Introduction

AMD Zen 4 is here, and the new Ryzen 9 7950X 16-core processor in this review is out to restore the company's top-spot in the PC processor industry. With Zen 4, the company is firmly into the next-generation era, with the latest high-IPC CPU cores supporting new instruction-sets for future applications; and support for the latest I/O standards such as DDR5 and PCI-Express 5.0. The Ryzen 7950X targets both enthusiast-gamers, professional game-streamers, as well as overclockers. This is a classic multi-core processor, and all 16 of its CPU cores are what Intel would consider "performance" cores. With this generation, AMD is making integrated graphics standard, so even businesses and academic/scientific customers who need the compute muscle without graphics cards, can look for Ryzen 7000-series processors. While the iGPU isn't gaming-grade, it's intended to be as capable, if not more, than the one competing Intel processors ship with.



The new Zen 4 architecture introduces a generational 13% IPC uplift, which when combined with the high boost frequencies afforded by the new 5 nm process, work out a single-thread uplift of 29%. The company claims that not only do these processors nullify the gaming performance advantage of Intel processors, but also dominate in productivity tasks, where the 16 P-cores offer up to 44% more multi-threaded performance than the previous-gen 5950X, which already enjoyed a slight performance lead over the i9-12900K "Alder Lake," with creator workloads that scaled across cores. The Zen 4 core comes with double the L2 cache size, now at 1 MB, while the L3 cache of the processor totals to 64 MB.

Boosting the creator credentials of the Ryzen 9 7950X is its platform I/O. AMD's PCI-Express Gen 5 implementation goes a step ahead of Intel's. You get Gen 5 not just for the x16 PEG slot, but two additional x4 connections, besides the chipset-bus. It's possible for motherboard designers to wire out two Gen 5 M.2 NVMe slots attached to the CPU, without eating into the x16 PEG bandwidth. The Ryzen 7000 series exclusively supports DDR5 memory, which means no backwards-compatibility with DDR4. New-generation connectivity is why the company had to develop Socket AM5.

AM5 is a new LGA socket, much like Intel's desktop sockets for the past couple of decades. It wires out DDR5 memory, 28 lanes of PCIe Gen 5, platform I/O that include more 20 Gbps USB 3.2 ports; modern display connectors such as DP 2.0, and most importantly, comes with a smarter, more capable power architecture. The socket enables 2-way communication between the processor and voltage regulators, and supports up to 230 W power delivery. AMD has given the 7950X and its sibling, the 7900X 12-core, a massive 170 W TDP, with 230 W PPT. The company recommends a 240 mm or 280 mm AIO liquid CPU cooler to go with these chips. Air-cooling won't cut it. The good news here is that AM5 maintains cooler-compatibility with AM4, so you're spoiled for choice with AM4-compatible liquid coolers.

The Ryzen 9 7950X comes with the highest clock speeds in the series, with a base frequency of 4.50 GHz, and a massive 5.70 GHz boost frequency, with all-core boost frequency spread above the 5 GHz-mark under acceptable cooling conditions. These processors are designed to run hot, and AMD claims that temperatures around the 95°C mark is considered "normal."

In our Ryzen 9 7950X review, we put AMD's new flagship through its paces, to see if AMD has restored the gaming performance lead, and by just how much its productivity performance has advanced. For this review, we've revamped our test-bench with many new benchmarks and game-tests, and we've retested dozens of processors, going several years back.

The Zen 4 Platform

AMD Zen has been one of the most remarkable turnarounds for a company in the semiconductor industry, and has had a profound impact on the consumer, as it influenced Intel's CPU core-counts. With each new generation of Zen, AMD delivered IPC and overall performance improvements, and Zen 4 stands out as it not only aims to improve performance, but also introduce a brand-new platform after five years of Socket AM4. As a parting gift, AMD enabled official Zen 3 support on even the oldest 300-series chipset, going to show just how consumer-friendly AM4 was, something the company hopes to repeat with AM5. The new AM5 socket was needed as the company enables the latest I/O, including DDR5 memory and PCI-Express Gen 5, besides power-delivery improvements. The socket can now deliver up to 230 W of power, which gives AMD room to increase CPU core-counts in the future. AM5 is a land-grid array, just like Intel desktop sockets, but the company somehow retained CPU cooler compatibility with AM4.

