AMD Zen 4 Ryzen 9 7950X and Ryzen 5 7600X Review: Retaking The High-End
by Ryan Smith & Gavin Bonshor on September 26, 2022 9:00 AM ESTSocket AM5: The New Platform for Consumer AMD
While the star for most CPU launches is typically the titular CPU, there’s a good argument to be had that for the Ryzen 7000 desktop launch, AMD’s overall platform warrants just as much attention, if not a bit more. After all, the company’s up-to-now current AM4 platform was introduced back in 2016, alongside Bristol Ridge, the last of the Bulldozers. A lot has changed for AMD in the last 6 years – not the least being the movement to the Zen core family – and now their underlying platform is getting a major overhaul as well.
The first new consumer platform and associated socket designed by AMD since the start of the Zen era, AM5 is designed to bring three major updates to AMD’s desktop ecosystem. These can be roughly broken down as improving power delivery, adding DDR5 memory support, and boosting the amount of bandwidth and flexibility for I/O devices downstream of the CPU. All three of these things require (or at least are best accomplished) with CPU pin changes, so this is AMD’s first chance in 6 years to overhaul everything that flows in and out of their desktop CPUs.
Socket AM5
Physically, the most obvious change is of course the socket itself. AMD held on to using pin grid array (PGA) sockets for its mainstream consumer platforms for over a decade after Intel made the switch to land grid array (LGA), but now with AM5 the company is making the switch as well.
As was the case when Intel switched, the shift to LGA brings a couple of benefits, and a couple of trade-offs. Overall LGA allows for greater pin density; whereas socket AM4 was 1331 pins, socket AM5 is 1718 pins in the same package size. This switch also means that the relatively vulnerable pins are moved from the CPU package to the motherboard, which is modestly safer overall. The good news is that this means the days of trying to fix pins on an AMD CPU with a mechanical pencil are coming to an end; the bad news is that if LGA pins are damaged, the motherboard is essentially done for.
This also means that AM5 gets the vastly improved retention mechanisms required by LGA setups, as opposed to the zero-insertion force (ZIF) sockets of the last 30+ years. So CPUs are now much more securely locked down into their sockets, and the errant cases where trying to pull off a cooler and having the CPU come with it is no longer a possibility.
It’s notable here that AMD’s new socket actually has slightly more pins than Intel’s current LGA-1700 socket, at 1718 vs. 1700. Though sharp-eyed power users will note that Intel and AMD have pretty distinct pin configurations (never mind package sizes), with Intel reserving a decent amount of the of the pin pad for placing capacitors and other electronics on the underside of the CPU package, whereas AMD has placed everything on top.
But despite the significant changes in CPU sockets, AMD has worked to preserve backwards compatibility with standard socket AM4 coolers. This is part of the reason for AM5 chips’ odd heatspreader layout, and while I have some personal misgivings about keeping the clips around, there’s no arguing that it will help get the AM5 ecosystem immediately bootstrapped, as it won’t require entirely new coolers. With that said, this compatibility does not extend to coolers that need to replace the stock AMD backplate, so the compatibility rate is not 100%. Builders looking to reuse an old cooler in a system upgrade will want to look into matters to make sure that their cooler is indeed compatible with AM5.
AM5 Power Delivery: Higher Limits & SVI3 Power Management
A big portion of AMD’s new pin budget for AM5 has, in turn, been invested into power delivery. The AM4 platform was designed for CPUs at TDPs up to 105W – or more specifically, a maximum socket power of 142W. As seasoned overclockers already know, this isn’t a hard limit and it’s long been possible to drive more power than this through AM4. But doing so does exceed the design parameters of the socket, the trade-offs of which aren’t advisable for commercial off-the-shelf systems that may need to be supported for several years.
So for AM5, AMD has significantly increased the maximum power they can drive through their socket. The official TDP limit is 170 Watts, which maps out to a total socket power of 230 Watts, a 62% increase in stock power limits. And AMD is going to be taking full advantage of these higher power limits right out of the gate, with the Ryzen 9 7950X and other high-end processors slated to ship with 170W TDPs. In fact this is where a significant chunk of the multi-threaded performance gains from the new Ryzen chips are coming from, as previously AMD’s highest core count CPUs were TDP-constrained when trying to light up all of those cores.
