6 worst Intel CPUs of all time

Intel has dished out some great CPUs as a part of both its mainstream as well as servers and workstation CPU line-ups over the last few years. Many of its mainstream consumer-grade CPUs have made it to our list of the best CPUs, with the likes of the Core i9-13900K even claiming the performance crown. This has been something of a comeback, as Intel has struggled technologically for years and, in 2022, finally felt the devastating financial effects of losing the edge in this space over its competitors. If you look back at Intel's history, you'll find tons of awful CPUs, and some of these will make you wonder how Intel only started running into financial issues recently.

Pentium 4

Intel's first great disaster

Back in the early 2000s, CPUs were far simpler than they are today, and most generation-to-generation improvements focused on clock speeds. In fact, CPUs were often named after their clock speeds and nothing else. When Intel was developing its next-generation Net Burst architecture, it seemed obvious to try and chase frequency, and the company had big plans, plans that went off the rails in an equally big way.

AMD was the first company to launch a 1GHz CPU with the Athlon 1000, which launched in March 2000, but Intel already had eyes on the 2GHz barrier. By the end of the year, it had launched its first Pentium 4 CPUs, the fastest of which got to 1.5GHz. In 2001, Intel was the first to 2GHz with its Pentium 4 chip, and a 3GHz model soon followed in 2002.

However, these frequencies came at a high price. Intel was forced to make Net Burst's pipeline extraordinarily long, which meant Pentium 4's instructions per clock (IPC) was well below even older Intel CPUs and what AMD had.

At first, Intel's plan was working well and Pentium 4 chips usually beat AMD's Athlons. Intel doubled down on its strategy by making Net Burst's pipeline even longer to hit higher clock speeds. A 4GHz Pentium 4 was to launch in 2005, followed by a 10GHz CPU in the near future. However, Intel's strategy was predicated on Dennard Scaling, which observed that frequency rose every generation without needing more power. By 2005, Intel had discovered Dennard Scaling no longer applied and that even 4GHz was hard to hit, leading to the cancelation of the 4GHz Pentium.

Intel's decision to reduce IPC to hit higher frequencies had disastrous consequences when those frequency gains dried up, and AMD took the lead in 2004. Intel ended up scrapping Net Burst, and designed a brand-new architecture that prioritized IPC over frequency gains like most modern CPUs.

Itanium

Intel's dreams of 64-bit evaporates

At the same time it was shipping Net Burst for desktops, Intel was also preparing an extremely ambitious plan for server CPUs. The x86 architecture, which was used for Intel's and AMD's CPUs, was limited to 32-bit computation, and for the emerging server market, Intel wanted to develop 64-bit processors with never-before-seen speeds. Intel discounted the idea of making a 64-bit version of x86 and partnered with HP to create the brand-new IA-64 architecture, which powered Itanium CPUs. The first Itanium chips were slated for a 1999 launch.

Itanium development was troubled, however. It was delayed until 2001 and the budget began to soar. When it did finally launch in 2001, its performance wasn't exactly competitive with other x86 CPUs, and only Itanium's ability to compute in 64-bit was a major selling point. But Itanium had a fundamental flaw: It couldn't run x86 software. All existing software needed to be rewritten for the IA-64 architecture, which was no small task.

If Itanium was impressive, it was simply for its refusal to die.

By 2003, AMD had finished its own 64-bit architecture called AMD64, which was a version of x86 with 64-bit support. Intel had previously decided against this strategy for various reasons, but in hindsight, it was clear that Itanium was a mistake since AMD's Opteron chips started snatching up market share. AMD64 also had the support of major software companies like Microsoft, which chose AMD64 as its 64-bit architecture of choice. In the end, AMD64 became so popular that Intel had to make its own AMD64 server chips called Xeon, and AMD64 became x86-64.

But here's the thing: Xeon did not replace Itanium. Intel and HP held out hope for years that this dual-architecture strategy would work out, even as companies like Dell and IBM stopped selling Itanium servers. Itanium stopped receiving yearly updates in the mid-2000s, with its last chip launching in 2017. It was finally discontinued in 2020, but not before sparking a massive lawsuit between Oracle and HP over support. If Itanium was impressive, it was simply because of its refusal to die.

