What is the exact model of the board D915 come in different types eg. GAv, GLVG etc etc please specify which mobo and what is the CPU you plan to put in?
Many many dual cores out there...... specify model too
Nope they don't support the processors the only processors they support are http://www.intel.com/support/motherboards/desktop/d915gav/sb/CS-026958.htm
Intel® Pentium® 4 & Intel® Celeron® D