Zilog Z80 vs. MOS 6502 vs. Intel 8080: Best?

Here’s everything about the Zilog Z80, MOS 6502, or Intel 8080 being the best:

In terms of raw performance, the Zilog Z80 was clearly the most powerful and capable processor of the three.

That said, the MOS 6502 was the most affordable, to the point where it changed the very nature of the industry.

Meanwhile, the Intel 8080 built a legacy that is still influencing computers today.

So if you want to learn all about the Zilog Z80, MOS 6502, Intel 8080 and see which one was the best, then this article is for you.

Let’s jump right into it!

What Is a Zilog Z80?

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This is a famous microprocessor that was developed in the 1970s.

To be more specific, it was among a few highly competitive 8-bit processors of the era (modern processors are 64-bit, and yes, higher numbers mean better processors), and this one was developed in 1975.

It ultimately launched in 1976 to great success.

It was designed to be compatible with the Intel 8080 (a processor we’ll discuss a bit later), and the Z80 represented a substantial upgrade to the 8080 systems of the day (there are more than a few versions of the 8080 that were released over the years).

The Z80 was specifically intended for embedded systems (meaning it was designed for systems with specific sets of operating software), but it was eventually used in common desktop computers and PCs throughout the late 70s and through the mid-80s.

It was also used in specialized systems, like synthesizers and arcade games.

Z80 Specs

Since we’re going to be comparing processors, we have to get into some of the specifications of the hardware.

I’ll explain what these things mean (in light terms) as we go.

For starters, the Z80 is a 4-micrometer chip.

Smaller is better because smaller chip sizes allow manufacturers to fit more computational power in the limited space available for any computer system.

Today, chips are measured in nanometers, meaning they are roughly a thousand times smaller, but in 1976, 4 micrometers was pushing the envelope.

Next up is pin set.

The Z80 was available with 40 and 44 pins.

Skipping a bunch of technical mumbo jumbo, 44-pin processors were way easier to work with at the time.

A very important specification is the clock speed.

This determines how many calculations a processor can make each second, so larger numbers are better.

The Z80 launched at 2.5 MHz (competitive for the time but not blowing other processors away).

Improvements to the system eventually pushed it up to 50 MHz, which was leaps and bounds ahead of other 70s processors.

Lastly, the Z80 contained 8,500 transistors.

The transistors are the tiny physical devices that actually do microprocessing, so more transistors are better.

At the risk of oversimplification, increasing the number of transistors increases the total amount of data a processor can handle at one time.

Again, providing modern context, a standard PC processor today contains multiple billions of transistors.

That’s a good list of specs, and since you have an idea of what each metric means, we can compare specs of the other processors pretty reliably.

What About the MOS 6502?

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Next up is the MOS 6502.

This was another highly competitive processor of the mid-70s.

This particular model was developed by MOS technology and introduced in 1975.

It was designed to be faster and less expensive than its predecessor, the Motorola 6800.

When it launched, it was the least expensive processor on the market by a substantial margin.

This really helped bring about the home computer market, making such devices considerably more affordable for home use.

It was used in many popular computers, including the Apple II and the Commodore 64.

It was also used in a lot of other computerized devices, like the NES and Atari 2600.

With the MOS 6502 pushing down the price of competent processors, it made many innovations through the late 70s and early 80s possible, many of which are reflected in its presence in home entertainment systems.

MOS 6502 Specifications

While the Z80 aimed to push the boundaries of microprocessing, the 6502 focused more on cost efficiency.

As such, you’ll see that all of the specs are lower in direct comparison, but the 6502 was still plenty capable for systems in the 70s and 80s.

For starters, it had 3,510 transistors.

That was possible because it was still a micrometer-scaled chip, but it couldn’t get transistor sizes quite to the minimum for the era.

The 6502 was another 8-bit processor, making it comparable to everything else of the age, and it also features the preferable 40-pin design.

In terms of raw calculation speeds, it was capable of 1 to 3 MHz performances.

How Did the Intel 8080 Compare?

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Last but not least of our processors today is the Intel 8080.