| Stock AMD Socket AM5 TDP Groups | |||||
| 65W TDP | 105W TDP | 170W TDP | |||
| Socket Power (PPT) Watts | 88W | 142W | 230W | ||
| Peak Current (EDC) Amps | 150A | 170A | 225S | ||
| Sustained Current (TDC) Amps | 75A | 110A | 160A | ||
Do note that this also means that cooling requirements are going up. For their 2 CCD parts with 170W TDPs, the 7900X and 7950X, AMD is outright recommending a 240mm (or larger) AIO cooler for keeping those chips under control. AMD only suggests tower coolers for the 1 CCD parts, as these have the same 105W TDP as AMD's former top-end AM4 parts. With that said, this doesn't mean an air cooled setup isn't going to be viable with the higher TDP parts, but you will definitely need a good air cooler if you want to keep ahead on dissipating all of the heat a fully loaded 16C processor can produce.
And while AMD’s peak power consumption is going higher, AMD is also implementing additional technologies to better manage power consumption, and to keep their chips from fully ramping up unless they need to. The big change here is that AMD has ported a lot of their power savings technologies from the Ryzen 6000 Mobile family over to the AM5 platform (and Ryzen 7000 IOD), most notably Scalable Voltage Interface 3 (SVI3), which as in the case of the mobile parts, is designed to allow faster and more discrete control over the voltage required from the chip.
SVI3 is a high-speed, 2-way communications protocol between the CPU and the voltage regulators, allowing the CPU to not only better direct the increasingly large number of VRM phases on high-end motherboards, but to keep an eye on VRM health, monitoring things such as power delivery and VRM temperature. This allows an AM5 CPU to make better and more aggressive decisions about power management, as opposed to having to make more conservative assumptions about the state of the VRMs.
Of particular note here, these upgrades allow for a larger number of overall power states the CPU can be in, which in turn allows for more optimal use of the VRMs. For example, this allows automatic phase shedding to shut off some of the VRM phases feeding the CPU when they’re not needed, which boosts the overall power efficiency of the system (extra phases are great when you need a lot of power, but waste power themselves at low loads).
Altogether, AM5 supplies CPUs with 3 variable power rails, which is up from the 2 rails supplied by AM4. The CPU cores and graphics cores get a shared rail, and there’s a separate SoC rail to power most of the rest of the IOD. Finally, there’s a miscellaneous VDD rail that provides power to the GMI/Infinity Fabric interconnects, along with some other, smaller IPs. Separate from that, there are still fixed rails for things like the memory, 3.3v rail, etc.
Native BIOS Flashback Support
With AMD slated to support the AM5 platform through at least 2025, this time around the company is more actively planning around the future of the platform. In particular, AMD is taking a stab at motherboard forward compatibility, which was increasingly an issue for AM4 over its six-year reign.
The big breaker there was that, even when supported by the chipset, older boards required newer BIOSes to support newer generations of CPUs. Thus the only way to make an old board work with a newer CPU was to flash it with a newer BIOS, which in turn required a working CPU to begin with – a catch 22 situation that ultimately resulted in AMD developing a loaner kit program which rented out older AM4 CPUs that customers could use to flash their older boards if they didn’t already have a new CPU for it (e.g. they just bought it off the shelf).
Ultimately, the more elegant solution to the problem is to allow BIOS flashing without a working CPU (or BIOS), which does an end-run around the whole problem. That exists today in the form of USB BIOS Flashback features; however flashback has been a motherboard-level feature that’s normally only found on select high-end motherboards and has to be implemented by the motherboard vendor itself. So for the AM4 generation, it was not a universal (or even widely available) option.
For the AM5 platform, AMD is taking matters into their own hands to make USB BIOS Flashback a universal feature. Ryzen 7000 chips will be able to support USB BIOS Flashback mode across the board and regardless of the BIOS currently installed. As a result, users will always be able to flash an updated BIOS to their AM5 boards, regardless of the CPUs supported by or the operational status of the current motherboard.
The net impact is that when AMD releases future chips on the AM5 platform – say, a Zen 5 chip in 2024 – it will be possible to install a compatible BIOS without first having to use a Zen 4 chip. Though this does assume, of course, that Zen 5 chips will work in current X/B-600 series boards, which is likely but should not be taken as a given. Otherwise, this change also offers a moderate improvement to the reliability of the AM5 platform, by making it so that the BIOS on any board can be restored should it end up corrupted for whatever reason.