Zen 4 Chip Configuration

The Ryzen 7000 series desktop processor, codenamed "Raphael," is a multi-chip module, just like the Ryzen 5000 "Vermeer" and Ryzen 3000 "Matisse." The CPU cores are located in specialized dies called CCDs (CPU complex dies), while the platform I/O control is located in a separate die called cIOD (client I/O die). The CCDs were fabricated on the latest TSMC 5 nm EUV (N5) node, while the cIOD are done so on TSMC 6 nm (N6) nodes. The idea here is that the parts that benefit the most from the switch to the latest foundry process—the CPU cores—are built on this node; while everything else that can do with a slightly older node, is done so. This way AMD can make the most of its 5 nm foundry allocation with TSMC. The MCM contains a cIOD, and two 8-core CCDs in case of the Ryzen 9 7950X and 7900X; or one 8-core CCD in case of the Ryzen 7 7700X and Ryzen 5 7600X. Infinity Fabric interconnect handles communications not just within these dies, but also between them. The transition to fast DDR5 memory and PCIe Gen 5 means that AMD now can push instructions and data around faster. It did so with microarchitectural improvements to the "Zen 4" core itself, while increasing the Infinity Fabric bandwidth between the cores.

The Zen 4 CPU Core

All cores in Ryzen 7000 series processors are of the same kind, or what Intel would consider a performance-core, or P-core. AMD has worked on all three key stages of the CPU—the front-end, the execution, and the load/store. The front-end is the "mouth" of the CPU core, and prepares data and instructions for execution. Front-end improvements begin at the Branch Prediction unit, which can how predict 2 taken branches per clock-cycle, and comes with larger L1 and L2 branch-target buffers (BTBs). AMD had for the very first time introduced an OpCache with Zen, improving it over time. AMD has increased the size of the OpCache by around 68 percent. It can now handle 9 macro-ops per cycle. The micro-op queue dispatch rate to the execution stage is still 6.


The Execution Stage is the main number-crunching machinery, and broadly features two components for the kind of math workload being executed—Integer and Floating Point. The "Zen 4" execution stage features a 25% larger instruction retire queue, larger register files, and higher buffer queue-depths throughout the core.


With "Zen 4, "AMD is introducing support for AVX-512, in a bid to increase the processor's AI inferencing performance. The company did this in a die-area efficient, and energy-efficient manner, with no impact on CPU core frequency. AVX-512 operations are executed on a dual-pumped 256-bit FPU, rather than building ground-up 512-bit FP machinery. VNNI and Bfloat16 instruction-sets are also added, which mean that "Zen 4" can handle pretty much all of the AVX-512 client-relevant workloads that competing Intel processors can.


The Load/Store unit is the part of the core that interfaces with the memory sub-system. The "Zen 4" core gets a 22 percent larger Load Queue, with improved data-port conflict-resolution. There's a 50% larger L2 data transition lookaside buffer. The cache-hierarchy of the Ryzen 7000 desktop processor is similar to that of Ryzen 5000, with a few key differences, besides bandwidth/latency improvements—the dedicated L2 cache has been doubled in size to 1 MB. The eight CPU cores on a CCD share a monolithic 32 MB L3 cache, with uniform access to each core.


These improvements contribute to a 13 percent IPC improvement over "Zen 3," AMD claims. The company provided a break-up of which components are contributing to the IPC uplift, and we see that close to two-thirds of it are coming from improvements to the front-end and load/store stages. Branch prediction improvements contribute a fifth of this uplift. Interestingly, the L2 cache contributes barely 1/10th of the IPC uplift, in the tested applications—we believe this increase is mostly relevant for server applications where it should be able to make a difference. Intel's "Golden Cove" P-core comes with 1.25 MB L2 cache, and the upcoming "Raptor Cove" is expected to feature 2 MB. Despite the doubling in L2 cache sizes, the resulting increase in cache latency is very well contained (from 12 cycles on the 512 KB L2 of "Zen 3," to just 14 cycles on "Zen 4").


