GPU on PCI-E 1.0

You should check with the motherboard manufacturesr website for any known compatability issues. There will be a list of suported CPU's and GPU's on the web site.
But basically it should be fine, there is no definate issue with compatability and most work.

Mactronix

Yes it should work without any problems. PCIE 2.0 cards are backward compatible with PCIE 1.0 slot.

Even i'm running a PCIE2.0 card on a 1.0 slot.

There will be no problems at all!!
And it won't even bottleneck the card  

Enjoy!!

Should be fine, unless you have an early PCI-E board that wasn't 100% compliant. This was seen on early PCI-E 1.0a boards. Even then, the are usually BIOS udpates to address the issue so you may want to check your Motherboard makers website.