15 specifications

AMD Ryzen 5 8645HS vs AMD Ryzen 7 4800H

On paper, the AMD Ryzen 7 4800H has more cores (8 against 6), the AMD Ryzen 5 8645HS boosts higher, and the AMD Ryzen 5 8645HS carries more L3 cache. Specifications describe what each chip is designed to do; how much of that either one holds under continuous load is a separate question.

11 specifications · 5 with a higher side

Full specifications

AMD Ryzen 5 8645HS

AMD · Ryzen 8040 (Hawk Point, Zen 4) · Laptop

Full specifications

AMD Ryzen 7 4800H

AMD · Ryzen 4000 (Renoir, Zen 2) · Laptop

Cores and clocks

Cores

Threads

Base clock

4.3 GHz

2.9 GHz

Boost clock

5.0 GHz

4.2 GHz

Cache and power

L3 cache

16 MB

8 MB

TDP

45 W

35 to 54 W

Total cache (L2 + L3)

22 MB

Not verified

Platform

Socket

FP7, FP7r2, FP8

FP6

Process

4 nm

7 nm

Integrated graphics

AMD Radeon 760M

AMD Radeon Graphics (7 CU)

Launched

Not verified

2020-03-16

A check marks the higher figure only on rows where higher is unambiguously better. Rows without one are not ties; they are specifications where “better” has no meaning.

Reading the table

What the difference means.

Cores and threads

The Ryzen 7 4800H has 8 cores and 16 threads against 6 and 12. More threads help with work that can be split into many pieces at once: rendering, compiling, video export, running several heavy programs together. They do little for work that runs on a few threads, which includes most games and most everyday software, where the speed of one core decides the result.

Boost clock

The Ryzen 5 8645HS boosts to 5 GHz against 4.2 GHz, 19 percent higher. Across generations it is not a guide to speed on its own, for the reason above. Boost is also a peak: it is held for seconds to minutes, on one or two cores, while the cooling and the power limit allow. What either chip settles at under a long load is lower, and it depends on the cooler and the motherboard as much as the chip.

Cache

The Ryzen 5 8645HS carries 16 MB of L3 cache against 8 MB. Cache is fast memory on the chip, and a larger one means the cores wait on main memory less often. Games, large spreadsheets and compiling respond to it; rendering and video export, which stream through data in order, respond much less.

Power and cooling

The Ryzen 7 4800H is rated at 54 W against 45 W. The rating is the heat the cooler has to move for the chip to hold its speed, and modern chips draw well above it in short bursts. In a laptop the maker chooses the real limit inside a range, so the same chip can behave like two different processors in two machines. That spread is what a sustained test measures and a specification sheet cannot. A chip whose cooling falls short does not fail. It slows down, and it does so after the first minute, which is why short benchmarks miss it.

Platform

Laptop processors are soldered to the board, so this is a choice between machines, not between chips you can swap. What differs between two laptops with these parts is mostly the power limit and the cooling the maker gave each one.

Manufacturing process

The Ryzen 5 8645HS is built on a 4 nm process against 7 nm. A finer process generally does the same work for less power. The names are marketing labels rather than measurements, though, and they are not comparable between manufacturers, so treat the row as a sign of how recent the design is and no more.

Which to pick, on paper

Rendering, compiling, video export: Ryzen 7 4800H; 16 threads against 12. Work that uses every thread scales with how many there are.
A quiet or compact build: Ryzen 5 8645HS; 45 W against 54 W: less heat to move, so a smaller cooler and slower fans.

What no table says

How much of its speed a processor keeps after the first minute depends on the cooling and the power limit of the machine it is in. If you own one of these, measure it: the test is free and runs in this browser.

Free CPU stress test

Questions

Is the Ryzen 5 8645HS better than the Ryzen 7 4800H?: By need, on the specifications: rendering, compiling, video export: the Ryzen 7 4800H; a quiet or compact build: the Ryzen 5 8645HS. No specification says how much speed either one keeps under a long load; that depends on the cooling and the power limit of the machine it is in, and it is what a sustained test measures.
Do the Ryzen 5 8645HS and the Ryzen 7 4800H use the same socket?: Laptop processors are soldered in place, so neither can be swapped for the other.
Does the Ryzen 5 8645HS or the Ryzen 7 4800H have integrated graphics?: Both do: AMD Radeon 760M on the Ryzen 5 8645HS and AMD Radeon Graphics (7 CU) on the Ryzen 7 4800H.
Which runs hotter, the Ryzen 5 8645HS or the Ryzen 7 4800H?: The Ryzen 7 4800H is rated at 54 W against 45 W, so it produces more heat under load and needs the larger cooler. How hot either one actually runs depends on the cooler and the case more than on the chip.

More comparisons

Every figure on this table is a design target. None of it is a measurement.

Nothing above describes how a processor behaves twenty minutes into a sustained workload, which is where two chips with nearly identical specifications routinely diverge. A boost clock is a ceiling the vendor permits, not a rate the chip sustains, and whether it holds depends on the cooling, the case, the power profile and the room. None of those appear on a specification sheet.

We deliberately do not reduce these figures to a single score. A composite invented from specifications would look authoritative and measure nothing, and choosing the weights would be choosing the winner.

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