Had x86_64 not been released, I also think we'd see a more diverse set of serverside chips as well, such as SPARC and POWER. There wouldn't have been an obvious dominance in the marketplace of a single architecture.

Also, had it not been released, we'd probably have seen a larger fracturing of the laptop CPU market with a broader switch to ARM64.

In a sense, because AMD forced Intel's hand in supporting x86_64, they actually helped Intel have even more dominance in the market with an architecture that spans laptops to server work horses. We developers barely need to lift a finger in targeting either.

If amd64 had not been released, I think itanium would probably own the server market. But it would be a very different server market .. much more like the late 90s market than today's market.

Remember that Intel was twisting arms and making deals to kill the weaker RISC chips in the marketplace. In the leadup to the first Itanium, HP had acquired Compaq (which had acquired DEC), so they held both Alpha and PA-RISC. And SGI was still a fairly big player with mips64. Both HP and SGI made deals to use Itanium going forward (with HP going so far as to port HP-UX and VMS to Itanium).

I think the server marketplace would probably have been much higher margin without amd64 competition, as itanium was always a high margin player. Its main competitors were the high margin server chips above, plus POWER and SPARC. The low end was x86 controlled by intel, and they could certainly continue to artificially segregate the market and keep margins high. That's what they were good any monopoly does, and what they've been trying to do today with Xeons.

I was a huge fan of Alpha (one of 2 people who ported FreeBSD to the alpha), and I was very sad to see it go. I've always blamed Itanium for its downfall -- I think Alpha had a lot more headroom than PA-RISC, and HP would have kept it going if it were not for Itanium. So I have to admit that I'm quite happy to see Itanium die.

Hey, thanks for your work on the FreeBSD alpha port! We got a lot of mileage out of it, while pointing and laughing at Itanium the whole time :)

It's also interesting to think about what would have happened if Rick Belluzzo hadn't been in the right place to convince both HP (as a VP) and then SGI (as CEO) to make large bets on Itanium and Windows. I don't think the market would have supported that many more expensive CPUs – fab economics are brutal – but two of the major players giving control over key parts of their design to Intel & Microsoft significantly accelerated that trend.

SGI is interesting because they _owned_ the 3D space and shortly before he went to Microsoft, SGI gave nVidia and Microsoft very cheap licenses to their extensive collection of patents and other IP. It's interesting to imagine what might have happened if, say, SGI had switched to Intel but with fewer gambles on unproven technology: x86 and Linux or the internal IRIX x86 port instead of Itanium and the heavily modified Windows NT derivative which was very expensive to support and forced all of their developers to make massive code changes. Similarly, they were focused on the high-end 3-D market (engineering, science, animation, etc.) and dismissed the PC gaming business as insignificant and basically gave it to nVidia along with a bunch of their staff; had someone a little short-sighted been involved that would have made a big difference in their bottom line.

I dunno. The cost advantage of x86-64 plus Linux and Windows was a tough nut for other RISC vendors to beat. Price/Performance, plus general support. For example, x86-64​ servers could get away without SSL acceleration because the handshake was done in optimized ASM for most web servers. For other architectures, it wasn't.

What makes you think it wouldn't have been POWER? Or SPARC? They were both way more popular than PA-RISC.

Because Power and Sparc would have ceded to Itanium. Neither backer had the resources Intel did. The easy path to kill Itanium was x86-64, because it was inexpensive and worked with Linux and Windows. AMD didn't have to compete with Intel per se. It forced Intel to do X86-64 as well...which killed Itanium.

If I had to bet on the reason of Itanium failure, I would also choose AMD64. But not because it was cheap, but because it had x86 in the name. For some reason whenever Intel tried to abandon x86, they failed, like Itanium, i960, XScale.

Perhaps. At least where I was, though, it was the cost factor. We liked Solaris better than Linux. But big Solaris Sparc servers (and every other RISC server too) were 6 figure purchases, with accompanying big support contracts. A high end 4 way x86-64 box was much lower initial cost, and much lower recurring cost. They did start lowering prices when they saw the shift, but too little, too late.