Yorkfield CPUs supports cmpxchg16b instruction, but many MBs of that era had errors in BIOS, preventing instruction to work, so update BIOS first, if possible.
As Al_Hill and JFFulcrum mentioned above, the processor supports the instructions for Windows* 10, however, the processor is not the only component on your computer which determines whether it Supports windows 10 or not. Depending on your motherboard a BIOS update may be required.
Please confirm your computer's configuration in order to have a better understanding of your system capabilities and possible compatibility with Windows 10*
You may try this update (Microsoft's Tool) to check you system compatibility for Windows 10* before you install it:https://support.microsoft.com/en-us/kb/3035583
You may get more information here Compatibility report for Windows 10: FAQ - Windows Help
*Other names and brands may be claimed as the property of others.