Hi sinsin. Not clear on the request and relationship to the PCIe adapter. This PCIe adapter and others (any) are designed to operate to the PCIe specification. This means that you do not have to alter any other clock source to make it function correctly. You should not have to nor is it recommended to change the clock to make the adapter operate. From a hardware point of view, the PCIe adapter should be fine but perhaps there is lacking support in the software for this adapter ? Please supply more details and why you are concluding that the clock needs to be changed.