So I may have jumped the gun a little on my latest system: the standard config fitted on the Dell website fitted our needs except for dedicated GPU which I planned on adding after the system arrived.

Problem is the mini tower (micro ATX?) has restricted space and only comes with a 260w PSU.

Initially I had my eye on the Gigabyte RX580 8GB card but that's clearly not going to work.

After plenty of research, I can find smaller cards that will physically fit (I think 8" is the max length I can accommodate) but I'm concerned about PSU sizing: most of the GPUs I'm looking at now have PSU ratings of 300W and above. Is this an unbreakable rule or will the 260w PSU be ok for a 300w rated card?

 

Also, the PSU is classed as: 85% (Bronze) - can anyone shed any light on what that means?

For reference: we're going to run a lightweight engineering CAD-CAM package on this machine so while a dedicated GPU is necessary it doesn't have to high-end.

 

System specs:

Core i7-9700

16GB DDR4 RAM (1x16GB DIMM)

512GB SSD