VBS (virtualization-based security) is the standard on new Windows 11 installs and gets activated automatically, unless you specifically disable it. Windows 11 Security Center already flags VBS not being enabled as a warning, similar to Antivirus being disabled or outdated. AMD made several improvements to the Virtualization feature-set, to reduce its performance impact in a VBS-enabled client environment. This includes speculation control, dual AVIC to go with the physical dual-APIC, and TSC_AUX virtualization.

New 6 nm IO Die

Ryzen 3000 "Matisse" and Ryzen 5000 "Vermeer" processors featured a cIOD built on the 12 nm FinFET Global Foundries node, but with Ryzen 7000 "Raphael", AMD is taking a giant leap toward improving the power characteristics of the cIOD, by building it on the new 6 nm TSMC node. This was needed mainly because the cIOD now packs an RDNA 2 iGPU, besides the higher bandwidth switching fabric of the DDR5 and PCIe Gen 5 interfaces also warranting the change. The 12 nm previous-gen cIOD TDP was already estimated to be up to 15 W, and the addition of an iGPU would've thrown things off gear. In addition to 6 nm, AMD is deploying several of the power-management features of the Ryzen 6000-series "Rembrandt" mobile processor on this cIOD, which mainly have to do with aggressive power management and rapid sleep/wake for the various components on the die.

The new 6 nm cIOD packs a dual-channel DDR5 memory controller (4x 40-bit channels, including ECC and hardware-accelerated encryption support), with native support for DDR5-5200; a PCI-Express 5.0 x28 root-complex; a USB 3.2 controller with support for 20 Gbps 2x2 ports, USB-C, and DisplayPort passthrough from the iGPU. AMD was very clear that the inclusion of an iGPU doesn't make "Raphael" an APU, because the iGPU is rather basic, and just about enough for non-gaming workloads. The company intends to continue making APUs—processors with beefy iGPUs for mainstream gaming performance—including for the desktop platform. Full ECC support on desktop is technically possible, but it will depend on the motherboard manufacturers—AMD isn't doing anything to prevent them from making their boards ECC compatible.


The Radeon 610 iGPU is based on the RDNA 2 graphics architecture, and packs just two Compute Units, which work out to 128 stream processors. The Display CoreNext (DCN) and Video CoreNext (VCN) components are of modern design. The VCN offers hardware-accelerated AV1 and H.265 decode, as well as hardware-accelerated H.265 encode. Just to clarify, there is hardware AV1 decode support, but no encode, which isn't a big deal at all. In terms of monitors, the DCN supports DisplayPort 2.0 UHBR10, HDMI 2.1 with FRL, and DisplayPort passthrough for the USB type-C ports connected to the on-die USB 3.2 controller. When paired with a discrete graphics card on Windows 10 or Windows 11, the iGPU supports Hybrid graphics, much in the same way as it's implemented on notebooks. You plug in your monitor to the iGPU, and it wakes up your discrete GPU (graphics card) when needed. The RDNA 2 compute units are of the same kind you'd find in Radeon RX 6000 series GPUs, including ray tracing support, but this is of no use on the Radeon 610. The only reason AMD went with RDNA 2 is because it can offer comparable levels of performance with just two CUs, to a "Vega" based iGPU that would need more CUs (thereby increasing die-size).


As we mentioned earlier, AMD needed a new socket as it was transitioning to DDR5 and PCIe Gen 5, which come with stiff physical-layer signaling requirements that AM4 couldn't provide. AM5 also makes processors "future-ready" as it enables two-way communication with the voltage regulators. The added pin-count was needed not just for DDR5 and its 40-bit sub-channels, but also for four additional PCIe lanes. The processor puts out a total of 28 PCIe Gen 5 lanes. 16 of these are meant for PEG (graphics card slots); 4 serve as chipset bus, and 8 lanes are available for the motherboard vendors to play around with: either wiring them both out as M.2 Gen 5 x4 slots, or wire one of them as M.2, and use the remaining 4 lanes for high-bandwidth devices, such as discrete USB4 controllers, 80 Gbps Thunderbolt 4 controllers, or even CPU-attached low-latency network interfaces. AM5 also significantly increases power-delivery capability over AM4—up to 230 W. The increased power should enable the "Zen 4" cores to run at very high clock-speeds approaching the 6 GHz-mark, or in the future, even enable core-count increases.


