We’ve already covered the worst CPUs ever built, so it seemed time to flip around and talk about the best ones. The question, of course, is how do we define “best?”
In order to qualify for this article, a CPU needed to do more than just introduce significant new features or support a new instruction set. The Pentium Pro, for example, was a very important chip. It pioneered features still in use today and demonstrated that out-of-order execution and micro-op translation were viable techniques for high-end, next-generation processors. At the same time, however, the Pentium Pro had issues. It was slow when running 16-bit code and its FPU performance was only about half of comparable RISC cores at the time. The Pentium Pro was a very important CPU core, in other words — but it doesn’t meet our criteria when making a list of the best CPU cores ever invented.
To see which cores do measure up, check the slideshow below. We’ve taken a broad look at the industry over the past 40+ years, with mobile, server, and desktop CPUs all represented. Our selections were based on a variety of factors, including feature set, market impact, total strength of the product, and long-term performance.
Intel Celeron 300A
The Celeron 300A was one of the greatest enthusiast CPUs of all time. Overclockers quickly realized that the chip, which sold for $180, could regularly be overclocked to 450MHz. At that speed, it could match or outperform the Pentium II 450MHz, which sold for $655. Furthermore, when paired with the Abit BP6 dual-core motherboard, an enthusiast could run two CPU cores for less than the price of a single high-end Pentium II. Intel prevented this in later Celeron models and low bus speeds would handicap later chips, but the Celeron 300A was supremely well-positioned.
The MOS 6502 was critical to the home computer revolution that began in the mid-1970s. It powered the original NES, Commodore VIC-20, Atari 400 and 800, and Atari 2600, as well as two minor machines you may have heard of — the Apple I and Apple II. The famous Commodore 64 was powered by its direct descendent, the 6510. Far cheaper than competing CPUs, the MOS 6502 revolutionized affordability in the early computing era.
AMD Duron 600
AMD’s K7 architecture put the company on the map as a competitor with Intel, but it was the Duron 600, in 2000, that truly put the screws to Intel. The CPU’s large L1 (128K) compensated for a small 64K L2. If a pencil was used to unlock the CPU multiplier and lock the chip to a 1.85v vCore, the chip could boot at FSB speeds as high as 190MHz if high-speed SDRAM was used. An overclocked Duron 600 could regularly hit 950MHz-1GHz, annihilated the Celeron, and could even challenge the Pentium III at a fraction of its price.
The BAE RAD750, first built in 2001, is a radiation-hardened version of the PowerPC 750 CPU core. It’s on this list for the way it has enabled our exploration of the cosmos. The Mars Reconnaissance Orbiter, Lunar Reconnaissance Orbiter, the Kepler Space telescope, the Jupiter probe Juno, and the Mars probes Curiosity and InSight all use the RAD750. Plenty of chips make our lives easier on Earth, but only a handful of designs have touched the surface of other planets.
Intel Core 2 Quad Q6600
There were plenty of good Core 2 Duo CPUs, but Intel’s first mainstream quad-core was one of its longest-lived and most popular products. The Q6600 was in a relative sweet spot in terms of features and performance, with some professional VM capabilities Intel otherwise restricted and support for four cores at half the price of the Core 2 Extreme QX6700. Overclockers could push the chip from a base of 2.4GHz to well over 3GHz with the G0 stepping. Of all the C2D CPUs Intel launched, the Q6600 was the best overall part, hitting a near-perfect blend of price, performance, features, and overclocking capability.
Intel Core i7-2600K
Intel has launched a lot of good Core CPUs, from original Nehalem to the Core i9-9900K. The 2600K, however, arrived at a uniquely good time for the company. AMD’s Bulldozer had missed. The PC market had only barely begun to slump. The 2600K had great overclocking headroom and strong single-thread performance — there’s a reason it’s been a challenging CPU for Intel to convince consumers to move on from.
AMD Opteron 275
The AMD Opteron 275 and the Athlon 64 X2 4800+ were basically the same chip (the Opteron clocked slightly lower, at 2200MHz). The server variant gets the nod in our best-CPUs list for one huge reason: It delivered absolutely crushing quad-core performance on motherboards that also had AGP slots. Up until the advent of dual-core CPUs, there were no ATX or even EATX motherboards with four sockets and AGP. It wasn’t physically possible at reasonable price points. Quad-socket motherboards were very expensive, while dual-socket boards were much cheaper. The Opteron 275 made quad-core workstations with high-end graphics possible for the first time and offered dramatically better performance than Intel’s equivalent Xeons of the day.
The Cortex-A9 was the second CPU in ARM’s high-end Cortex family, but arguably the first mobile CPU to show what modern smartphones were truly capable of. The combination of higher IPC, dual cores, and higher frequencies relative to the Cortex-A8 made the A9 a popular chip for a number of high-end devices, including Apple’s iPhone 4S. When Intel wanted to bring its Medfield phones to market, the Cortex-A9 was the competitor product they had to position against. ARM continues to launch well-regarded mobile CPUs, but the Cortex-A9 deserves credit for launching the dawn of a new smartphone era in style.
