Compatibility

My comp spec:
Proc core 2 duo E6300
Gigabyte GA 965P DS3
RAM 2 GB run on dual channel
PSU Sylverstone with 500 watt
currently VGA HIS X1650 IceQ.

I want to change my VGA with HD 4870, my question: will it work??
cause my mobo's still use PCIE x16 ver 1.0
THANKS A LOT.