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.


    1. I went and searched for one, but couldn’t find it. I never actually assembled it because while the Power Supply was a whopping 700 Watts, the motherboard only sent 35w to the PCI-E slot. Thus rending the whole project mute. I just bought a new motherboard, ripped the processor and memory out and put the whole thing in a bigger case.

  1. 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.

    1. I put in a bid for 55 dollars on a local government state auction. I think they might have messed up because it was sitting with old dell opti plexes. I have no idea how it got there and I recognized what it was when the other bidders apparently did not. There was two i5’s in the lot too, so quite a lucky day for me.

    1. I had to buy a new motherboard. The one that came with my 7040 only supplied 35 watts to the PCI-E slot. The high end graphcis cards need 70 watts.

    1. I am not sure if there is or not. I doubt it, it seems like is specifically a Dell motherboard. I had to use an old ATX case I had lying around after I got a new motherboard.

  2. 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 effort going to leave it for 1080p 75 HZ gaming and build a new rig for 144 with a thermaltake g3 case about the same footprint with standard ATX motherboard.

    1. 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

      1. It’ll be close for sure. Hope it works 🙂 In my experience it won’t fry until you have fully loaded the cpu and graphics card (or a brown out occurs while you’re doing it). It’ll probably work for awhile and then after a few months ‘boom’ while you are working it’ll go. Hopefully not though! Hope it runs for years for you.

    2. Ah that’s good to know. I searched all over the net trying to figure out if a nvidia 1050 would work or not. As you read above, I ended up just getting a new motherboard and power supply.

      1. Dear ; thanks a lot for sharing your experience ; i just buyed a second hand Dell 7040 optiplex MT i7 ; i have questions ; where did you find on the web the info that the PCI-E Slot only supplied 35 watts on this motherboard ; can’t find info. Other info ; i’m planning to buy the Nvidia Graphhic Card with name Geforce 1030. This card spec said that it’s used 30 w ( It’s also saying that recommanded system power should be 300 W. My Optiplex 7040 is a 240 w : do you thing it would works without “Boom” bug later ? Why did’nt you considere the GT 1030 in fact ? Thanks a lot in advance for any info !!

        1. I read the 35 watt limit on a forum that some one posted, so not a very reliable source. If you draw 300W from a 240W source you will get a boom, no doubt. However it is very rare that you are going to draw 300W, so its a gamble. The GT1030 was not fast enough to play the games I wanted.

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