How to Upgrade Your CPU | Hardware Secrets

Socket 775 is the socket type currently used by Intel CPUs. If you have a socket 775 motherboard this means you have a Socket 775 Celeron D, a Socket 775 Pentium 4, a Socket 775 Pentium 4 Extreme Edition, a Pentium D, a Pentium Extreme Edition, a Core 2 Duo, a Core 2 Extreme or a Core 2 Quad. Keep in mind that some of these CPUs are available for other sockets as well, so we are talking specifically about socket 775 models here. In order to know what is the fastest CPU you can install on your motherboard, you will need to know what is the maximum FSB clock rate your motherboard supports. Typical values are 533 MHz, 800 MHz and 1,066 MHz.

To make things simpler, we compiled two tables, shown below. At one side you have your motherboard FSB and on the other which CPUs are supported.

FSB	Celeron D	Pentium 4	Pentium 4 Extreme Edition	Pentium D	Pentium Extreme Edition
533 MHz	All socket 775 models, available up to 3.2 GHz (“351” model).	All socket 775 models up to 2.66 GHz, and 2.80 GHz, 2.93 GHz and 3.06 GHz models. Be careful, as there is a 2.80 GHz version also available with an 800 MHz FSB.	Not supported.	So far only 2.66 GHz model (“805” model). *	Not supported.
800 MHz	All socket 775 models, available up to 3.2 GHz (“351” model).	All socket 775 models up to 2.80 GHz, except the 3.73 GHz model.	All socket 775 models up to 3.40 GHz.	All models, available up to 3.60 GHz (“960” model). *	So far only 3.20 GHz model (“840” model). *
1,066 MHz	All socket 775 models, available up to 3.2 GHz (“351” model).	All socket 775 models, available up to 2.80 GHz.	All socket 775 models, available up to 3.73 GHz.	All models, available up to 3.60 GHz (“960” model). *	All models, available up to 3.73 GHz (“965” model). *

* Older socket 775 motherboards do not support Pentium D, Pentium Extreme Edition, Core 2 Duo, Core 2 Extreme and Core 2 Quad CPUs. This happens because of the new power specs required by these CPUs

FSB	Core 2 Duo	Core 2 Extreme	Core 2 Quad
533 MHz	Not supported.	Not supported.	Not supported.
800 MHz	So far only 1.80 GHz model (“E4300” model).	Not supported.	Not supported.
1,066 MHz	All models, available up to 2.66 GHz (“E6700” model).	So far only two models are available, X6800, a dual-core running at 2.93 GHz and QX6700, a quad-core running at 2.66 GHz.	So far only 2.40 GHz model (“Q6600” model).