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Please settle an argument - Asaka 460W good enough for a 8800GT ?

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January 11, 2008 1:04:46 PM


Looking for some knowledgeable advice :) 

My setup..

Intel Core2 Duo E6400
Gigabyte 965P-DS3
4 X 1Gb DDR2 RAM
4 X SATA HDD
1 X DVDRW
4 X 120mm CASE FANS
1 X 4 port PCI USB Hub
2 X USB powered addons (mouse + wireless dongle)

I'm looking to buy an XFX 512mb 8800GT AlphaDog Extreme (OCed to 640MHz) card and need to know if my PSU - an Akasa (Enhance) 460W UQuiet model - will be good enough for this or will I need an upgrade?

There's a photo of the PSU specs label here > http://www.extremeoverclocking.com/reviews/cases/Akasa-460w-PSU_2.html

I posted on a different forum and the thread became an argument between two experienced members. One saying that my PSU is fine for a 8800GT and one saying it isn't as the current on the 12V would be too low (?).

Help!

:whistle: 
January 11, 2008 1:16:22 PM

Hmm im no professional but i delt with this topic before.... You should never get anything equal to what you think is ENOUGH power.. You will lose life from the PS and possibly not even enough power will hurt something prolong...... You should atleast get a 600 or more and why not get more??? If you plan to upgrade later in the future then the PS will be a problem... I suggest getting a higher output PS..... 4x120mm fans wow all that on a 460w not good man.... also a video card like this would require 80-130w alone....
January 11, 2008 1:16:55 PM

You only have 14A and 15A on your +12v1 and +12v2. That's pretty low... you may be cutting it pretty close.
January 11, 2008 1:53:29 PM

Thanks tgstyle but that just calculates Wattage. It's current I'm concerned about.
January 11, 2008 1:57:10 PM

Ok so here is a breakdown of what you have

460w max power
210w for 3v+5v
250w for 12v

dual 12v rails rated at 14a and 15a (doesnt tell you much really)

250w/12v = 20.8333a max on a single 12v rail.
the 8800gt is rated for a minimum of 26a.

now is the east part!

20.8333a < 26a

most likely will not be enough power., especially with all of those peripherals.
January 11, 2008 2:15:27 PM

yeah, man... that's shaving it awfully close. the 12v rails are not going to stack without loss, so 14a+15a doesn't equal out to 29a, it's going to be a little lower. but with a little work you can figure out just how much 12v power you're going to need. here's how.... find all of the 12v and wattage requirements you can for all of your parts. or at least something in the ball park. then use this equation to figure it out. currant x voltage = power
(I) x (v) = (w)

then make sure you're ABOVE that.

i think i saw something on newegg.com that said the 8800gt's require 22amp 12v rails? which is prolly an estimate to run that including the power consumption of most basic computers. i would try to hit at least 500 watts total, with a little more juice on the 12v rail/rails.

but like thoes above me, i'm not exactly an expert. but that equation has served me well in the past, and is pretty simple provided you can find the power requirements for your other parts.

ps: not to mention the fact that as time goes by your psu will slowly degrade and it's ability to put out max power will decline. if you plan on keeping the rig for a while, get some extra power to avoid future psu failure.
January 11, 2008 2:19:47 PM

Its even a Pax Power supply. Wow.


Because P is futher along the alphabet than M, its more powerful.

:pt1cable: 
January 11, 2008 2:27:42 PM

in the end, i guess you could always just try it and make sure you have backup dough in case you need a better psu.
January 11, 2008 2:28:35 PM

Well hello nacho, long time no see!!! And yes, we know your no expert.

I already did the calculations for the 12v rail in the above post.

nachowarrior said:
in the end, i guess you could always just try it and make sure you have backup dough in case you need a better psu.


I, and everyone else on this forum would strongly advise against that.
January 11, 2008 2:35:22 PM

skittle said:
Ok so here is a breakdown of what you have

460w max power
210w for 3v+5v
250w for 12v

dual 12v rails rated at 14a and 15a (doesnt tell you much really)

250w/12v = 20.8333a max on a single 12v rail.
the 8800gt is rated for a minimum of 26a.

now is the east part!

20.8333a < 26a

most likely will not be enough power., especially with all of those peripherals.




Many seem to be confused about the power consumption of graphics cards. The nVidia recommended PSU requirements are for the entire system, not just the graphics card. The 8800gt under full load pulls around 78W, or 6.5A.

http://www.atomicmpc.com.au/forums.asp?s=2&c=7&t=9354&p...

The OP's system likely doesn't pull more than 225W from the wall under load. The 12V rail output would likely be sufficient (running CPU and graphics on separate rails). I would personally opt for a better brand and better 12V output to be stable and more efficient.
January 11, 2008 2:43:36 PM

interesting to say the least!!! 78w at full load. I didn't believe it until I read the xbit analysis.
Fact still remains that the quality of that PSU is questionable, and he still has a maximum of ~21a on the 12v rail.

Im not sure I would be comfortable letting my nice expensive system be run off of that measly little thing.
January 11, 2008 3:08:52 PM

skittle said:
interesting to say the least!!! 78w at full load. I didn't believe it until I read the xbit analysis.
Fact still remains that the quality of that PSU is questionable, and he still has a maximum of ~21a on the 12v rail.

Im not sure I would be comfortable letting my nice expensive system be run off of that measly little thing.


I agree. I good powersupply is like insurance. Always worth the extra investment. Clean power can go a long way in making a system more stable.
January 11, 2008 3:13:11 PM

rallyimprezive said:
I agree. I good powersupply is like insurance. Always worth the extra investment. Clean power can go a long way in making a system more stable.


Stability, efficiency, and life of the PSU (and system for that matter) are factors that must be considered right along with power and amperage output.
January 11, 2008 3:29:10 PM

Thanks all.

I think I'll get a Corsair HX-520W to replace it.
January 11, 2008 3:53:46 PM

I recently got an electrical use meter and I was curious about how much power computers actually use. So I went and measured the highest powered rig that I have access to, a friends who I helped build this summer.

It's stats

Gigabyte DS3-P35
Q6600
eVGA 8800GTX
8 GB RAM
Plus optical, etc

He's running it all on an Enermax Liberty somewhere in the neighborhood of 700 Watts.

So, I was curious to see the max power draw while the computer was under load. I figured Crysis would be a good program to heat it up a bit. I was a little surprised to find that Crysis with everything cranked up as high as you can on a single 8800GTX only draws about 260 Watts. At Idle the system draws 125-160. This is measured at the wall so it should also take any inefficiencies in the PSU into account

What I have taken away from this test, as well as advice here on the Forums, is that - as in most other aspects of life - when it comes to Power Supplies, quality beats quantity. In other words, just buy a good brand and don't worry so much about the watts
!