Atom

As fast as an atom is large

Eventually, Intel cleaned up its act in the wake of the Pentium 4 and Itanium fiascos and returned to its traditional leadership position. By the late 2000s, Intel saw opportunities beyond desktops, laptops, and servers as devices like the iPod became extremely popular. But Intel had bigger aspirations than powering devices that could fit in your pocket; it wanted Intel CPUs in anything that could conceivably have a processor. Intel needed a chip that was small, efficient, and just fast enough to get by, so in 2008, the company launched Atom.

After taking a couple of years to iron out the kinks in the first Atom chips, Intel was ready to launch the Atom Z600, which was supposed to capture the smartphone market from Arm. It boasted performance far superior to anything Arm could offer and had the same power consumption. Anandtech was confident that the Z600 would change everything, saying, "the smartphone market in 5 years won't look like an extension of what we see today."

So, why doesn't your phone or toaster have an Atom CPU? Perhaps the most important reason is that x86 had never been used for smartphones or other devices, so the software would need to be rewritten. This was basically the same mistake Intel made with Itanium, and it killed its smartphone plans after six years. It probably also didn't help that Atom's only claim to fame was the netbook and "internet of things" devices.

But recently, Intel finally found a home for Atom in networking devices and its new hybrid CPUs like the 13900K, which has 16 E-cores descended from Atom CPUs. That doesn't change the fact that Atom was a disaster for over a decade, but at least it's useful for something now.

Core i7-7700K

Intel stops trying

Intel replaced Net Burst with Core, an architecture that found a balance between IPC and frequency, and it was immediately a hit. CPUs like the Core 2 Duo E6300 and Core 2 Quad Q6600 were much faster than AMD's disappointing successor to Athlon, Phenom. Intel's renewed onslaught in PC culminated with the showdown between its second-generation Sandy Bridge and AMD's FX Bulldozer CPUs in 2011, and Intel easily won. Intel was on the rise once again.

So how did Intel continue this momentum? By essentially launching the same CPU over and over again. That's not to say Intel wasn't making any progress at all; the company followed the "tick-tock" model, where Intel released a CPU each generation with a new manufacturing node (tick) and then a CPU with a new architecture (tock), repeating on and on. But these technological gains stopped translating into significant performance and value improvements like they had in the past, and it was because Intel didn't need to compete anymore.

The Core i7-7700K was perhaps the most infamous of these chips since it was literally a Core i7-6700K with a few extra MHz.

The end result was the seventh-generation Kaby Lake, which launched in 2017 and was neither a tick nor a tock but instead an "optimization," which is to say it was just last-generation CPUs with higher clock speeds. The Core i7-7700K was perhaps the most infamous of these chips since it was literally a Core i7-6700K with a few extra MHz. PCGamesN was particularly scathing in its review, saying that it was "a depressing slice of silicon."

This story has a happy ending because AMD finally made its comeback two months later by launching its Ryzen 1000 CPUs. These first-generation chips weren't winners in gaming, but they had amazing multi-core performance. The Ryzen 7 1700 thrashed the 7700K in basically any multi-core workload while costing about the same. The cherry on top was Intel's rush to get its eighth-generation CPUs out the door in the same year, which meant Kaby Lake didn't even make it a full year before it was made obsolete.

Core i3-8121U

We don't talk about 10nm

Although Intel was comfortable launching the same CPU twice in a row, Kaby Lake was never supposed to exist. Intel had always intended to stick to the tick-tock model and launch a 10nm CPU after the sixth generation, but development was going badly for the company's 10nm node. The plan for 10nm was extremely ambitious. It was supposed to have almost triple the density of 14nm, in addition to its higher efficiency. Intel should have known not to do this after it struggled to get its 14nm CPUs out on time, but it wanted technological superiority, so it went ahead.

The original target for 10nm was 2015, but since 14nm got delayed, 10nm did too. 2017 was the new launch date, but instead of 10nm CPUs, Intel launched its third and fourth 14nm CPUs. Finally, Intel launched a 10nm CPU based on the Cannon Lake architecture, the Core i3-8121U, in 2018. Unfortunately, it signaled not the start of a brand-new generation of CPUs using cutting-edge technology but the end of Intel's leadership.

