Amazon.com: BINGKERS 240W H240AS-00 Power Supply Fit for Dell OptiPlex 390 790 960 990 3010 7010 9010 Small Form Factor SFF System Desktop Computer 3WN11, L240AS-01 : Electronics
TOP for Dell Studio Slim Desktop 540s 537s 560s PSU 250W SFF DT Power Supply USA | eBay
Which Dell Optiplex MT (any model 990, etc.) can I change the graphics card without upgrading the PSU? Which GPUs would work? - Quora
Amazon.com: 250W L250NS-00 H250AD-00 F250AD-00 Power Supply Unit PSU for DELL Optiplex 390 790 990 3010 DT Inspiron 530s 537s 540s 545s 546s 560s 570s 580s Vostro 200s 220s 230s 400s Studio