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emn13 - Monday, September 26, 2022 - link
The geekbench 4 ST results for the 7600x seem very low - is that benchmark result borked, or is there really something weird going on? Replyemn13 - Monday, September 26, 2022 - link
Sorry, I meant the geekbench 4 MT not ST results. The score trails way behind even the 3600xt. ReplySilver5urfer - Monday, September 26, 2022 - link
Good write up.First I would humbly request you to please include older Intel processors in your suite, it will be easier to understand the relative gains for eg the old 9th gen, 10th gen as a reliable place I see things all over on other sites, AT is at-least consistent so would be better if we have a ton of CPUs in one spot. Thanks
Now speaking about this launch.
The IOD is now improved by a huge factor so no more of that IF clock messing with the I/O controller and high voltage on the Zen 3 likes it's all improved so I think the USB fallout issues are fixed on this platform now. Plus the DP2.0 on iGPU is a dead giveaway on RDNA3 with DP2.0 as well.
IMC is also improved looking at it AMD operated with synchronized clocks with DRAM now they can do it without that since IF is now at 2000MHz and the IMC and DRAM are higher at 3000MHz to match the DDR5 data rates. Plus the EXPO is also lower latency, however the MCM design causes the AIDA benchmark to have high latency vs Intel even though Intel is operating at Gear 2 ratio with similar Uncore decoupled. Surprisingly the inter core latencies did not change much, maybe that's one of the key to improving more on AMD side gotta see what they will do for Zen 5.
The CPU clocks are insane, 5GHz on all 16C32T is a huge thing, plus even the 7600X is hitting 5.4GHz. Massive boost from AMD improving their design, plus the TSMC5N High Performance node is too good. However AMD did axed their temps and power. It's a very good move to not castrate the CPU with power limits and clocks now that's out it gets to spread it's wings. But the downside is, unlike Intel i7 series Ryzen 6 also gets hot meaning the budget buyers need to invest money in AIO vs older Zen 3 being fine on Air. That's a negative effect for AMD when they removed the Power Limits like Intel and let these rip to 250W.
Chipset downlink capping at PCIe4.0x4 was the biggest negative I can think of it, because Intel DMI is now 4.0x8 on ADL and RPL, RKL had it at 3.0x8 CML at 3.0x4. AMD is stuck to 4.0x4 from X570. Many will not even care, but it is a disadvantage when you pay top money for X670E they should have given us the PCIe5.0x4, AMD will give that in 2024 with Zen 5 X770 chipset that's my guess.
The ILM backplate engineering is solid that alone and the LGA1718 AM5 longevity itself is a major PLUS for AMD over LGA1700's bending ILM and EOL by 13th gen. Yes the 12th gen is a better purchase given how the Cooling requirement for i7 and i5 is not this high like R6 and R7 and the cheaper board costs plus 13th gen is coming and AMD's platform is new as well you would be a guinea pig. Depends on what people want and how much they can spend and what they want in longevity.
Performance is top notch for 7600X and 7950X absolute sheer dominance but the pricing is higher when you see the % variance vs Zen 3 and Intel 12th gen parts, and added AIO mandatory because they are hot. The gaming performance is as expected not much to see here and the 5800X3D still is a contender there but to me that chip is worthless as it cannot match any processor in high core count workloads. Although 7600X is a champion 6C12T and it beats 12C24T in many things and the 10C20T 10th gen Intel too. IPC is massive in ST and MT workloads as expected. AMD Zen 4 will decimate ARM, Apple has only one thing lol muh efficiency all that BGA baggage, locked down ecosystem is free.
RPSC3 perf at TPU's Red Dead Redemption is weird as I do not see any gains over Intel, given how much of a beast this AVX512 is on Zen 4 with 2x256Bit without AVX offset that too maybe they are not using AVX512. Plus their AMD Zen 3 gauging is also bad because they do not work well vs Intel 9th gen even, I wish you guys cover Dolphin emu, PCSX2, RPCS3 and Switch Emulators.
I think best option is to wait for next year and buy these parts as they will drop, right now no PCIe5.0 SSD in high capacity. no PCIe5.0 GPU even that Nvidia skimped on it. No use of the new platform unless one is running a super damn old CPU and GPU setups.
Shame that OC is totally dead, Zen 3 was hamfisted with its Curve Optimizer and Memory tuning becoming a head ache due to how AGESA was handled and the 1.4v high voltage and lack of documentation. Zen 4 it's even 1.0-1.2v still no OC because AMD's design basically is now pushed to maximum with it's Core TJMax temps and how it works on the basis of Core temperatures over everything else. There's no room here, AIO is saturated with 90C here. Too high heat density on AMD side similar to Intel 11th and 12th gen. Although Intel can go upto 350W and hit all cores at higher vs AMD 250W max. Well OC was on life support, only Intel is basically keeping it alive at this point after 10th gen it became worse and 12th very hot and high heat and now 13th gotta see if that DLVR regulator helps or not.
