Are the Radeon 6850/70 cards backwards compatable with PCIexpress x16 version 1 motherboards? According to AMDs website is only says it requires on PCIe x16 socket but does not say what version. Also what performace hit will I get by only using PCIe 1.0 . I dont have enough to invest in a completely new system as I am running an athlon 64 x2 6000+, now with 3gb ram, 1tb HD, radeon 3870 512mb, 650watt Coolermaster PS. This is a modified Gateway unit. Later I will put together a new unit but in this economy money is tight and the new CPUs and MBs are to be released soon so some prioces should drop.