Need to purchase GPU for Inspiring 620 i3-2120

The 620 is too small and its not a DELL Precision T3500 or Mac Pro.

Worse is the 620S which has very few options.

None of the GPUS below physically fit into the 620 any model.

If you change power supply to EVGA 750 B1 you could add a short MINI ITX GTX 950 GTX 960.  This however is ONLY on the non SLIM version aka MINI TOWER 620 NOT the 620S  aka Slim.

http://barefeats.com/rogue04.html

GRAPH LEGEND
GTX 580+ = NVIDIA "Classified" (overclocked) GTX 580 GPU (3 power feeds, 3G VRAM) **
GTX 580e = NVIDIA eVGA GeForce GTX 580 GPU (2 power feeds, 3G VRAM) **
GTX 570 = NVIDIA GeForce GTX 570 GPU (2 power feeds, 2.5G VRAM) **
GTX 680 = NVIDIA eVGA GeForce GTX 680 GPU (2 power feeds, 2G VRAM)
Q6000 = NVIDIA Quadro 6000 GPU (1 eight pin or 2 six pin power feeds, 4G VRAM) **
R5870 = AMD Radeon HD 5870 (2 power feeds, 1G VRAM)
Q4000 = NVIDIA Quadro 4000 GPU (1 power feed, 2G VRAM)
R6870 = AMD Radeon HD 6870 (2 power feeds, 1G VRAM)
GT650M = NVIDIA GeForce GT 650M GPU (built-in Retina MacBook Pro), 1G VRAM
R5770 = AMD Radeon HD 5770 (1 power feed, 1G VRAM)
GTX285 = NVIDIA GeForce GTX 285 GPU (2 power feeds, 1G VRAM)

Ten PCIe GPUs are installed in a 'mid 2010' Mac Pro 3.33GHz Hex-Core. The GeForce GT 650M is built into the 'mid 2012' Retina MacBook Pro 2.7GHz Quad-Core i7. Both Macs were running OS X Mountain Lion 10.8.1. (Follow-up testing with 10.8.2 showed no signficant change.)

Thanks for the response. As far as i understood my PC is compatible for high end use, beside that is what I was looking for. I want to learn few software, so just for a basic use I needed a advise. So advise me what GPU I can go for. There has to be a GPU I can go for. Please dont advise me what I cant go for.

Thanks

Dell Precision Workstations are compatible with high end use.  Inspiron 620 systems are not.  The 620 is not a workstation.

Mac Pro systems and Dell Precision T3500 or better are.

The 620S has little to no Davinci Resolve NVIDIA GPU options.

You did not say which model you have.

The MINI TOWER 620  is on the Left the 620S is on the right.

DaVinci Resolve offloads intensive image processing to the NVIDIA GPU. It also employs YRGB 32-bit floating point.  This means 2GIG GPU ram minimum.

512 Meg and smaller gpu's will not work at all.