Yes, absolutely. The PCI Express folks did a good job with this.
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PCIe 2.0 is backward and forward compatible with PCIe v1.x. PCI Express 2.0 has good backwards compatibility, new PCIe 2.0 graphics cards are compatible with PCIe 1.1 motherboards, meaning that they will run on them using the available bandwidth of PCI Express 1.1. Overall, graphic cards or motherboards designed for v2.0 will be able to work with the other being v1.1 or v1.0.
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PCIe 2.0 is backward and forward compatible with PCIe v1.x. PCI Express 2.0 has good backwards compatibility, new PCIe 2.0 graphics cards are compatible with PCIe 1.1 motherboards, meaning that they will run on them using the available bandwidth of PCI Express 1.1. Overall, graphic cards or motherboards designed for v2.0 will be able to work with the other being v1.1 or v1.0.
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