Dell Optiplex 7040 psu and gpu upgrade.

I wanted to upgrade my dell optiplex 7040. I got it at a government surplus auction and was surprised when it had an i7-6700 and 32gig of ddr4 memory. That’s better than the one I have. I thought it would be easy, just get a new power supply and graphics card. Here is a picture with the graphics card in it.

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I was amazed that the geforce 660 ti even fit inside of it.  It was tight but it fit and closed just fine.   The power supply would not fit inside and I am not against a ghetto computer so I was going to leave it outside and use gorilla tape to attach it.  I tested it of course before doing anything permanent and nothing showed up on the lcd screen.  No signal whatsoever.  After doing a bit of research I found out that these dell motherboards limit the pci-e slot wattage to 35 watts.  It is supposed to be 75 watts, so the card wasn’t even turning on.  Frustrating to say the least.  The power supply was a challenge too because these optiplexes use a propriety 8 pin supply connector. I  tried to solder one up based on some pictures I saw, but was missing the key component.  The 5v always on line is actually 12v in dell optiplex 3020, 7020, and the 9020 series.  I got on ebay and ordered one.  It worked great, but like I said, the motherboard just doesn’t give the pci-e slot enough juice for these high end graphics cards.  Optiplexes are great for energy efficiency, the psu that comes with it is only 240 watts.

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6 Comments on "Dell Optiplex 7040 psu and gpu upgrade."

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Johnny
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could you share a picture of how you have connected the graphics card and the motherboard with the new power supply

TheDude
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I am curious how much you paid for the 7040 at auction. We use this computer at work for programming and I too was surprised when I looked at it’s specs. However, the one I use only has 16GB of RAM. This was an interesting read. Thank you for sharing.

Sam
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Hey man, so in the end, you were able to use the new graphics card just as long ass you upgraded your PSU? or did you have to buy a new motherboard