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.


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.

I had to order two from ebay, because the first one was just crimped and one of the wires was loose.  Here is what it looks like on Amazon:  Click here to see what it looks like on Amazon.

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

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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


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.


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

Silent Market

IS there a motherboard that fit in this case?

I have the i5 7040 and I run a 1050ti in it overclocked its a solid rig when you keep within the 240watt power target my 1050 clocks up to 1928 core clock and 3600 on the ram speed its a good computer maybe something happened to the pci slot on your motherboard the card you picked would never work on slot power because it needs 2 6 pins to power up so a PSU would be needed to get it up and running I was planning to put a zotac 1080ti mini in mine but its not worth the… Read more »

I got 7040 i7 with 16 Gb ram from office, before serious digging I brought a PNY Quadro 4000 PCI 2Gb Nvidia graphics card on eBay, still in transit not yet reached.there is a 6 pin power connector on the card, I found some SATA power adapters to 6pin atx,the PSU in 7040 rated at 240W and the max on Quadro is 140W what you think will it work ? or will it fry my PSU as well will SATA power adapter is enough for it