This was another highly competitive 8-bit processor, but this one predates the others by a year, having been launched in 1974.

This microprocessor is often given credit for really launching the microcomputer industry, and that’s because it was the first to champion the 40-pin design.

This and other choices made it much easier to interface than previous chips of the era, and everything that came after had to keep up or else get left behind.

The 8080 really set the stage for the other two processors, making clear certain design preferences that would dominate the industry for more than a decade.

Something really special about the 8080 is that it paved the way for x86 architecture.

This was a specific design philosophy that was adopted by Intel and wasn’t phased out until the 2010s.

In fact, some modern systems are still built on Intel’s x86 architecture.

Intel 8080 Specs

Though the 8080 was the first developed of the three processors we are discussing today, you’ll find that its performance sits right in the middle.

Compare that with modern development, and you’ll see that flagship processors see significant improvements every single year.

That’s because these three processors paved the way for the highly competitive personal computer market that we all know today.

With that in mind, let’s talk about transistors.

The 8080 housed 4,500 transistors, putting it right in the middle of the three for this metric.

It accomplished this level of transistor density on a six-micrometer design.

In terms of clock speed, it was capable of 2 to 3.125 MHz rates, making it fast for its day, but ultimately not as fast as advanced models of the Z80.

As I already mentioned, this processor used a 40-pin arrangement.

Which of the Zilog Z80, MOS 6502, or Intel 8080 Is the Best? (3 Categories)

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The thing about saying which of these three is the best is that they each played to different strengths.

One aimed to be the most powerful, another tried to be the most affordable, while another was built as a flagship that could sustain iterative design improvements for decades.

The truth is that each of the three was the best in its own regard, so let’s talk about the ways each one outshined the others.

#1 Raw Performance

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If you want to know which processor could do the most work the fastest, there’s a clear winner, and it’s the Zilog Z80.

It has many more transistors, which you now know means that it could handle much more simultaneous processing.

At the same time, it achieved the highest clock speeds, allowing for more calculations per second.

You put these together, and the Z80 blew away the other two in terms of pure performance.

If we compare some of the more advanced models, then the competition is even more lopsided.

The Z80 eventually reached clock speeds more than 10 times faster than the other two processors, all while holding more than twice as many transistors.

It’s a landslide.

But, as you know, raw performance is not the only thing that matters.

#2 Affordability

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And that brings us to the category of cost analysis.

For this category, the MOS 6502 is an uncontested winner.

It was in the same league as the Intell 8080 and the launch version of the Z80.

Despite that, it was considerably cheaper.

This low cost didn’t just make this processor better than the other two in a direct comparison.

It changed the legacy of this processor.

It was the technology that really made personal computers a popular thing by making them affordable for the first time in history.

The value of the cost-effectiveness of the MOS 6502 cannot be overstated.

#3 Legacy

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So far, we have discussed a processor that redefined performance metrics for a decade and the processor that made computers something people could afford in their own homes.

The 6502 also made gaming consoles possible by bringing down processor prices.

You might think that one of these two would have the most extensive legacy, but that’s not actually the case.

In terms of legacy, the Intel 8080 is the champion of the three, in no small part because it was the one made by Intel.

Out of these three companies, which ones have you heard of before?

Intel, right?

That’s because the other two fell into obscurity.

Meanwhile, Intel became the world’s undisputed leader in microprocessing development (a title that is finally being challenged by AMD) for decades.

That success was built on the design of the 8080.

The 8080 was designed as a flagship processor that Intel used to get into the industry of personal computers and microdevices.

For roughly two decades, Intel just worked on iterative improvements to this technology, and by the 90s, the company had emerged as an industry titan.

More than anything else, the x86 architecture that was pioneered for the 8080 became a staple in microprocessing.

As I said before, modern computers still use x86 architecture (although x64 is more prominent).

Nothing like that can be said about the other two processors.


  • Theresa McDonough

    Tech entrepreneur and founder of Tech Medic, who has become a prominent advocate for the Right to Repair movement. She has testified before the US Federal Trade Commission and been featured on CBS Sunday Morning, helping influence change within the tech industry.

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