Intel Banias (Pentium M)
Intel’s Banias (aka Pentium M, aka Centrino) solved a critical problem for Intel in the early 2000s: The P4 was emphatically not a mobile CPU. To solve this issue, Intel created a new CPU architecture based primarily on the P6 (Pentium 3) microarchitecture, with some strategic enhancements from Netburst’s DNA. The result was a power-efficient, fast CPU that Intel wrapped into a new push around mobile networking and branded Centrino. Centrino-branded laptops sold extremely well, and Banias became the first in a series of CPUs that would evolve into the Core 2 Duo, Nehalem, and eventually, Coffee Lake. Banias wins a nod for its impact on the notebook market, the overall success of the Centrino program, and its own excellent performance.
Qualcomm Snapdragon 800
Qualcomm’s Snapdragon 800 was the dominant player in overall mobile performance and powered a huge number of high-end handsets virtually from launch. If we stretch a bit to include the Snapdragon 805, devices of this era were pushing the boundaries of LTE and smartphone performance farther, with larger screens, higher resolutions, and rapidly improving camera technology. Networking performance on the Snapdragon 800 was far better than previous-generation LTE devices.
Apple has led the pack on single-threaded ARM CPU performance for years, but picking a single SoC was tricky. I’ve settled on the A9 for several reasons. First, it was objectively a great performer — the iPad Pro in 2015 used a derivative of this SoC, the A9X, to challenge Intel and Core M. That didn’t stop Apple from also scaling it into its diminutive iPhone SE, which showed the design’s flexibility. The iPhone 6S didn’t sell as well as the iPhone 6, but it was considerably better made than that device and did not suffer from the so-called “Touch Disease” that afflicted the iPhone 6 Plus.
The M1 is not listed here because, as impressive as it is, it’s also been in-market for about a week. No CPU can possibly demonstrate its own capabilities that quickly, so the M1 remains on our must-watch list for future inclusions.
Writing a “Best CPUs” list means that inevitably, a lot of really good CPUs are going to get left off the list. CPUs like the Intel 8086 or Motorola 68000 are often regular staples of articles like this, because of how they transformed the computing industry (launching the IBM PC in one case and launching the Macintosh as well as the Atari ST and Commodore Amiga in the other). We address many of Intel’s chips in more detail in our history of Intel products, parts one and two.
Honorable mentions for great chips that didn’t quite make our list would include the original Intel 4004, Pentium Pro, Pentium III, Intel’s Pentium 4 Northwood, AMD’s original K7, and CPUs like the Core i7-8700K. AMD’s recent Zen 3 parts are also potential contenders for this list, but I’m not comfortable naming such recent arrivals to the “Best ever,” list. Not quite yet. But the market impact of Ryzen can’t be denied — the third-generation Ryzen CPUs and Threadrippers have redefined performance in this market segment. Intel has slashed its prices across the Xeon and Cascade Lake families and dramatically improved its value proposition and Ryzen 5000 is building on what they started. All of these are factors that position Ryzen well in future comparisons, as far as inclusion on my personal “Best ever” list.
If I had to name a single “best ever” CPU, I’d go with the Opteron 275. Here’s my reasoning: Prior to the launch of dual-core CPUs, it wasn’t possible to have both a quad-socket motherboard and an AGP / PCIe slot. Quad-socket boards simply didn’t feature them. These boards were also quite expensive — thousands of dollars, IIRC, and while the initial Tyan boards for AMD were also pricey, at $500 – $800 (again IIRC), they were vastly less than a four-socket motherboard — and they shipped with features like PCIe. In a stroke, AMD had made far more computing horsepower available than ever before and done so while simultaneously adding graphics support. In terms of sheer impact on the market, and absolute reduction in cost, I have always felt the Opteron 275 deserved a special place in history.
Intel’s Desktop TDPs No Longer Useful to Predict CPU Power Consumption
Intel's higher-end desktop CPU TDPs no longer communicate anything useful about the CPUs power consumption under load.
VIA Technologies, Zhaoxin Strengthen x86 CPU Development Ties
VIA and Zhaoxin are deepening their strategic partnership with additional IP transfers, intended to accelerate long-term product development.
Nvidia Unveils ‘Grace’ Deep-Learning CPU for Supercomputing Applications
Nvidia is already capitalizing on its ARM acquisition with a massively powerful new CPU-plus-GPU combination that it claims will speed up the training of large machine-learning models by a factor of 10.
How L1 and L2 CPU Caches Work, and Why They’re an Essential Part of Modern Chips
Ever been curious how L1 and L2 cache work? We're glad you asked. Here, we deep dive into the structure and nature of one of computing's most fundamental designs and innovations.