You could try it. Clean the CPU and the heatsink (CPU-contact area) with a coffee filter using a little rubbing alcohol until they are shiny with no gunk. Properly apply a good thermal interface material (e.g. Arctic Silver 5). Mount the heatsink firmly against the CPU. Attach the fan and connect the fan power lead to the motherboard. Enter the BIOS @POST to set your thermal alarm or shut-down temperature. Save and exit. Boot into your OS, and monitor the CPU temps with Core_Temp99 (It loads to the tray where you can see the CPU core temps).
I guess the only way to know for sure is to try. I haven't seen another solid copper HSF to compare it to, even to know how big a fan I'd need, and right now, I'm not willing to gamble with my X4, but maybe in the future.