Intel Core 2 Duo E8400 3GHz LGA775 Processor: specs and who it suits

The Intel Core 2 Duo E8400 is a dual-core desktop processor running at 3GHz, made for the LGA775 socket. It's a boxed processor (model BX80570E8400) from Intel's 45nm generation. It is an older part, so it mainly matters to people repairing, restoring or maintaining a PC of that era. Here is what the specs mean.

What the numbers say

The listing gives 3GHz clock speed, 6MB of cache, the LGA775 socket and a front-side bus (FSB) design. Clock speed is how fast each core runs. Cache is a small, very fast memory on the processor that holds frequently used data close to the cores. LGA775 is the physical socket: a land grid array with 775 contacts, so the processor only fits motherboards with that socket.

Two cores

Intel describes the Core 2 Duo as having two complete computing "brains" on one processor. Two cores let the computer run two tasks truly at once, so a system doing several things together, such as browsing, email and playing media, slows down less than an older single-core processor would. Modern software is often built for more cores, so this is a modest design by today's standards.

45nm architecture

The 45nm figure is the manufacturing process. Intel says this generation uses hafnium-based technology, which allowed smaller transistors, more features in less space and better efficiency than previous generations. Intel lists features such as Wide Dynamic Execution, Intelligent Power Capability, Smart Memory Access, Advanced Smart Cache, Advanced Digital Media Boost and HD Boost. In general terms they handle more instructions per cycle, switch off unused parts of the chip, make better use of memory bandwidth, share cache between the cores, and speed up media and image tasks.

What it was designed for

Intel positions the Core 2 Duo for mainstream users: web browsing, email, image editing, downloads and video, often at the same time. That makes it a fit for basic tasks on a legacy computer rather than demanding current software.

The FSB design

An FSB processor talks to memory and the rest of the system through a chipset on the motherboard. This differs from newer processors that build the memory controller into the chip, and it's one reason the motherboard and memory choices for this socket are specific.

Who it suits

It suits owners of older LGA775 PCs who want to replace a failed processor, upgrade from a slower chip on the same board, or build a retro system.

What to check before you buy

• Motherboard support: confirm that your board's chipset and BIOS support the E8400. Some LGA775 boards need a BIOS update, and some don't support 45nm chips at all.
• Socket: the board must be LGA775.
• Cooling: the box version normally includes a cooler, but check the contents and fit.
• Memory: older boards use older memory types, so check what yours takes.
• Operating system: check that your intended software and drivers still support this hardware.
• Condition: make sure the listing describes a boxed, working processor.

The short version

• A dual-core, 3GHz, 6MB-cache boxed Intel processor.
• Built on a 45nm process for the LGA775 socket, with an FSB design.
• Intended for everyday tasks such as browsing, email and media.
• Check motherboard and BIOS compatibility before buying.

Bloiq is reader-supported. Some links may earn us a commission; it never affects what we write. How we make money.