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Confused with PSU efficiency and stable Clocks

post #1 of 27
Thread Starter 
So you see,

Im using this PSU calculator -> http://extreme.outervision.com/PSUEngine
and with my desired overclocks its telling me minimum PSU wattage is 372 and recommended 422w.

Im using a ULTRA xfinity 500w PSU, which, for those of you who don't know, is a old PSU from 2006 but has approximately 72-78% efficiency depending on the load (72% at 500w). Well 500 x 0.72 = 360w. Does that mean, my GPU and CPU need 422w but the PSU can only convert 360w?

Im just really confused.

I just ordered....

AMD phenom X4 II 955 - 3.2GHz (desired 3.8GHz OC)
GTX460 768mB OC - MSI Cyclone
4GB PNY DDr3 1600MHz RAM
6 Fans

CURRENT PSU - ULTRA XFINITY ULT-XF500
SPECS: NVIDIA SLI ready, dual 12V rails (18A & 16A) at 384w (384w/12v=32A) Furthermore, its got a 5V and 3V (both 30A) at 160W. Finally a -12V and +5VSB totaling 19.7W

IMPORTANT***** Currently im using a very old Pentium D 820 @ 2.8GHz and OC to a crappy 2.939GHz. However at these Clocks it does not appear to be stable. At 2800.80GHz (OEM) it drops as low as 2800.60 and as high as 2800.91. Overclocking to 2939.23 it can jump 1mhz to 2 mhz.

Does this mean its a crappy PSU for overclocking? Or is this an acceptable range?
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post #2 of 27
no efficiency means to get 500w, it has to take a certain amount from the wall, the more efficient the closer it gets to 500W from the wall or what ever your load is.
I'd try to give you numbers but i suck at math, but if my quick math is correct, lets say you are using a load for 390W with 78% efficiency you will be drawing 500w from the wall.
and i believe you'd be drawing somethign like 680w from the wall at 100% load. The issue here(imo) is that the ultra isn't a good power supply.
post #3 of 27
Efficiency does not effect your components, it refers to how much power your PSU needs from the wall to put out what it has to put out. So if something had 100% efficiency and was putting out 500w, it would take 500w. If it only had 80% efficiency then it would be pulling 600w from the wall, providing system with 500w. So efficiency concerns your electricity bill not your hardware.

edit: Ninjaed^ and to go into farther detail, the reason this happens is due to the conversion of AC to DC. Your wall has AC electricity, your components need nice and steady DC. So your power supply is tasked with converting this AC to DC for your system. It isn't perfect at it tho, so some electricity is lost during conversion. That is what efficiency refers to, how good the transfer of AC to DC is being done.

edit2: To go into your last part.. a stable overclock does not refer to the frequency sticking to one number LOL. Stable means there is no data corruption, no 0s or 1s mixed up. You would get random restarts, BSoDs and the like if it was unstable. Your frequency may balance around abit while in use, that's pretty normal. Really has nothing to do with your powersupply.
Edited by Markisa - 4/25/11 at 2:51pm
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post #4 of 27
you're going to want a new powersupply if you're going Fermi. If you swap that GTX 460 for a 5850 you'll be in the clear

this is a 500watt PSU (googled it)

you'll be running it flat out if you play a game
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post #5 of 27
Thread Starter 
This makes much more sense. My power supply can pull much more than 500w from the wall but in total, it can only deliver 500w to the rig.
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post #6 of 27
Quote:
Originally Posted by Fear of Oneself View Post
you're going to want a new powersupply if you're going Fermi. If you swap that GTX 460 for a 5850 you'll be in the clear

this is a 500watt PSU (googled it)

you'll be running it flat out if you play a game
How ever it's an ultra and not an X3 ultra so it's more then likely overrated and goes out of spec on the ripple.
2JZ Yes... that being said what I state above is probably true.
post #7 of 27
Thread Starter 
Quote:
Originally Posted by Eagle1337 View Post
no efficiency means to get 500w, it has to take a certain amount from the wall, the more efficient the closer it gets to 500W from the wall or what ever your load is.
I'd try to give you numbers but i suck at math, but if my quick math is correct, lets say you are using a load for 390W with 78% efficiency you will be drawing 500w from the wall.
and i believe you'd be drawing somethign like 680w from the wall at 100% load. The issue here(imo) is that the ultra isn't a good power supply.
Whats wrong with ULTRA? Their new X4 modular power supplies seem great, they appear to be a very reputable brand name. The powersupplies, as far as i know, do achieve the advertised efficiencies. Or is this specific ultra not good?
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My System
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CPUMotherboardGraphicsRAM
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120GB Intel SSD Windows 8.1 64bit Viewsonic 27" VX2739wm XFX XTR 750W 
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HAF 912 
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post #8 of 27
Quote:
Originally Posted by 2JZ View Post
Whats wrong with ULTRA? Their new X4 modular power supplies seem great, they appear to be a very reputable brand name. The powersupplies, as far as i know, do achieve the advertised efficiencies. Or is this specific ultra not good?
Ultra's in general are very much not good units. Most of them are made by oems that well aren't known for quality, and it shows when the unit can't do it's rated wattage and goes out of spec on the ripple suppression or just dies.
post #9 of 27
Thread Starter 
Quote:
Originally Posted by Fear of Oneself View Post
you're going to want a new powersupply if you're going Fermi. If you swap that GTX 460 for a 5850 you'll be in the clear

this is a 500watt PSU (googled it)

you'll be running it flat out if you play a game
Sorry if i seem like a newb at computers, last time i updated my rig was 2006 lol and i spent so many hours catching up this past weekend. But what is fermi? my card is advertised as being that, and what does it require for me to have to use fermi?
My System
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My System
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CPUMotherboardGraphicsRAM
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HAF 912 
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post #10 of 27
Quote:
Originally Posted by 2JZ View Post
Sorry if i seem like a newb at computers, last time i updated my rig was 2006 lol and i spent so many hours catching up this past weekend. But what is fermi? my card is advertised as being that, and what does it require for me to have to use fermi?
Fermi is a series of cards by Nvidia. The gtx 4xx and gtx 5xx series of cards are fermi cards.. i'd replace the psu before using your gtx 460 though.. a good 520w psu will be enough.
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