This type of compatibility depends on the computer manufacturer, in your case Dell.
Based on the picture below you will see that the processor is supported on three type of chipset but not all of them support 3rd generation processors.
QM67 supports 3rd generation processor
HM67 no support for 3rd generation processor
HM65 supports 3rd generation processor
Please check your chipset type and double check processor compatibility with Support | Dell US