Laptop CPU vs desktop CPU

Two processors can list the same core count, the same thread count, and boost clocks within a tenth of a gigahertz of each other, and still be built for different work. One is a mobile part soldered into a laptop; the other seats in a socket on a desktop board. What separates them is not a number printed large on the box.

The power envelope is the real difference

Every processor here records a base power figure — AMD's TDP, Intel's processor base power, a mobile chip's nominal rating. On the desktop side that number starts at 65 watts and climbs from there. On the mobile side it starts at 17 and stops at 55. The two bands do not touch: no laptop chip in this catalog is rated as high as the lowest-rated desktop chip in it.

That gap is the design constraint the rest follows from. A laptop has a battery, a fixed volume of air to move heat into, and a lap it may end up on. Whatever silicon goes into it has to fit that budget, and the way a maker fits a wide chip into a narrow budget is to run it at lower clocks and pull power back sooner. Same cores, less power, less finished work per hour.

Base power is not the whole story either. Every mobile chip in the catalog also records a maximum power figure — Intel's maximum turbo power, AMD's package power tracking limit — and on mobile parts the two numbers sit much further apart than the base rating suggests.

The two 28-watt parts are the row worth stopping on. Both carry the same base rating and they are permitted wildly different peaks, so a base figure on its own does not tell you what a chip is allowed to draw when it is working hard. Read both numbers, and read them as the range a laptop maker gets to choose inside rather than as a promise about any particular laptop.

Base clock, boost clock, and the number nobody publishes

Every mobile chip in the catalog records both a base clock and a boost clock, and the boost figure is always the higher of the two. Base is the speed the part is specified to hold at its base power rating; boost is the ceiling it may climb to when power, temperature and the number of busy cores all allow it.

Neither of those is the speed a laptop settles at during a long export or a long compile. That figure — what the chip sustains once the heatsink is saturated and the fans are at their limit — belongs to the machine, not to the processor, and it varies between two laptops holding the same chip. There is no sustained-clock field in the CPU specification here, because there is no manufacturer figure to put in one. Anyone quoting a sustained clock for a laptop is quoting a measurement of that laptop, and that takes a review of the machine rather than a spec sheet for the chip.

Integrated graphics stops being a fallback

On a desktop chip, integrated graphics is usually a way to get a picture before a graphics card arrives. On a mobile part it is frequently the only graphics in the machine, and the makers treat it that way: every laptop chip in this catalog names the specific graphics silicon it carries, not merely that it has some. That naming matters more here than it does on the desktop side, because the named part is what is going to render everything the laptop shows.

How to choose a desktop CPU covers how the desktop half of the catalog treats integrated graphics, which is a different story — there, some current chips switch it off altogether.

Soldered, and what that means for the price

A mobile processor is soldered to the mainboard of the laptop it ships in. It is not a component someone buys, and it has no retail listing of its own anywhere to be found. That single fact decides what these pages can be.

There is no price history on a laptop processor page, and there never will be — not because the record has not been collected yet, but because no such record exists to collect. What the mobile side of the catalog offers instead is specifications from the datasheet, comparable across chips, so a machine's chip can be read against the chip in the machine next to it. Where a desktop chip's page answers "is this a good time to buy," a mobile chip's page answers "what did I actually get."

What is recorded for a mobile part

For a laptop chip the catalog holds cores and threads, base and boost clocks, cache, base and maximum power, the graphics silicon by name, the process it is built on, and the memory it supports. Several of those are fields the specification treats as optional, because a desktop chip's datasheet does not always state them — but for the mobile parts here, every one of them was published, so every one of them is filled in. A figure a source never stated is left off the page rather than guessed at or borrowed from a sibling chip.

What is not there is anything measured by us. No frame rates, no render times, no battery-life figure. Those depend on the whole laptop, and the chip is one part of it.

How many CPU cores you actually need works through the core-count question itself, and it reads the same on both sides of this divide — a core count sizes a chip to a kind of work rather than ranking two chips. Bring the power envelope to that reading, though. Eight mobile cores at 17 watts and eight desktop cores at 65 are the same count and a different machine.

Every laptop processor in our catalog has its own page, with specifications read from the maker's datasheet. Every desktop CPU has one too, on the same terms, plus the price history a part that is sold on its own can have.