Veteran Windows dev Dave W Plummer has run a simple performance test on all his computer lab systems and drawn up a fascinating comparison chart. Across his 25 computers, released between 1976 and 2023, he observed a huge 200,000X CPU performance delta. Moreover, it is admitted that the difference could have been much greater if the ancient Dhrystone benchmark performance code wasn’t resolutely single-threaded. The benchmark code also uses simple math, so the gains could be even more pronounced if it tested vectorized code.

I restore old computers, and am always curious how their classic performance compares to modern PCs. Are they a hundred times faster? A thousand? A million?Here are the stats. I wrote a Dhrystone test in K&R C that runs on everything I own, unmodified, from the PDP-11/34… pic.twitter.com/63ooTz2rkeNovember 10, 2025

If you’ve owned several generations of computers over the years, it can be interesting to step back and consider whether the newest is really that much faster than the oldest computer you owned. Veteran Windows dev Dave Plummer may have gone through a similar thought process recently, to drive him to create a code-portable Dhrystone benchmark and complete the tests. However, Plummer is blessed with an extensive computer lab featuring at least 25 computer systems spanning the 1976 vintage DEC PDP-11/34 to the Apple Mac Pro with M2 Ultra processor, released in 2023.

If you aren’t familiar with the DEC PDP-11/34, or the Apple machine, Plummer’s chart also features some of the most iconic systems / architectures in computer history. For example, the seasoned dev’s second-slowest machine is the Amiga 500 (score 1,000).

We also note the great progress from the first i486 machines through several generations of Pentium CPUs in Plummer’s benchmark. These figures show Intel’s solid progress from Dhrystones in the 30,000 to 2,500,000 score regions in roughly a decade, which included with the turbulent early Windows 9X era.

Other notable results / comparisons we would pick out are the scale of the uplift delivered in Apple’s transition from Motorola 680X0 chips to Power PC. Then there is the Raspberry Pi 4B standing proudly in the chart at nearly 10,000,000 points, and approx 4x faster than an iso-clocked P4.

Plummer also seems to have a big gap in his system collection after the P4 era. Where are all the lovely Athlons, Core-Duos, and Core iX series chips? However, atop of the seasoned dev’s chart we see two modern Goliaths, powerful examples of some of the best CPUs available in recent years: the Ryzen Threadripper PRO 7995WX with 96C/192T AMD Zen4 cores, and the aforementioned Mac Pro M2 Ultra with 24-cores of Apple Silicon.

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Dhrystones whystones?

In his Tweet thread, Plummer made it clear that all the charted systems ran a Dhrystone benchmark, that he wrote himself, naturally. It measures “Just raw compute on a single thread... not even taking into account multiple cores,” he explained.

If you are interested in this archaic CPU integer performance test, Plummer has made it available on GitHub. You have to grab the code and compile it for your platform. It is designed to be “specifically optimized for 2.9BSD on PDP-11 systems, while remaining compilable on modern systems for comparison.”

Running on systems newer than the 486 era, this benchmark code may fit entirely in a CPU’s cache, partly accounting for the significant uplifts seen in Plummer’s chart during this era change. Conversely, this code doesn’t use the advanced types of vectorized instructions that impart huge performance uplifts on modern systems, like AVX-512, so the overall benchmark gains could be even larger in some types of tests. That said, because Dhrystone fits entirely in cache, it also doesn’t test some of the primary bottlenecks in modern systems that limit performance, such as memory bandwidth or the performance of higher cache tiers.

Interestingly, as one X commenter notes, while the Amiga 500 is near the bottom of the chart, this 80s home computer with a humble 7.16 MHz 68000 CPU can still boot and open a perfectly functional word processor application faster than most modern systems today. Shove that in your Dhrystones chart…

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Mark Tyson is a news editor at Tom’s Hardware. He enjoys covering the full breadth of PC tech; from business and semiconductor design to products approaching the edge of reason.