All in all a good CPU but has some downsides to it. Not much worth for existing 2020 class HW folks at all. Better wait when DDR5 matures even further and more PCIe5.0 becomes prevalent. Reply
Threska - Monday, September 26, 2022 - link
Maybe people will start delidding.https://youtu.be/y_jaS_FZcjI Reply
Silver5urfer - Tuesday, September 27, 2022 - link
That Delid is a direct die, it will 100% ruin the AM5 socket for longevity and the whole CPU too. That guy runs HWBot, ofc he will make a video on his bs delid kits. Nobody should run any CPU completely blowing the IHS off. You will have a ton of issues with that. Water leak, CPU silicon die crack due to Thermodynamics and the pressure differences over the time, Liquid Metal leak. Total bust of Warranty on any parts once that LM drops on your machine game over for $5000 worth rig there.AMD should have done some more improvements and reduced the max TJ Max to say 90 at-least but it's what it is unfortunately (for high temps and cooling requirements) and fortunately (to have super high performance) Reply
Threska - Tuesday, September 27, 2022 - link
There are some in the comments both wondering if lapping would achieve the same and the thicker lid was giving some room for future additions like 3D cache, etc. Replyabufrejoval - Wednesday, September 28, 2022 - link
I'm not sure that PCIe 4.0 "DMI" downlink capping is a hard cap per se by the SoC, but really the result of negotiations with the ASmedia chipset, which can't do better. I'd assume once someone comes up with a PCI 5.0 chipset/switch, there is no reason it won't do PCIe 5.0. It's just a bunch of 4 lanes, that happen to be connected to ASmedia PCIe 4.0 chips on all currrent mainboards.Likewise I don't see why you couldn't add the second chipset/switch to the "NVMe" port of the SoC or any of the bifurcated slots: what you see is motherboard design choices not Ryzen 7000 limitations. That just has 24 PCIe 5.0 lanes to offer in many bundle variants. It's the mainboard that straps all that flexibility to slots and ports.
I don't see that you have to invest into AIO coolers, *unless* you want/need top clocks on all cores. E.g. if your workloads are mixed, e.g. a few threads that profit from top clocks for interactive workloads (including games) and others that are more batch oriented like large compiles or renders, you may get maximum personal value even from an air cooler that only handles 150 Watts.
Because the interactive stuff will rev to 5.crazy clocks on say 4-8 cores, while for the batch stuff you may not wait in front of the screen anyway (or do other stuff while it's chugging in the background). So if it spends 2 extra hours on a job that might take 8 hours on AIO, that may be acceptable if it saves you from putting fluids into your computer.
In a way AMD is now giving you a clear choice: The performance you can obtain from the high-end variants is mostly limited by the amount of cooling you want to provide. And as a side effect it also steers the power consumption: you provide 150 Watts worth of cooling, it won't consume more except for short bursts.
In that regard it's much like a 5800U laptop, that you configure between say 15/28/35 Watts of TDP for distinct working points in terms of power vs. cooling/noise (and battery endurance).
Hopefully AMD will provide integration tools on both Windows and Linux to check/measure/adjust the various power settings at run-time, so you can adjust your machine to your own noise/heat/performance bias, depending on the job it's running. Reply
Dug - Monday, September 26, 2022 - link
"While these comments make sense, ultimately very few users apply memory profiles (either XMP or other) as they require interaction with the BIOS"This is getting so old. Your assumption is incorrect which should be obvious by the millions of articles and youtube videos on building computers. Not to mention your entire article is not even directed to "general public" but to enthusiasts. Otherwise why write out this entire article? Just say you put a cpu in a motherboard and it works. Say it's fast. Article done.
Why not test with Curve Optimizer? Reply
Oxford Guy - Tuesday, September 27, 2022 - link
This text appears again and again for the same reason Galileo was placed under house arrest. Replysocket420 - Monday, September 26, 2022 - link
Could someone, preferably Ryan or Gavin, please elaborate on what this sentence - "the new chip is compliant with Microsoft’s Pluton initiative as well" - actually means? This is the only review I could find that mentions Pluton in conjunction with desktop Zen 4 at all, but merely saying it's "compliant" is a weird way of wording it. Is Pluton on-die and enabled by default in Ryzen 7000 desktop CPUs? Reply