# PSU upgrade for Dell Dimension 8400?



## agcereniv (Oct 21, 2004)

Hey everyone - 

My dad is trying to upgrade his Dell Dimension 8400 and has purchased a nice graphics card, etc - now he must upgrade the PSU from 350W to 450W or 500W.

I have read the sticky and realize that by what it says, Dell stopped using proprietary PSUs and we should be able to purchase another, non-Dell upgrade.

But, I want to make sure before having him buy one and plug it in and *pzzzzzttt* occurs and his comp is fried.

Please advise on what can be done, or even on specific PSU's to use.

Thanks!


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## UncleMacro (Jan 26, 2005)

The Dimension 8400 uses a standard ATX power supply with a 24 pin main ATX connector and a 4 pin 12 volt connector for your CPU. I checked the pinouts just to make sure and they're plain old standard ATX. But while looking at the power supply specs on this page I noticed a weird non-standard connector coming from the power supply. It's a 6 pin connector called "DC Power Connector P4". A standard power supply won't have one of those. It doesn't go in the motherboard so it might be used for some kind of case front panel stuff. I'd open your machine up and see if that connector is plugged into anything. If so, then you're going to have to chase down a power supply designed specifically for that computer or find an adapter cable to provide that power.

The other thing worth mentioning is that, depending on the video card, you may be able to get by with your existing power supply. The supplies used by OEMs like Dell can usually deliver their claimed wattage and video card makers tend to be very conservative when specifying what kind of power supply that need (it saves them a lot of tech support problems). It's better to have some wattage headroom when it comes to power supplies but you could just give it a try with the one that's already in the computer. It should work just fine as long as you're not in 3D mode because video cards only get near their peak power consumption in 3D mode. If it shuts off or gets flakey in 3D mode then you'll have to replace it.


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## agcereniv (Oct 21, 2004)

*You guys rock!*

Thanks so much - you guys told me in 30 min more than 2 hours on the phone with Dell. Also, you gave me good information, not the crap they did on the phone (why, yes, it is still a proprietary PSU, and, no, we don't offer any more powerful ones for that model).

I'll look into that P4 connector.

The GPU is a GeForce 7900GTO, with a recommendation of 450W (+12v 22a rail) power. I ran a calculation of his current power consumption and still had quite a bit of room even with the 350W, but we will see what happens.

In either case, it's good to know that an upgrade could be bought outside of Dell.

*Dad - your homework is to find what the P4 connector plugs into - or, take digital photos and send them to me so I can*


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## UncleMacro (Jan 26, 2005)

> The GPU is a GeForce 7900GTO


In real life, that video card uses about 80 watts at peak loads so it's a pretty large power consumer compared to most video cards. Nonetheless, I'd just go ahead and try it with your existing 350 watt PSU and see if it has problems in 3D mode before worrying about swapping power supplies. But if you'd like to play it safe, a higher wattage PSU would be a good idea.


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## linderman (May 20, 2005)

Hello:


I recently worked on a computer that had that "weird" connector I installed a new Antec SP-500 in it and called antec about the missing 6 pin connector

they furnished me an adapter for $15.00 with shipping that used two four pins molex plugs to make the conversion wasnt any big thing

I can also instruct you how to save the plug you have from the Dell and make one from a new PSU its childs play

best to give us a picture of it if possible and verify that your system is indeed using it.

BTW: I will be shocked if you system doesnt show problems after upgrading to a 7900GT especially if you previously had intergrated grafix.

enjoy

I personally would opt for the Antec True Power 2 at newegg.com for about $89.00

many times by the time you figure out there is a problem you have messed up a hard drive or ram sticks its best to Buy before you FRY


I dont know anyone that buys a 7900 sereis card that doesnt have some intense gaming in store for the upgraded box


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## jflan (May 29, 2005)

They're pricey, but the Holidays are almost here, so what the heck !
http://www.pcpower.com/products/power_supplies/selector/dell.htm

The only price-break I could find is here:
http://www.pcpowercooling.com/specials/


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