It takes half an hour to boot into Windows 7 running on a 5 MHz CPU with 128MB of RAM

Shawn Knight

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TL;DR: The race to 1GHz was very much a real thing at the turn of the century. It was quite entertaining as well, coming down to a photo finish between AMD and Intel (the former took the win by mere days). Fast forward to today and you won't be able to find a new desktop CPU with a clock speed under 1.6GHz or so. But, you can underclock an existing chip to run much slower and that's exactly what NTDEV did in his latest video.

As part of a quest to the bottom, the YouTuber managed to successfully boot into Windows 7 Ultimate and even multitask with more than one program open at once. It's not nearly as glamorous as it sounds as Windows had to be run in Safe Mode and loads of system resources needed to be disabled.

The whole thing is run on a virtual machine that posts showing a Pentium-S clocked at 50MHz alongside 128MB of RAM. Once fully booted (a process that takes around 28 minutes), he is able to run programs like Notepad and another that displays the current clock speed of 5MHz. The YouTuber has even been able to run the system with just 36MB of RAM, but doing so requires using the page file.

If you were wondering, Microsoft recommends at least a 1GHz processor, 1GB of RAM and 16GB of storage to run Windows 7. NTDEV told Tom's Hardware that his install uses less than 1GB of space and required roughly 70MB of memory during the demonstration.

Predictably, the system is painfully slow but it isn't the slowest he has experienced. NTDEV previously managed to get Windows XP running at just 1MHz. That configuration took some three hours to boot, he said.

Next on the bucket list is figuring out how to get Windows 10 or Windows 11 to run on a chip clocked slower than 1GHz.

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Guys like this aren't just entertaining hobbyists flying the geek flag high. By doing the supposedly impossible they help expose a lot of the garbage that pollutes modern, commercialized operating systems.
Exactly.

And talking about that, I wonder how well would HaikuOS run under the same conditions?
 
:D I actually experienced something similar on a Surface Go thanks to a bug in Windows - if you plug it into the charger, sometimes it randomly throttles itself to the lowest clock speed, which is 400 MHz.

Threads about the problem exist since many years, but the bug is still present...
 
Looks like you need a minimum of 66Mhz to run Doom, although that's plenty of RAM. So, here's a machine that actually can't run Doom.
 
30 mins to boot into Windows 7 is not that bad. If you try booting into Windows 10 or 11 with a mechanical drive, it may take 15 mins before your system becomes responsive after booting into Windows even with a modern CPU. There's just too many background tasks with these new OS that the mechanical drive is struggling.
 
I find these too extreme and tortuous, I know it's for testing how low you can go, but I'd care to know for a Pentium 1 66mhz as the minimum.
 
5MHz CPU? Back in 1993 I bought i486dx2, 80MHz CPU. I guess I'd have to rip off a museum to get a 5MHz one.
Hmm, you have a point.

The original PC ran at 4,77 Mhz. That said, maybe 30 minutes is not that bad, considering how weak the 8088 was.

I know, this VM at 5Mhz is still faster than the 8088 because of the increased IPC.
 
"NTDEV previously managed to get Windows XP running at just 1MHz. That configuration took some three hours to boot, he said."
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I bet I could knock at least an hour or two off his best boot time

A 3 second native boot time from an SSD is average for my Nehalem dual-core

(It varies between 2.8 seconds and 3.4 seconds)
 
:D I actually experienced something similar on a Surface Go thanks to a bug in Windows - if you plug it into the charger, sometimes it randomly throttles itself to the lowest clock speed, which is 400 MHz.

Threads about the problem exist since many years, but the bug is still present...
Had that issue on my Acer Nitro 5 back when Ryzen laptop chips were new. BIOS update and Windows updates fixed it.
 
"Next on the bucket list is figuring out how to get Windows 10 or Windows 11 to run on a chip clocked slower than 1GHz."

All good things come to those who are willing to wait (and wait and wait and wait, etc...)! :laughing:
 
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