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Power supply upgrade and graphics card for Dell optiplex 755 DT?

I9 have a problem, i have found my old dell optiplex 755 desktop. I am planniong on installing a Core2quad Q6700 proccesor which fits my computing needs but i am in trouble with the graphics card. the one that came with my computer is a 280 watt psu. I did find a decent graphics card (Radeon hd 4890) this one also fits me for the games i want to play, the problem is that it requires 2 6 pin power connectors, the real problem is that there is none coming from my psu, or anywhere in my pc. Is there a good psu upgrade because it requires 400 or 500 watt psu. And if my current one works, is there any way on getting a 6 pin connector to poiwer the graphics card up? or is it worth getting a similar performance gpu without 6 pin power?
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More about power supply upgrade graphics card dell optiplex 755
  1. The PSU in this computer is a proprietary shape and finding an aftermarket replacement is not easy. In fact this is the only one I know of, truth be told that I suspect the build quality, only about 250W on the 12V rail.
    https://www.atxpowersupplies.com/350-Watt-Dell-F5114-Power-Supply-F5114-350W.php

    Quite honestly, do not get this GPU, it will not work for a couple of reasons. It is a 190W card, you would likely blow up the the replacement PSU above if you installed this card. Definitely would smoke your 280W PSU.
    https://www.techpowerup.com/gpudb/244/radeon-hd-4890

    Also, pretty sure that the PCI-e x16 slot on this mobo is a restricted wattage slot, will only supply 25W and not the normal 75W. You can see it stenciled right onto the board (see pic in the link). This presents another problem in the you have two 6-pin cables from the PSU, each supplying 75W max. So the total power that can be provided is 175W (75W+75W+25W = 175W). This also presents a problem in finding low power cards that have 6-pin PCIe connectors.
    https://sc01.alicdn.com/kf/HTB1bLZjIXXXXXXsXFXXq6xXFXXXo/221231019/HTB1bLZjIXXXXXXsXFXXq6xXFXXXo.jpg

    This means the following for TDP wattages
    No 6-Pin connector on card: Wattage range up to 25W
    One 6-Pin connector on card: Wattage range up to 100W
    Two 6-Pin connectors on card: Wattage range up 175W (but as stated before I would not be using these because of PSU)

    Next the 755 DT only takes low profile cards, this likely excludes the HD 4890

    To top it all off, the HD 4890 card is really old and isn't very powerful.

    So your problem comes down to finding a low profile card with at least one 6-pin power connector that has the same or better performance as compared to the HD 4890 and which will be compatible with the PSU, motherboard and BIOS. Here's a database that shows the different chipsets that have one 6-pin connector. http://
    You can also set it for two 6-pins.

    I tried to find a solution using the connectors filter in TechPowerUP, the TDP filter in PCPartPicker and the low profile filter at Newegg. No luck. Maybe there is something out there, I don't know.
  2. imsqam said:
    The PSU in this computer is a proprietary shape and finding an aftermarket replacement is not easy. In fact this is the only one I know of, truth be told that I suspect the build quality, only about 250W on the 12V rail.
    https://www.atxpowersupplies.com/350-Watt-Dell-F5114-Power-Supply-F5114-350W.php

    Quite honestly, do not get this GPU, it will not work for a couple of reasons. It is a 190W card, you would likely blow up the the replacement PSU above if you installed this card. Definitely would smoke your 280W PSU.
    https://www.techpowerup.com/gpudb/244/radeon-hd-4890

    Also, pretty sure that the PCI-e x16 slot on this mobo is a restricted wattage slot, will only supply 25W and not the normal 75W. You can see it stenciled right onto the board (see pic in the link). This presents another problem in the you have two 6-pin cables from the PSU, each supplying 75W max. So the total power that can be provided is 175W (75W+75W+25W = 175W). This also presents a problem in finding low power cards that have 6-pin PCIe connectors.
    https://sc01.alicdn.com/kf/HTB1bLZjIXXXXXXsXFXXq6xXFXXXo/221231019/HTB1bLZjIXXXXXXsXFXXq6xXFXXXo.jpg

    This means the following for TDP wattages
    No 6-Pin connector on card: Wattage range up to 25W
    One 6-Pin connector on card: Wattage range up to 100W
    Two 6-Pin connectors on card: Wattage range up 175W (but as stated before I would not be using these because of PSU)

    Next the 755 DT only takes low profile cards, this likely excludes the HD 4890

    To top it all off, the HD 4890 card is really old and isn't very powerful.

    So your problem comes down to finding a low profile card with at least one 6-pin power connector that has the same or better performance as compared to the HD 4890 and which will be compatible with the PSU, motherboard and BIOS. Here's a database that shows the different chipsets that have one 6-pin connector. http://
    You can also set it for two 6-pins.

    I tried to find a solution using the connectors filter in TechPowerUP, the TDP filter in PCPartPicker and the low profile filter at Newegg. No luck. Maybe there is something out there, I don't know.





    I don't have the problem of psu because i found the sapphire radeon hd 7750 low profile and it fits my needs since it doesn't require and doesn't have 6 pin connector, the last question is, does that 350 watt psu able to handle it, or my current 280 watt?
  3. The HD 7750 will not work due to the 25W restriction on the PCI-e slot, the HD 7750 is a 55W card. Please note the wattage ranges I listed above.
    http://gpuboss.com/graphics-card/Radeon-HD-7750
  4. imsqam said:
    The HD 7750 will not work due to the 25W restriction on the PCI-e slot, the HD 7750 is a 55W card. Please note the wattage ranges I listed above.
    http://gpuboss.com/graphics-card/Radeon-HD-7750


    what do I do then
  5. imsqam said:
    The HD 7750 will not work due to the 25W restriction on the PCI-e slot, the HD 7750 is a 55W card. Please note the wattage ranges I listed above.
    http://gpuboss.com/graphics-card/Radeon-HD-7750


    the thing is that the one i was looking at , the sapphire radeon hd 7750 low profile 1gb, that does not have a 6 pin
  6. Best answer
    There is nothing that you can do with this GPU, it will not work.

    But to be on the safe side, please open your case and look to see if there is the "25W" stenciled on your motherboard like in this picture. The picture is upside down, it is just below the black PCI-e x16 slot in the upper left area of the picture.
    https://sc01.alicdn.com/kf/HTB1bLZjIXXXXXXsXFXXq6xXFXXXo/221231019/HTB1bLZjIXXXXXXsXFXXq6xXFXXXo.jpg
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