Danrf444,
On Passmark Performance test, with 214 results for "Dell Optiplex 960", the highest 7 scores in 3D are:
E8400 > GeForce GTX 750 > 3D = 2982
Q6600 > Radeon HD 7750 > 2190
Q9400 > GeForce GTX 550ti > 2038
Q9650 > GeForce GTX 650 > 1897
E8400 > GeForce GTX 650 > 1894
Q9400 > Radeon HD 7750 > 1893
Q9650 > GeForce GTX 650 > 1862
I like Passmark for this kind of real-world performance information, and besides performance, showing which cards will fit in the case, don't require too much power, and so on The nice feature of the newer GPU's is that generally they are compact and use less power anyway.
And, two or three changes (about $130) in these older systems make a very noticeable difference:
Dell Dimension E520 (2006) Original: Pentium D 830 @ 3.0GHz, GeForce 7300LE (128MB), 2GB DDR2 667 , 2 x WD 320GB > 2X Dell 19" LCD > Windows XP Pro 32-bit
[ Passmark system rating = 384, CPU = 613 / 2D= 248 / 3D=72 / Mem=562 / Disk = 522 ]
Dell Dimension E520 (2006) Revised: Core2 Duo E6700 dual core @2.66GHz > 4GB DDR2 667 > GeForce GT440 (1GB GDDR5) > 2X Dell 19" LCD > Windows 7 Professional 64-bit
[Passmark system rating = 1219, CPU = 2024 / 2D= 457 / 3D=978 / Mem= 828 / Disk=576]
Cheers,
BambiBoom
HP z420 (2014) > Xeon E5-1620 quad core @ 3.6 / 3.8GHz > 24GB DDR3 ECC 1600 RAM > Quadro K2200 (4GB)> Samsung 840 SSD 250GB /Western Digital Black WD1003FZEX 1TB> M-Audio 192 sound card > AE3000 USB WiFi > 2X Dell Ultrasharp U2715H 2560 X 1440 > Windows 7 Ultimate 64 >
[ Passmark Rating = 4032 > CPU= 9247 / 2D= 821 / 3D=3263 / Mem= 2584 / Disk= 2470]