Introduction

AMD's Ryzen 9 7900 "Zen 4" desktop processor is a very interesting product from the company, for people who know what they want and want to save a little on the side. This 12-core/24-thread processor is part of an early-2023 refresh of the Ryzen 7000 series with a trio of 65 W "non-X" SKUs spanning the 7900, 7700 (our review), and 7600 (our review). The idea here is to offer certain power-efficient SKUs that square off against Intel's 65 W non-K 13th Gen Core processors that launched around the same time. With its Ryzen 7000-series, AMD made integrated graphics standard-issue, which means businesses that need desktops with CPU power and who don't want discrete graphics, can opt for any 7000-series processor SKU, just like they would with Intel.



The Ryzen 9 7900 is AMD's third 12-core "Zen 4" processor SKU, the others being the 7900X with a much higher 170 W TDP and the same standard "Zen 4" chiplets; and the enthusiast-segment Ryzen 9 7900X3D, which features 3D Vertical Cache on one of its two chiplets, to significantly boost gaming performance. Each of these SKUs has something going for it, for the Ryzen 9 7900 in this review, it's the tight power limits that make it fall into the 65 W category; coupled with a nice 140 W-capable Wraith Prism RGB cooling solution included in the box (something the 7900X and 7900X3D lack). The iGPU and boxed cooler complete the package for the 7900 to be picked up by business customers.

The Ryzen 9 7900, along with the rest of the Ryzen 7000-series desktop lineup, debuts the new "Zen 4" microarchitecture, which promises a roughly 15% IPC increase over the previous-generation Zen 3, on the backs of a redesigned Front End component, support for new instruction sets, and a larger 1 MB dedicated L2 cache per core. The architecture also introduces support for AVX512, VNNI, and certain AI neural-net building/training acceleration components on the core. A big chunk of the generational IPC uplift also comes from the switch to DDR5 memory. These processors only support DDR5, there's no backwards-compatibility with DDR4 (like on Intel Alder Lake and Raptor Lake). As of March 2023, DDR5 memory prices are definitely on a downward trend, and so businesses should find it easy to buy entry-level DDR5 memory kits in bulk.

The Ryzen 9 7900 ticks at a 3.70 GHz base frequency, with a 5.40 GHz maximum boost (compared to 5.60 GHz of the 7900X). The 7900 has much tighter power limits compared to the 7900X, which should affect its boosting headroom in highly parallelized workloads. For lightly threaded workloads like gaming, this should be less of a problem, which is why the processor has rather generous maximum boost frequencies.

When we first reviewed the 65 W Ryzen 7000-series, we only had the 6-core 7600 and 8-core 7700 to play with, which makes the 7900 a kind of oddity in AMD's lineup. To find its ideal use-cases would be an interesting adventure, especially given its price of $430, which puts it roughly on par with the Core i7-13700K, and $20 cheaper than the 8-core Ryzen 7 7800X3D that the company plans to launch later this Spring in April. What's a bit surprising is that Ryzen 9 7900X currently sells for five dollars less than the 7900 non-X in this review, but you're not getting a CPU cooler with that.

Unboxing and Photography

The Ryzen 9 7900 comes in a pretty big cardboard box, with a premium finish. A small cutout on the front shows the actual processor inside the package.


The Ryzen 7000 series processor package is unlike any processor before it, with its flower-shaped IHS design. AMD says it didn't go with a rounded-square IHS because it wanted to keep some of the electrical SMD ancillaries outside the IHS where they're less affected by temperatures. If you flip the chip, you'll see that unlike Intel processors, there's no central "island" where there are no pins and instead some SMDs.


AMD includes the Wraith Prism with the Ryzen 9 7900.


The AM5 socket retention brace only applies pressure along the two side protrusions of the IHS. Intel sockets have it the same way.

Test Setup

• All applications, games, and processors are tested with the drivers and hardware listed below—no performance results were recycled between test systems.
• All games and applications are tested using the same version.
• All games are set to their highest quality setting unless indicated otherwise.

AIDA64 Cache and Memory Performance

In this first test we're looking at the performance offered by the memory subsystem and the processor's L1, L2 and L3 caches. AIDA64 comes with a great benchmark that provides a nice overview over all these performance characteristics.

Super Pi

SuperPi is one of the most popular benchmarks with overclockers and tweakers. It has been used in world-record competitions practically forever. It is a purely single-threaded CPU test that calculates Pi to a large number of digits—32 million for our testing. Released in 1995, it only supports x86 floating-point instructions and thus makes for a good test for single-threaded legacy application performance.

Y-Cruncher

Y-Cruncher is a highly optimized piece of software that can calculate Pi and other constants to a huge number of digits. It is fully multi-threaded, uses a modern code design and is optimized for all major processor architectures. This ability has made it a popular application, used by the enthusiast community to determine and compare how powerful their overclocked systems are.

Chess Simulation

Creating a worthwhile opponent for the game of chess has been one of the most fascinating tasks for computer programmers for decades. In this test we're using the highly popular Stockfish chess engine to calculate optimal moves in a chess scenario.

Rendering — Cinebench

Cinebench is one of the most popular modern CPU benchmarks because it is built around the renderer of Maxon's Cinema 4D software. Both AMD and Intel have been showing this performance test at various public events, making it almost an industry standard. Using Cinebench R23, we test both single-threaded and multi-threaded performance.