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What I find interesting is that Intel engineers actually designed their own 64-bit extension, somewhere along the same lines as AMD64. Intel's marketing depart

• p_l 7mo ago
  Around the time of K8 being released, I remember reading official intel roadmaps announced to normal people, and they essentially planned that for at least few more years if not more they will segment into increasingly consumer-only 32bit and IA-64 on the higher end
  • twoodfin 7mo ago
    Itanium was bonkers in lots of ways—very cool in others. But this market segmentation idea just seems absolutely insane to me in a way I’ve never had anyone satisfactorily explain. It requires Intel to voluntarily destroy the commodity economics that put their CPUs on a rocket ship to domination. It’s as if they actually bought into the RISC FUD from the 1990’s that x86 was unscalable, exactly when it was taking its biggest leaps.
    • rob74 7mo ago
      Well, TBH it wasn't all FUD - hanging on to x86 eventually (much later) came back to bite them when x86 CPUs weren't competitive for tablets and smartphones, leading to Apple developing their own ARM-based RISC CPUs (which run circles around the previous x86 CPUs) and dumping Intel altogether.
      • SonOfKyuss 7mo ago
        It is interesting how so much of the speculation in those days was about how x86 was a dead end because it couldn’t scale up, but the real issue ended up being that it didn’t scale down.
        • rob74 7mo ago
          Well, it turns out that it could scale up, it just needed more power than other architectures. As long as it was only servers and desktop PCs, you only noticed it in more elaborate cooling and maybe on your power bill, and even with laptops, x86 compatibility was more important than the higher power usage for a long time. It's just when high-performance CPUs started to be put in devices with really limited power budgets that x86 started looking really bad...
    • AdamN 7mo ago
      They were trying to compete with Sun and IBM in the server space (SPARC and Power) and thought that they needed a totally pro architecture (which Itanium was). The baggage of 32-bit x86 would have just slowed it all down. However having an x86-64 would have confused customers in the middle. Think back then it was all about massive databases - that was where the big money was and x86 wasn't really setup for the top end load patterns of databases (or OLAP data lakes).
      • NetMageSCW 7mo ago
        Steve Jobs quote seems appropriate and yet still hard for companies to learn: "If you don't cannibalize yourself, someone else will"
        • twoodfin 7mo ago
          In the end, Intel did cannibalize themselves. It wasn’t too long after the Itanium launch that Intel was publicly presenting a roadmap that had Xeons as the appealing mass-market server product.
          • AdamN 7mo ago
            Yeah they actually survived quite well. Who knows how much they put into Itanium but in the end they did pull the plug and Xeons dominated the market for years. They even had a chance with mobile chips using ATOM but ARM was too compelling and I think Apple was sick of the Intel dependency so when there was an opportunity in the mobile space to not be so deeply tied to Intel they took it.
            • twoodfin 7mo ago
              I think the difference was that replacing Itaniums with Xeons on the roadmap didn't seriously hurt margins (probably helped!) The problem with mobile was that it fundamentally required low-margin products, and Intel never (or way too late) realized that was a kind of business they should want to be in.
      • 7mo ago
    • phire 7mo ago
      > It’s as if they actually bought into the RISC FUD from the 1990’s that x86 was unscalable, exactly when it was taking its biggest leaps. That's exactly what was happening. Though it helps to realise that this argument was taking place inside Intel around 1997. The Pentium II is only just hitting the market, it wasn't exactly obvious that x86 was right in the middle making its biggest leaps. RISC was absolutely dominating the server/workstation space, this was slightly before the rise of the cheap x86 server. Intel management was desperate to break into the server/workstation space, and they knew they needed a high end RISC cpu. It was kind of general knowledge in the computer space at the time that RISC was the future.
      • twoodfin 7mo ago
        I wonder what their engineers thought.
      • p_l 7mo ago
        Honestly what broke Itanium the most was the extreme market segmentation that made Itanium very expensive with no path to mass use. Resulting in claim like "it's pretty good DSP, but hilariously overpriced".
        • twoodfin 7mo ago
          Exactly! But this was not just obvious in retrospect, it was what Intel was saying to the market (& OEMs) at the time! The only way I can rationalize it is that Intel just "missed" that servers hooked up to networks running integer-heavy, branchy workloads were going to become a big deal. OK, few predicted the explosive growth of the WWW, but look around at the growth of workgroup computing in the early 1990's and this should have been obvious?
          • phire 7mo ago
            I'm not sure thats a fair description of server workloads. I'm also not sure it's fair to say Itanium was bad at integer-heavy, branchy workloads (at least not compared to Netburst) The issue is more that server workloads are very memory bound, and it turns out the large OoO windows do an exceptional job of hiding memory latency. I'm sure the teams actually building OoO processors knew this, but maybe it wasn't obvious outside them. Besides, Itanium was also designed to hide memory latency with its very flexible memory prefetch systems. The main difference between the two approaches is static scheduling vs dynamic scheduling. Itanium was the ultimate expression of the static scheduling approach. It required that mythical "smart enough compiler" to statically insert the correct prefetch instructions at the most optimal places. They had to strike a balance simultaneously wasting resources issuing unneeded prefetches and unable to issue enough prefetches because they were hidden behind branches. While the OoO x86 cores had extra runtime scheduling overhead, but could dynamically issue the loads when they were needed. An OoO core can see branches behind multiple speculative branches (dozens of speculative branches on modern cores). And a lot of people miss the fact than an OoO core can actually take the branch miss-predict penalty (multiple times) that are blocked behind a slow memory instruction that's going all the way to main memory. Sometimes the branch mispredict cycles are entirely hidden. In the 90s, static scheduling vs dynamic scheduling was very much an open question. It was not obvious just how much it would fall flat on its face (at least for high end CPUs).
    • p_l 7mo ago
      Just remembered that part of the story: Part of the effort to ditch x86 was to destroy competition that existed due to second sourcing agreements. After already trying and losing in court the case to prevent AMD and others from making compatible chips, Intel hoped to push IA-64 for the lucrative high performance markets it dominated in PCs, and prevent rise of compatible designs from other vendors.