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GPU for 375W PSU ?

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February 22, 2007 10:38:50 AM

Hi,

My computer specs are below:
Intel Pentium D 930
2GB RAM
2x 250 GB Hard Drives in RAID 0 Array
Geforce 7300LE
375 W PSU with 35A on dual-12V rails

I am thinking of upgrading the graphics card - one that would be good for Windows Vista. Ideally, it should be under £100. I bought a 7600GT and tried it out on my system - but my PSU could not support it and I had rendering errors. So I returned the 7600GT. Now, I would like a graphics card that would run stable on my 375W PSU. I have no preference of ATI or Nvidia.

I was thinking an X1600 or X1650 based card (I heard these only require 300W) ?

Cheers :D 

More about : gpu 375w psu

February 22, 2007 10:53:51 AM

The total wattage of a psu doesnt matter, its the number of amps on the +12v rail. You say it has 35a, but thats impossible, you would need a psu with atleast 420w on the +12v rail to have that many amps. Whats the make and model of your psu?
February 22, 2007 11:03:42 AM

Quote:
The total wattage of a psu doesnt matter, its the number of amps on the +12v rail. You say it has 35a, but thats impossible, you would need a psu with atleast 420w on the +12v rail to have that many amps. Whats the make and model of your psu?


My mistake. I just had a look at the PSU. It's a Dell model and it says:

+12VA - 17A
+12VB - 12A
Related resources
February 22, 2007 11:14:50 AM

Thanks. What about a 7600GS - will that work on this PSU ?
It only consumes a little more power than my current 7300LE.
February 22, 2007 11:21:29 AM

Ok. Thanks for the help. Perhaps the 7300GT ? What about that ? I really want to run Vista on this system (I'm not looking to really play games though). So will the 7300GT be much better than my current 7300LE ?
February 22, 2007 11:27:03 AM

Thanks a lot for your help :D 
a c 243 ) Power supply
a b U Graphics card
February 22, 2007 11:45:54 AM

Your psu has a combined output of 30 amps on the +12 volt rails.
I use a 7900 GTO in my XPS 410 with stock 375w psu, others are using the 8800GTS and GTX with the same psu.Check the Dell forums.
If a 7600 GT won't work,then maybe the psu is going bad.
a c 243 ) Power supply
a b U Graphics card
February 22, 2007 12:53:40 PM

No 375W PSU will ever be able to supply more then abour 28A.
Dell understates the wattage in an attempt to keep people from overloading thier system, on the retail market the 375 watt Dell would be labeled as a 480 watt unit.

The OP was adding the 2 +12v rqails together. Finding total amperage dosn't work like that.
I realize that,which is why I posted the stated combined output, as per the label.

The amps per rail are the max that rail can handle without failing. Not the max amps being supplied to that rail.
It has been stated that the fail point of the +12 volt rails on this psu is 19 amps.

Read the PSU 101 link in my sig to learn more.
I have on several occasions, and now have the opportunity to thank you for providing it. :) 

Regardless of any of this the 7600 GT is certainly not to much for the Dell 375w psu to handle.I'm guessing that the OP has an XPS 400, which during it's time was offered with the X1900 card which is much more power hungry than a 7600GT.
February 23, 2007 1:16:42 AM

That is far from enough. Dell tends to skimp on their PSUs a little too much IMHO.

Quote:
A 350W PCI Express compliant system power supply (with 12V current rating of 20A or more)


and that's a pretty conservative rating. Can't imagine how a PSU like that felt powering an X1900..
a c 243 ) Power supply
a b U Graphics card
February 23, 2007 1:52:22 AM

Check out the Dell forums , the Dell 375 watt psu is being used to power the 8800 GTX cards.
February 23, 2007 2:14:07 AM

It's not a matter of whether or not it can boot up with it. It's a matter of not stressing the PSU. And if you are going to be gaming on the 8800GTX or an X1900 then you will stress that 375W 19A or 20A PSU as it is far below the recommended.
February 23, 2007 2:18:31 AM

I just installed a 7600GS in my computer . I have a 300 watt power supply, I have also overclocked the core processor from 450 to 490Mhz. The memory from 400 to 450Mhz. I have had no problems so far and the highest temp I have logged is 49C. I ran 3D mark 2001 3 times andscored 17161 and have been playing the Chronicals of Narnia game for over an hour with no lockups or anything.
a c 243 ) Power supply
a b U Graphics card
February 23, 2007 3:50:48 AM

Well the psu is rated for 30 amps not 19 or 20, and I can't believe that they are using the card for just web browsing.
February 23, 2007 5:35:02 AM

Quote:
Dell understates the wattage in an attempt to keep people from overloading thier system, on the retail market the 375 watt Dell would be labeled as a 480 watt unit.


