Comment by Danieru

> Different x86 micro-architectures benefit from writing the machine code in slightly different ways. Games are highly optimized to the specific micro-architecture of the console, so keeping that stable helps game developers optimize for the console.

While that can be true, very few gamedev companies these days optimize to that degree. They almost all use off-the-shelf middleware and game engines that are built to support all of the platforms. The companies that do go through that effort tend to have very notable releases.

Nobody is hand-tuning Assembler code these days to fit into tight instruction windows. At least, not outside of some very specific logic fragments. Instead they're all writing generic interrupt-based logic. Which is fine, as that's what the newer CPUs expect and optimize for internally.

In addition, the difference in the Zen generation gap is as different as switching to Intel. We're talking fairly different cache coherency, memory hierarchies, CCX methodologies, micro-op and instruction timings, iGPU configurations, etc.

That all being said, AMD was going to beat Intel regardless because of established business relationships and their current internal struggles (both business-wise and R&D) making it fairly difficult for them to provide an equivalent alternative.

> An important non-obvious detail for AMD is that they (at least in the past, I assume for this as well) have kept the instruction timings similar from generation to generation of consoles.

What? The Jaguar-based CPU in the PS4 has both a much lower clock and substantially lower IPC than the Zen 2 based one in the PS5. The timings are not remotely the same and the micro-architectures are quite different. Jaguar was an evolution of the Bobcat core which was AMD's answer to the Intel Atom at the time (i.e. low cost and low-power, though it was at least an out-of-order core unlike contemporary Atoms).

Going from GCN to RDNA on the GPU side is also a pretty significant architectural change, though definitely much less than the going from AMD to Intel would be.

you clearly haven't played a modern game :P

cpu timings taken care around by developers is 10-15 years out of date. most of them these days dont even know what a dot product is, how to find the distance to a point or a straight line in-between two... and the people they rely on to do this for them make horrendous meals of it.

but yeah, sure, cpu instruction timings matter.

Given the size of such a contract, wouldn't it be reasonable for Sony to just request equal or better instruction latency for everything relevant from the old CPU?

Sometimes a low margin business is all you need and have to keep the lights on, don't hemorrhage too much people and stay afloat until you get better winds.

Traditional MBA thinking sometimes is too short sighted. For example, PCs might not have been a Cash Cow for IBM, but the Thinkpad brand, the distributor relationships and the customer may had helped IBM more than the cash out selling this business to Lenovo. Maybe having a healthy bridge head with a popular brand of laptops could have helped IBM coming up with some innovative way of selling the overhyped Watson.

The same with AMD and videogames, it paid the bills, paid salaries and left a little profit on the table to be invested. Probably it helped them bridge from their hell days to what they are today.

There's a lot of intangibles and hidden symmetries, serendipitous opportunities that are frequently overlooked by our bean-counting master race overlords.

> Xbox and Playstation dont earn AMD much profits at all

It doesn't cost them much either. Lisa Su, in an interview that was posted to HN a few months ago, said it is a deliberate strategy to repackage IP AMD has already developed. They are willing to pull designs from the shelf and customize it to meet partners needs. Having a long tail of products adds up, and sets you up to get first dibs on higher margin partnerships in the future.

> Nvidia got the bid for Switch when they were basically dumping those unwanted Tegra to Nintendo for an incredibly low price.

This seems pretty well aligned with Gunpei Yokoi’s strategy of “Lateral Thinking [with] Withered Technology”. It worked out pretty well for Nintendo in the past (e.g., Gameboy) and seems to be working out with the Switch. Even though he has passed, his Wikipedia page alleges that this philosophy has been passed on to others at Nintendo.

A few of the Playstation titles that made their way to PC do seem to have a little home field advantage on AMD chips, but not enough to sway people over to them.

> having AAA titles on Xbox and PS would have helped AMD's market share on PC, given those titles are already optimised on Xbox and PS anyway. That didn't happen at all. And Nvidia continue to dominate.

My impression is that console ports have insufficient popularity with PC gamers for them to alter their hardware purchasing habits for those games.

For GPU emulation, I'm not super knowledgeable but I would think the shaders are a big issue, older systems don't have that problem. Console games come with precompiled shaders and you won't be able to reuse those between AMD vs. Nvidia. Certainly you can get around it, emulators for modern Console do just that, but it's not without it's issues which might be considered unacceptable.

That's still fixable if you're willing to ship newly compiled shaders and such, but that's a lot more work if you're talking about needing some kind of per-game fix to be downloaded. This is how the XBox 360 "Backwards-compatibility" works, and this approach means it only works with a subset of XBox 360 games, not all of them. It's much better than nothing, but it's not a hardware-level fix that makes the original game binaries "just work".

For packaging the old GPU with the new system, I think that's not really realistic anymore since prices for them simply don't drop enough and the system design would be a mess (the chips are huge and you'd need cooling for both chips. I guess if only one is running at a time then it's not as bad, but...). Separately, if you're swapping from Nvidia to AMD then you're talking about trying to convince one of them to make a batch of old chips for you while you use their competitor's chip as the the main one, they might not be willing to do it.

Microsoft maintained backwards compatibility across Intel+Nvidia, IBM+ATI, and AMD+AMD so it's possible. Sony hasn't invested as much in compatibility, instead just keeping the same architecture for PS4/5.

There was no backwards compatibility between the PS3 and PS4 whatsoever (except for PS Plus allowing cloud-based game streaming of some PS3 titles), and Sony survived that as well.

What they did was offer some old PS2 games for purchase, though, which allowed them to tap into that very large back catalog. I could see something like this happen for a hypothetical Intel PS6 as well (i.e. skipping PS5 backwards compatibility and tapping into the large catalog of PS4 and PS4/PS5 games).

I am quite sure PS5 doesn't do Vulkan at all, and you even don't need a NDA access for that, there are enough GDC talks and SCEE presentations on the what APIs Playstations do support.

It’s not clear to me that the PS5 supports Vulkan at all (excluding third party translation layers). I would be happy to see any evidence. In any case I’m confident the large majority of PS5 games use its native api GNM.

GNM could certainly be implemented for Intel GPUs, but it’s an additional cost to account for.

> At this point Nintendo is skewed towards ditching (SNES/N64/Gamecube/Switch vs. Wii/WiiU).

Ultimately, a company is its people. And the management class at Nintendo is famously new. Everybody is expecting them to focus on robust backwards compatibility as part of their new, exciting development.

> Whereas I imagine the PS6 being a "PS5 Pro Pro" at this rate.

I think there will be sufficient time between now and PS6 release that they will be able to support full RTRT.

> Yeah, this was rigged from the start. If Sony did want to take up Intel next gen, they'd need to do a lot of work on backwards compatibility with the PS5 on the PS6. Whereas I imagine the PS6 being a "PS5 Pro Pro" at this rate.

Why would they need to do a lot more work on compatibility if they'd picked Intel vs AMD?

Either CPU is presumably going to be x86_64. The GPU is almost certainly going to be much different between AMD's PS5 GPU and AMD's PS6 GPU, so the graphics driver will need work either way.