Upgrading PSU in Dell OptiPlex 3050

[luismfranco]

Hi,
I recently purchased a Dell OptiPlex 3050. To my surprise, its motherboard comes with a 6-pin socket for the power supply. The previous version, OptiPlex 3040, has an 8-pin socket and can be easily powered through a 24-20pin to 8-pin adapter cable connected to practically any PSU. I need to upgrade the PSU so that I can power a GeForce GTX 750Ti I want to install on this motherboard. Is there any adapter cable I could use for a motherboard 6-pin socket? Also, would it be safe to power the GPU independently with a 500W PSU and keep the default Dell 240W PSU for the motherboard and CPU? Any help would be really appreciated.
Here are some images:

 

[william p]

Most 750Ti don't need a power cable and can run off of the PCIe slot 75W. GTX1050, and 105Ti can also also run this way. Just get one that doesn't need the power cable.

 

[luismfranco]

Thank you for your answer william p. That is exactly what I'm trying to do. However, the GTX 750Ti requires a minimum of 400W, which is not compatible with the default Dell 240W PSU. The issue here, is to be able to connect any +400W PSU (mine is a Thermaltake TR2 500W, btw) to OptiPlex 3050's 6-pin MoBo.

 

[william p]

The GPU itself is 65W. The 400W PSU assumes 130W CPU, Mid, or Full tower case with lots of drive bays ans expansion slots. Also aftermarket PSUs are rated peak power, and Dell PSUs are rated continiuos. A Dell 305W PSU when tested scored 400W peak by aftermarket standards. Basically dell PSUs will power all the slots and bays in the computer they're installed in. Your Optiplex has a 95W CPU limit+65W GTX750Ti=160W. That leaves 80W for everything else. If you have enough memory that you're not thrashing your HDD all the time you should be OK. Lots of people have run these in Dell SFF computers.