multi-rail PSU in modern times has sensible trip points and rail configurations, and you'll never trip the protections unless there's actually a problem like a short circuit. If you have fewer of them (single rail), then they might not catch an actual problem that another design could have, like an unintended short circuit. There's no difference in other electronics and power output quality or reliability.

Depending on the specifics of your hypothetical example, like what the limits are set to and which wires are distributed to which rails, the one with two 15A rails may trip the safety protection feature (during normal operation, so not desired behavior) and thus not work. That's because your hypothetical example is not realistic.
post #109 of 118
Quote:
Originally Posted by bengal View Post

So what you are saying is it doesn't matter? Either of the PSUs can run the 30A card perfectly fine?

Dude, Rail is not power. Its like a fuse that cuts off power when its maximum is reached....and it shouldn't/can't determine the quality of the PSU.
post #110 of 118
Mr. Phaedrus2129

Is this PSU recommended ? for 169$
http://www.amazon.com/gp/product/B00607JL5C/ref=s9_simh_gw_p147_d0_i2?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-2&pf_rd_r=138ZRAA4KXR8FPVXWD2B&pf_rd_t=101&pf_rd_p=1389517282&pf_rd_i=507846

Can I also ask about your thoughts on EVGA's 1500 PSU with thier funky software?
EDIT: they implemented 'Single & Multi' rail design in it which is controlled by the software.
Edited by eXXon - 10/12/12 at 3:27pm
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