The clock-domains of Ryzen 7000 are similar to those of the Ryzen 5000 series. FCLK defines the Infinity Fabric clock-speed, which is de-linked from UCLK (memory controller clock), and MCLK (DRAM clock). AMD says that DDR5-6000 strikes the "sweetspot" in that this is the highest MCLK you can run while retaining certain memory overclocker optimizations. On Zen 3 you'd want to run Infinity Fabric in sync with memory, but this isn't possible anymore, because FCLK can't reach 3000 MHz (assuming DDR5-6000 memory). Now the optimum config is to run FCLK at 2000, basically a 3:2 divider. Picking "auto" in the BIOS will automatically aim for that setting. Above 6000 MHz, the strategy will be changed to 2:1 ratio.

AMD X670E and B650E Chipsets

AMD took a unique approach to chipsets with this generation. The top-tier chipset now comes in two flavors, X670E and X670. Both are identical in downstream I/O, but the X670E offers PCIe Gen 5 PEG besides CPU-attached Gen 5 NVMe; whereas the X670 only offers Gen 5 on the CPU-attached M.2 NVMe slot, but not PEG (which is Gen 4). A similar approach is taken when segregating the mid-tier B650E from the B650. The lack of Gen 5 PEG should significantly reduce motherboard costs, as designers would be saving on both Gen 5 redrivers and the steep wiring requirements to avoid signal-corruption.

X670E is a 2-chip chipset unlike the previous-gen X570. This was done to increase the downstream PCIe connectivity. The chipset now offers up to 12x PCIe Gen 4 and up to 8x PCIe Gen 3 downstream lanes (not counting the lanes from the CPU). This lets motherboard designers wire out three additional M.2 Gen 4 slots attached to the chipset, while the Gen 3 lanes handle low-bandwidth onboard devices. AMD adopted a wacky way to connect the two bridges that make up the chipset. There is an "upstream" chipset that's wired to the AM5 SoC over a PCI-Express 4.0 x4 connection; the second bridge is called "downstream" chipset, and is connected to four of the PCIe Gen 4 downstream lanes of the "upstream" chipset. The X670/E puts out up to two 20 Gbps USB 3.2, up to eight 10 Gbps USB 3.2, and twelve USB 2.0. The B650E and B650 look like more reasonable single-chip chipsets. They talk to the SoC over PCI-Express 4.0 x4, and wire out 8x PCIe Gen 4 downstream lanes, and up to 4x PCIe Gen 3 downstream lanes. You get half the number of USB SuperSpeed ports as the X670/E.

AMD EXPO Memory

With Ryzen 7000 series, AMD is introducing EXPO (extended profiles for overclocking); a feature that's identical in concept to Intel XMP. AMD EXPO-certified DDR5 modules come with an easy method of applying the advertised memory speeds and timings—you simply select a toggle in the opening screen of your motherboard's UEFI BIOS program. EXPO differs from XMP in that it includes fine settings that are unique to the AMD architecture, and it's also an open standard. Until now, XMP modules installed on AMD systems relied either on painstaking manual overclocking, or use of DOCP, a feature that attempts to translate the settings in the XMP profile to "nearest neighbors" of AMD-compatible settings. This was sub-optimal. EXPO is royalty-free compared to XMP, so any memory manufacturer can implement it for free. Ryzen 7000 can run any PC-DDR5 memory in the market, including XMP-certified ones, so don't fret if you can't find EXPO kits just yet.

Socket AM5

Here are a few pictures of Socket AM5, the star-attraction with this platform. This is a land-grid array (LGA) socket with 1,718 pins.


As with every LGA socket, the pins are on the motherboard, whereas the processor package has contacts that interface with those pins, while a retention brace holds the package in place with a locking lever. Installing a processor on AM5 is similar to doing so on any of the dozens of Intel LGA sockets.


On Socket AM4, removing the four mounting screws resulted in the backplate falling off, which meant you needed three hands when installing a cooler, and several vendors also bundled their own backplates. On Socket AM5 the backplate isn't designed to be removed, which makes cooler installation MUCH easier.


The caps for the socket are not identical to the Intel LGA sockets, so you can't reuse them.