Your slot is NOT GEN1 if it was a PCI-E 2.1 or 3.0 based card would not work at all in ANY slot due to line code being 8b/10b  instead of 128b/130b.   MSI GT1030 or DELL 8CCF1 is fine and works. [URL] I recommend full height card for a tower [URL] [URL]#kf   These issues were discussed as early as 2009 with windows 7.  PHY or line code is not backwards compatible all the way to 1.0.  Never has been never will be.  PCI-E 3.0 4.0 5.0 etc have the same ISSUES because they change it all the time.  This is one of the reasons they stopped supporting legacy and stopped supporting 32 bit os.  From now on its 64 bit only windows 10 only.There is a difference but its insignificant as far as FPS Imho.  Your CPU will never have the bandwidth to push an X16 card at 2.1 speed aka 8Gbps because the total CPU bandwidth is about 10Gbps. [URL]   X16  PCI-E 2.1 is  8 Gbps X08  PCI-E 2.1 is  4 Gbps X16  PCI-E 1.1 is  4 Gbps X08  PCI-E 1.1 is  2 Gbps   Thats also why fitting in the slot is NOT backwards compatible back to 1.0. Dell™ optiplex™ 330 technical guide [URL] X8 Gen 2 is the same speed as X16 Gen1 Broadcom (BCM5787) Gigabit LAN 10/100/1000 (WOL, PXE, and ASF2.0)ADi 1984 high Definition audioIntel® G31 Express Chipset (ICH7R)[URL]     [IMAGE]330 Tower has 305W power supply which is fine [IMAGE]You dont have the bandwidth to support PCI-E 3  
So I have an optiplex 330 off with a Xeon E3120 CPU (similar to core duo e8400).  I have a msi gt 210 low profile card and I want to upgrade to a GT710.  I have found two cards that I think fit in my case. But I don't know which one will work better, based on my PCIe slot. My slot is gen 1 with 16pins. I think both are compatible.  Should I choose the card with the faster memory but half the connector pins or  double the pins but slower memory? Card 1: [URL] Card 2: [URL]#ov  I hope the question was clear.  Thanks, Antonis                                                                                    
Optiplex 330 GPU Compatibility.