I have a carda card with a half-length PCI Express x8 Gen 3 output. Is it compatible with Dell Precision 3660 Tower which has one PCIe x4 Gen3, one PCIe x4 Gen4, and one PCIe x16 gen5 (for the GPU only)? Essentially I want to see how is a half-length x8 different from an x4 PCIe slot?