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Geforce7900, power supply & Dell Optiplex

  • Graphics Cards
  • Power Supplies
  • Optiplex
  • Graphics
Last response: in Graphics Cards
November 7, 2011 1:22:36 AM


I don't know much, so here are the facts, and after my questions if anyone can help.

I recently got an old optiplex 745 for a $100 from my university. it came with an ATI radeon 9200 64mb. no manual, so i am not sure what mobo it has.

I wanted to install a geforce 7900 256mb that I got for free, since it seems a little better. It recognized it and it's running but I had a window saying I should plug the power cable. there is a 6 pin flat

the video card box says the requirement are 400w and the card need a direct cable. the optiplex has a 305w power supply.

According to what I read if there is no cable, the card performs accordingly to the 15 or 20w that it gets from the PCI-e, and if I had it connected it would get 75w. and I see the 6 pin connector.

I don't know much, so after the obvious I am lost!

1) I don't know what kind of cable I need! does it go to the motherboard or the power supply. there is a couple unused cables/plugs coming from the power supply, one 5 pin (for another hdd) and one 4-pin (like for diskette drive). Is there some kind of adapter from one of those?

2) is 305w enough? It only has one optical drive and one 7200 hdd. so I guess its not using all the power.

3) do I have to get a 400w power supply. how do I know if the mobo supports it? CPU was $75 so I dont want to spend $50 in a power supply. If I do have to get one, any recommendation?

or should I just go back to the original radeon 9200 64mb?


More about : geforce7900 power supply dell optiplex

a b U Graphics card
November 7, 2011 1:32:50 AM

Your computer is so old, you shouldn't bother with it... Just get a $500 gaming build and it can do mostly everything you want but for the minimum...
a c 105 U Graphics card
a b ) Power supply
November 7, 2011 9:23:10 AM

You can use a molex adapter.
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Best solution

a c 105 U Graphics card
a b ) Power supply
November 7, 2011 9:54:25 AM

O, and the psu could be enough, Dell psu are quite good, but it will be close. Pitty you didn't get a hd6670, this would run without extra cable and doesnt use that much power.
November 16, 2011 11:33:10 PM

thanks, I bought the molex cable but I couldn't see where to connect on the PSU. It has the 6 pin for video card on one side and a male 4 pin in the other, so I wonder if I have to get a male-male coupler to connect the molex to one the unused HDD 4-pins cables coming from the PSU.

eehhmmmm…. I know the computer is old, that is why it cost $75, and with what it has (maybe a couple more gigs of RAM) it can run the same programs I was running on WinXP 4 years ago (3d modeling, graphics, video, augmented reality) I have been working with this for 10 years, and you would be surprised for most things you don't need a $2000 computer, so I am not getting a 500 game build...
I also have an imac with dual boot (win & macOS), but it's easier to have to computers running with both OS than having to reboot and do everything in one.
November 16, 2011 11:34:13 PM

Best answer selected by gouvrit.