If you mean the comment I did about the Connector Feets of his Graphic card, I mean exactly those (the Connector Feets of that Graphic Card) and NOT to remove the Ram Chips from that Card (which you'll need to use very hot Air!)!
PCIe 2.0 motherboard slots are completely backward compatible with PCIe v1.x cards. But not the other way around. If your motherboard is 1.1 spec, you need a 1.1 addon card, not a 2.0
System Requirements: PC compatible with Intel Pentium 4/Xeon or AMD Opteron class processor or higher Open PCI Express x16 lane slot SLI requires an open x16 electrical and mechanical slot and a second x16 mechanical slot with x16, x8 or x4 electrical capability SLI Frame Rendering requires optional SLI connector, PNYPN 91004732, order separately
I know x16 1.1 is same speed as 2.0 x8 (~). So if there is a board with 2 different forms of pcie, perhaps OP needs to check what slot its in.
The Nvidia QuadroFX 3450 is an older Card and the direct successor of the 3400 (AGP). According to the infos on the Internet, the only relevant limit is the x16 PCI-E Bus, which isn't limited to PCI-E 1.1 or 2! That card was used on HP Machines and it's possible, if you're one is an origin of an HP and your computer not, that it may get problems running because HP has 'modified' the firmware of their cards. I would first try to use the original Driver and set those driver to Compatibility Mode of the OS it were assigned for upfront of installation. If you still face problems after all testings of different driver, contact the Manufacturer of that card, submit all your negative findings and ask for help.