Is that true? it would be quite useful to know that 8O
I got a dell xps 400/9150 and I am running a BFG 7800 OC wich requires a minimum 400W system power supply (with 12V current rating of 26A or more)
but I have never had a problem with it....I have even overclock the card and it works like a charm.

this info its quite usefull now I can get a 8800 gt :wink:

February 23, 2007 5:38:32 AM

Did you read Mpilchfamily's post? You can't just add up the amps on both +12V rails. You have to take the wattage on the +12V rail (I'm not sure how much it is but it is certainly not 360W as that would be 96 percent of the PSUs total output which I have never seen on any PSU, my corsair which is a high quality unit only has about 93% of the total watage on the +12V rail which in itself is very high). As Mpilch said its probably closer to 20A max output. Trust me (and others will back me up on this) Dell doesn't put very good PSUs in their systems. It's not going to explode or anything... but it will reduce the lifetime of the system significantly.
a c 243 ) Power supply
a b U Graphics card
February 23, 2007 11:33:04 AM

Since you own a Dell, why don't you go over to the Dell forums and have a look at what is being written there ?
My 7900 GTO has the same power recommendations as your 7800 and they said it wouldn't work either although Dell offered the machine with the 7950 GX2, which has greater power requirements.

Valtiel, you're stuck on the 375 number, in my previous post I stated that Dell understates the wattage of thier psu in an attempt to keep people from overloading their machines. If the psu couldn't handle it there would probably be posts with people crying that they burned up thier machine, but that's not the case. And Dell would not have offered the more powerful cards, since if it did cause a problem they would have to take care of it.
February 23, 2007 4:29:07 PM

:? Is there a way that I can test my psu and know if its capable of handleling a 8800 gt? and yeah I have read all the post on the DELL support forum and theres a lot of people who say that it works , but I am just wanna be sure. :roll:

and another thing I completle forgot that I can use 667mhz ram is there a big diference between the 533mhz to those?I mean is it worth getting?

February 24, 2007 12:40:56 AM

No, I'm stuck on the 20A rating. 20A is not enough. Show me and/or prove to me that they understated the amperage and then I'll stop ripping on Dell.
February 24, 2007 1:46:28 AM

My last machine was a Dell 9100 with the afore-mentioned 375w power supply. Mine said 18/16 amps for the a/b 12v rails on the label. I ran a Pentium 940 with an overclocked 7900gt on that PSU with no problems for eight months before I gave the system to my brother and built my own.

Just my 2 cents...
a b U Graphics card
February 24, 2007 2:21:21 AM

yeah some people think dell psu,s are crap.
but they are wrong!!
February 24, 2007 2:59:59 AM

FX5200!!!!! FTW!!!!!!11111

:lol:  :lol:  :lol: 

My last sys, 805D @ 3.6Ghz and 6800GS OC. I THINK that ran on something like a 400W psu?
Having said that... why cant u get a new psu? $? U can look in local papers/online/friends get a 2nd hand 1. Even if its 450W it should be good. I got a new 650W, was like $100USD.
February 24, 2007 7:39:53 AM

Fine fine fine, I'm wrong. I stepped out of line. If it can run it, it can run it. What do I know anyway... :roll:
a c 243 ) Power supply
a b U Graphics card
February 24, 2007 12:23:17 PM

Valtiel, the amperage is rated at 30 not 20
+12 volt A 18 amps
+12 volt B 18 amps
Combined output 30 amps
As per the label
The wattage is what I said has been understated.
a b U Graphics card
February 24, 2007 1:04:09 PM

the dell psu,s are better than peoople give them credit for.
but they arent designed to be ovewrloaded..

if dell and gateway put cheap quality psu,s in all of the comp,s
they sell, they would be in big trouble..

think about it.
when a psu fails there is a good chance it can fry other things too.

dell and gateway dont want psu,s that
committ suicide and homicide :lol: 
February 24, 2007 4:10:05 PM

Quote:
dell and gateway dont want psu,s that
committ suicide and homicide


good one :lol: 

Anyway I opening my dell today and taking a picture of the power supply info , I hope it helps.

ok here it is:


February 25, 2007 1:45:11 AM

ok thanks, now I'm convinced and a great deal less worried for your and the OP's system.
February 25, 2007 5:07:02 AM

As mentioned by DellUser, Dell is conservative with their PSU ratings. I have not looked at the PSUs in the BTX cases, but just a year ago when Dell still had the ATX designs, all of their power supplies were rated as MAX SUSTAINABLE LOAD, meaning the rated amps on each rail are real-world ratings, not the "Peak power" amps found on almost all aftermarket PSUs.

I run my Pentium D 805 system on the original Dell 250 watt PSU.
a b U Graphics card
February 25, 2007 12:00:42 PM

Quote:
all of their power supplies were rated as MAX SUSTAINABLE LOAD, meaning the rated amps on each rail are real-world ratings, not the "Peak power" amps found on almost all aftermarket PSUs.


thats what i have been meaning to say :lol: 

yours is the best explanaition yet :wink:
!