Dell OptiPlex 7040 shuts down under load only when GPU is installed

Hello everyone,

I have a Dell Optiplex 7040 MT with the following specs:

• Intel i5-6500

• 12GB DDR4 RAM (one 4GB stick and one 8GB stick)

• Added MSI GeForce GT 730 2GB DDR3 GPU

About eight months ago, my system started shutting down under stress and sometimes failing to restart. After removing the GPU, it worked again, but performance dropped significantly in graphics-heavy tasks, which was expected. I suspected the power supply was the issue, as it hadn’t been replaced in over seven years and likely couldn’t provide enough wattage under load.

I replaced the power supply with the same model as the original, but now the system exhibits the following behavior even without the GPU installed: the fans spin for a few seconds, then stop, and this cycle repeats endlessly. There is no POST, no display, nothing.

If I reinstall the GPU, the same behavior occurs.

I’m looking for advice on what could be causing this and how to fix it.

Re: MSI GeForce GT 730 2GB DDR3 GPU

if this is the MSI gpu w white fan it is reviewed as a quite old gpu masqueraded as a good product.  I think the fan is designed not to spin when idle sometimes fooling user as a "bad" card.

try a different Dell oem gpu for 7040 MT which is better than MSI 730.

Supports optional discrete graphics MT/SFF: nVIDIA GeForce GTX 745 (MT only), AMD Radeon™ R7 350X, AMD Radeon™ R5 340X

sofar the story is suggesting the system crashes when gpu is asking for reasonable power up to 75 W spec of 730.  the GPU worked in another system (?PSU?motherboard).  Dell psu supplies 12V power to oem mobo which allocates power to PCIex16 slot to power gpu.  It can be argued that the mobo fails in this power allocation.  Using another low power gpu can prove that gpu itself has not the slightest guilt in this issue. 

PS I would also try Windows 7 OS just to test

7040: Microsoft® Windows 10 Home 64 - bit, Microsoft® Windows 10 Pro 64 - bit
Microsoft® Windows 8.1 Standard 64-bit, Microsoft ® Windows 8.1 Pro 64-bit
Microsoft® Windows 7® Professional SP1 (32/64 bit)

The Optiplex 7040 was introduced in 2015.  May need to test or replace size 2032 CMOS battery.  Bad batteries affect BIOS and therefore PC operation.  Bizarre problems depend on the model.

The 240w PSU is plenty for the GPU cards you're trying.  The GT 730 is only 49w.

The 53w RX 6400 is also a  good card to try.

@bradthetechnut​ Thank you for your reply,

I did replace the CMOS battery, of course.

@redxps630 Hello, yes, it is the MSI GPU with the white fan design. I’m certain the card isn’t faulty—I tested it thoroughly in another PC (a Dell OptiPlex 3010) on both Windows 7 and Windows 10, and it never crashed. I also tried using the bottom PCIe slot in my Dell OptiPlex 7040, but the same issue occurred: it crashes under even the slightest load.

Is there any other way I can test this without having to buy another GPU? I’d much rather put that money toward a replacement motherboard, since that would be cheaper than purchasing another GPU just for testing.

I suggested "clear cmos by mobo jumper".  have you tried that step?

a mobo with corrupted bios can conceivably fail to allocate power to dGPU appropriately under load.  replace cmos battery only does not clear cmos.  If cmos clear makes no difference, sell the 7040 as is and get a newer Optiplex.  understand you already invested on a new psu replacement.  this may become a sink hole where you can keep on throwing in cash to fix this or that, which imo is not worth it given its age.

at bottom of mobo there is instruction on the jumpers.

another thing you can try is to move the service jumper to enter service mode which disables Intel ME.

"I suggested "clear cmos by mobo jumper". have you tried that step?"

There's also instructions for that in a link:  BIOS Reset

@bradthetechnut​ Yes, I did clear the CMOS using the motherboard jumper (not just by replacing the battery), but the same problem still occurred

@redxps630​

Yes, I did clear the CMOS using the motherboard jumper (not just by replacing the battery). I also tested with the service jumper in service mode, but the same issue occurs.

From my perspective, the motherboard seems like the only component left that could be causing this problem. That’s why I think it makes more sense to replace it rather than sell the whole system and buy another OptiPlex. A replacement board on AliExpress is around $80, which is still much cheaper than starting over with a new machine.

So to conclude, the motherboard is the fault, right? 

@anne_droid @redxps630 @bradthetechnut I should also mention that the GPU used to work fine in my Dell OptiPlex 7040 MT. The crashing under load only started happening one day out of the blue, so I don’t think this is a compatibility issue.