The Rise and Fall (and Rise Again) of AMD
Less than half a decade ago, if you had walked up to someone in the industry and said that in 5 years’ time AMD would have the fastest CPUs, you would have been laughed straight out of the room—but here we are. At the time of writing, AMD does have the fastest CPUs on the market with Zen 3 [1], so let’s see where AMD is heading in the future.
It’s not a controversial statement for me to say that the Bulldozer family of CPUs was a failure. Not just a commercial failure in a period that eventually saw AMD nearing bankruptcy, but also a technical failure. There are however parts of the Bulldozer core that are good such as the FPU and branch predictor unit. Weaknesses in its shared front-end and poor cache/memory systems meant a 4-module Bulldozer CPU lost to a 4-core Sandy Bridge CPU in most workloads, despite the higher clocks. Insult to injury for AMD was the the fact that a 4-module Bulldozer CPU also consumed more power than a 4-core Sandy Bridge CPU while being slower—in short the architecture was almost universally panned.
Thankfully for AMD, when the original Zen architecture released in Q1 2017 it finally showed they weren’t out of the CPU game. Zen 1 had an extremely bullish 40% IPC increase design goal over Excavator and ultimately delivered an unheard of 52% IPC gain. AMD was back. Following up with Zen 2 and Zen 3, though they were not the same monstrous uplifts as Zen 1, they represented a respectable 15% and 19% IPC gain over their predecessors respectively. But y’all know that already, so let’s talk about the future of AMD’s CPUs.
Zen 3+, Zen 4, and Beyond
AMD looks poised for even more continued success with Ryzen, assuming of course that the information and sources that both I and the rest of Chips and Cheese’s staff have access to are accurate. Please take all the following information in this section with the usual cautionary dose of salt. While both the Chips and Cheese team and I have full belief that this information is accurate, that does not mean that this is 100% confirmed and you should not take this as unsalable truth [1].
Zen 3+ looks to be a small IPC gain on base Zen 3, having been told “It’s more than Zen+ was [over Zen 1] but not much” which I interpret to mean around a 4 to 7% IPC gain along with customary clock gains moving to the smaller N6 node from TSMC. N6 is a variant of N7 using 5 layers of EUV and is not a true “new node”, more of a refinement. However, the most interesting thing to me is that Zen 3+ on desktop may be the first AM5 CPU. I was told that the IO die for Zen 3+ desktop is using “Not quite [the same] IOD as Zen 4 but uses Zen 4 IP” which I take to mean that it will be using DDR5 and it will be on the same node as Zen 4’s IOD.
Now, on to the main event—Zen 4. Zen 4 is what a lot of people are waiting for, and, if the info I have is accurate, that wait will prove to be even more worth it. It is important to note that the one common thread in all Zen 4 chatter I have heard is resounding positivity. From IPC gains over 25%, a total performance gain of 40%, and even possibly (finally) 5GHz all-core thanks to the new (full node) N5 fabrication at TSMC! [1] Now, I can’t say what is true and what is an over-exaggeration, however I was told from a trusted source that a Genoa engineering sample (Zen 4 server chip) was 29% faster than a Milan (Zen 3) chip with the same core config at the same clocks. Factor this in with what I have heard about the possible clock gains that N5 will enable over N7 and Zen 4 sounds like it is going to be a monster of a CPU.
But wait, there’s more! I also have some juicy info on Zen 5. Now, this comes from a different, less-proven source than my Zen 4 info, however they have said that the jump [to Zen 5 from 4] will be about as much as Piledriver to Zen 1 design goal, which if you recall to earlier in this article was 40%. [2] I was told from a 3rd source that Zen 5’s original design goal was 2.5 to 3 times the IPC of Zen 1 which roughly lines up with the perspective of a “Piledriver to Zen 1”-like jump. If this info is all true, then that puts AMD in a very good position from a performance standpoint.
Potential Roadblocks Ahead
However, the biggest problem for AMD of late hasn’t been one of performance but of wafer supply. With Apple moving off of Intel CPUs and onto their own silicon for (gradually) their entire lineup, the supply of N5 wafers from TSMC for AMD will be less than if Apple had stuck with Intel. Being that AMD is always 2nd in line for new nodes at TSMC behind Apple, this may be a cause for concern moving forward. [3]
Perhaps an even bigger factor for availability on TSMC N5 will be that neither future AMD CPUs nor GPUs will need to compete with console chips as they will remain on N7. Couple this with the rumors that AMD GPUs are also going MCM with RDNA3, and it is possible that Zen 5 and RDNA 3 supply will be better than what we know of the current shortages for Zen 3. [4] This is especially important for the GPU side seeing the current availability issues around RDNA2; the wafer allocation of which has been said to represent low-single digits of TSMC’s N7 supply. [5]
Conclusion: A Bright Future Ahead, With Some Caveats
One thing is certain however: AMD’s future looks bright. There was a miscommunication between myself and the editor with regards to the performance claims of Zen 4. The only thing that we are claiming with any level of certainty is the claim of a Genoa ES sample being 29% faster then Milan at the same clocks. We apologize for any confusion this may have caused. [1]
Despite the potential supply chain challenges, the technological advancements in AMD’s Zen roadmap are undeniably impressive. From the respectable IPC gains in Zen 3 to the rumored monster leaps in Zen 4 and Zen 5, it’s clear that AMD is once again poised to shake up the CPU market. Of course, as with any unconfirmed information, we’ll have to wait and see how it all plays out. But if AMD can deliver on even a fraction of these performance claims, the future of Ryzen is looking brighter than ever before.
References
[1] Chips and Cheese. (2021, February 5). AMD’s Past and Future CPUs. https://chipsandcheese.com/2021/02/05/amds-past-and-future-cpus/
[2] Reddit. (2021, April 14). AMD Ryzen 9000 (Zen 5) CPU Specs and Launch. https://www.reddit.com/r/Amd/comments/1ad143h/amd_ryzen_9000_zen_5_cpu_specs_and_launch/
[3] GamesRadar. (2022, January 4). AMD Ryzen 7000: Everything we know. https://www.gamesradar.com/amd-ryzen-7000-everything-we-know/
[4] Reddit. (2022, November 12). How to cripple Zen 4 in gaming benchmarks. https://www.reddit.com/r/hardware/comments/112up15/how_to_cripple_zen_4_in_gaming_benchmarks_amd_zen/
[5] PC Gamer. (2022, January 5). AMD Zen 4 Ryzen 7000: Our first glimpse. https://www.pcgamer.com/amd-zen-4-ryzen-7000-first-glimpse-ces-2022/
[6] Framework Community. (2022, November 13). AMD 13 – Hopelessly Outdated. https://community.frame.work/t/amd-13-hopelessly-outdated/41572
[7] Overclock.net. (2022, January 20). AM5 Future RAM Speed Support. https://www.overclock.net/threads/am5-future-ram-speed-support.1803198/
[8] TechPowerUp. (2022, February 1). AMD Ryzen Interview: AI, Zen 4, Strategy. https://www.techpowerup.com/review/amd-ryzen-interview-ai-zen-4-strategy/4.html