The Core i3-8121U in 2018 signaled the end of Intel's leadership.

The 8121U was a terrible demonstration of 10nm and a terrible product in its own right. The 10nm node was so broken that Intel could only manufacture a tiny dual-core CPU with its integrated graphics intentionally disabled, presumably because they didn't work properly. Intel had bitten off more than it could chew with 10nm, and the consequences of the company's hubris would change its trajectory forever. With 10nm stuck in development hell, Intel could only rely on 14nm for anything that required a significant amount of performance.

As a side note, Intel lists all the CPUs it's launched in the past two decades on its website, and while the page for the 8121U still exists, the page for all 10nm Cannon Lake CPUs has been deleted, almost as if Intel is embarrassed.

Core i9-11900K

Failing to achieve liftoff

Intel pressed on with 14nm for years, and although each generation brought more cores than the last, the frequency gains from each refinement of 14nm were getting smaller, and adding more cores dramatically increased power consumption. By the time Intel launched its 10th-generation CPUs (the sixth in a row to use 14nm), AMD was already using TSMC's 7nm for its Ryzen 3000 CPUs. Intel's top-end Core i9-10900K couldn't beat AMD's Ryzen 9 3900X, which wasn't even the flagship, and didn't have PCIe 4.0 support, unlike AMD CPUs.

If 10nm wasn't an option, then the only thing to do was introduce a new architecture. Intel decided to backport its mobile-oriented Ice Lake chips to 14nm, bringing a much-needed 19% IPC increase. Perhaps Intel should have done this sooner instead of waiting for the seventh generation of 14nm CPUs but better late than never, right?

So 11th-generation Rocket Lake CPUs came with a brand-new architecture, but this came at a price. Firstly, backporting a CPU designed for a much denser node meant that the cores were massive on 14nm. Secondly, power consumption also goes up on older processes which makes adding more cores and increasing the clock speed more challenging. The end result was the "flagship" Core i9-11900K, which had a measly eight cores and a die size of 276mm2 — that's fewer cores than the 10900K while being larger.

The 11900K was doomed; it was technologically backwards and way too expensive at $539. It could barely match the $450 Ryzen 7 5800X (let alone the Ryzen 9 5900X and 5950X) and even lost to the 10900K in anything that wasn't extremely single-threaded. It's shocking Intel spent R&D on a brand-new CPU that couldn't even beat its predecessor convincingly. It's possible Rocket Lake was made for the sole purpose of getting PCIe 4.0 on an Intel desktop CPU. At least the rest of the Rocket Lake lineup was decent, since AMD stopped competing in the low-end and midrange.

A comeback, but at what cost?

With its 12th and 13th-generation CPUs, Intel has finally returned to performance leadership in PC, but the damage has already been done. 10nm was supposed to launch in 2015, but it only launched successfully in 2021 with Alder Lake and Ice Lake for servers. Seven full years of 14nm CPUs have reduced Intel to a mere shadow of its former self, something that hadn't happened when Intel screwed up with Pentium 4, Itanium, or Atom.

A common thread between all these failures is Intel's recklessness and lack of caution. Intel assumed Pentium 4 would be great and hit 10GHz, even 30GHz, without issue. Intel assumed Itanium would rule the data center and never seriously considered the possibility that nobody wanted to rewrite every single piece of x86 software. Intel assumed Atom would succeed simply because it was a great piece of hardware. Intel assumed its engineers could do anything and aimed for a ludicrous generational gain in 10nm.

On the other hand, it's also pretty ironic that two of Intel's most high-profile failures have allowed the company to make a comeback. Hybrid architecture CPUs like the 13900K are only possible because of Atom, and without E-cores, these CPUs would just be too large and power-hungry. 10nm also plays a massive role in Intel's comeback as it puts the company's chips at rough parity with those fabbed at TSMC. Hopefully, this disaster with 10nm has given Intel a newfound appreciation for how plans can go wrong.