These are the processors supported by your motherboard:
There are no quad core processors supported on your board. There is no bios update that will help you.
I would stop now and revert to your previous processor. It is possible that what you are doing could damage your motherboard.
Also, this is your board: Intel® Desktop Board D946GZIS Specifications It is 10 years old and no longer supported.
This is the processor you are trying to use: Intel® Core™2 Quad Processor Q9450 (12M Cache, 2.66 GHz, 1333 MHz FSB) Specifications It is 8 years old, and no longer supported.
While the board has socket 775, and the processor uses socket 775, the part that is missing is BIOS support of the processor. Any upgrade processor must be socket and BIOS compatible.
In that processor generation, the quad-core processors actually utilized two dual-core processor dies. As a result, their power requirements were significantly higher than that for dual-core processors (which utilized only a single die). If the board does not list support for quad-core processors, it is likely because the board's voltage regulators cannot provide all of the power necessary. Keeping this processor in the system for any length of time could result in the burnout of the voltage regulators (a non-repairable situation).
I realize that you are likely attempting the upgrade the processor in an effort to keep this older system alive and relevant. IMHO, you are throwing good money after bad. This board is well beyond its (typically 7 year) MTBF and component failures could begin to occur at any time (if they haven't already). I think its time for you to consider replacing this system...
Hope this helps,
This message was posted on behalf of Intel Corporation
Thank you very much to Al Hill and N. Scott Pearson for the comments posted previously.
I just wanted to confirm the information above as correct, as it was mentioned the processor that you are trying to use is not compatible with your motherboard, but you can always choose any of the processors that are showing on the compatibility list.
Any questions, please let me know.