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28 Articles

Benchmarking Chinese CPUs

November 26, 2025 by 25 Comments

When it comes to PCs, Westerners are most most familiar with x86/x64 processors from Intel and AMD, with Apple Silicon taking up a significant market share, too. However, in China, a relatively new CPU architecture is on the rise. A fabless semiconductor company called Loongson has been producing chips with its LoongArch architecture since 2021. These chips remain rare outside China, but some in the West have been benchmarking them.

[Daniel Lemire] has recently blogged about the performance of the Loongson 3A6000, which debuted in late 2023. The chip was put through a range of simple benchmarking tests, involving float processing and string transcoding operations. [Daniel] compared it to the Intel Xeon Gold 6338 from 2021, noting the Intel chip pretty much performed better across the board. No surprise given its extra clock rate. Meanwhile, the gang over at [Chips and Cheese] ran even more exhaustive tests on the same chip last year. The Loongson was put through typical tasks like  compressing archives and encoding video. The outlet came to the conclusion that the chip was a little weaker than older CPUs like AMD’s Zen 2 line and Intel’s 10th generation Core chips. It’s also limited as a four-core chip compared to modern Intel and AMD lines that often start at 6 cores as a minimum.

If you find yourself interested in Loongson’s product, don’t get too excited. They’re not exactly easy to lay your hands on outside of China, and even the company’s own website is difficult to access from beyond those shores. You might try reaching out to Loongson-oriented online communities if you seek such hardware.

Different CPU architectures have perhaps never been more relevant, particularly as we see the x86 stalwarts doing battle with the rise of desktop and laptop ARM processors. If you’ve found something interesting regarding another obscure kind of CPU, don’t hesitate to let the tipsline know!

Adding ISA Ports To Modern Motherboards

November 3, 2025 by 23 Comments

Modern motherboards don’t come with ISA slots, and almost everybody is fine with that. If you really want one, though, there are ways to get one. [TheRasteri] explains how in a forum post on the topic.

Believe it or not, some post-2010 PC hardware can still do ISA, it’s just that the slots aren’t broken out or populated on consumer hardware. However, if you know where to look, you can hack in an ISA hookup to get your old hardware going. [TheRasteri] achieves this on motherboards that have the LPC bus accessible, with the use of a custom PCB featuring the Fintek F85226 LPC-to-ISA bridge. This allows installing old ISA cards into a much more modern PC, with [TheRasteri] noting that DMA is fully functional with this setup—important for some applications. Testing thus far has involved a Socket 755 motherboard and a Socket 1155 motherboard, and [TheRasteri] believes this technique could work on newer hardware too as long as legacy BIOS or CSM is available.

It’s edge case stuff, as few of us are trying to run Hercules graphics cards on Windows 11 machines or anything like that. But if you’re a legacy hardware nut, and you want to see what can be done, you might like to check out [TheRasteri’s] work over on Github. Video after the break.

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A Walk Down PC Video Card Memory Lane

September 28, 2025 by 30 Comments

These days, video cards are virtually supercomputers. When they aren’t driving your screen, they are decoding video, crunching physics models, or processing large-language model algorithms. But it wasn’t always like that. The old video cards were downright simple. Once PCs gained more sophisticated buses, video cards got a little better. But hardware acceleration on an old-fashioned VGA card would be unworthy of the cheapest burner phone at the big box store. Not to mention, the card is probably twice the size of the phone. [Bits and Bolts] has a look at several old cards, including a PCI version of the Tseng ET4000, state-of-the-art of the late 1990s.

You might think that’s a misprint. Most of the older Tseng boards were ISA, but apparently, there were some with the PCI bus or the older VESA local bus. Acceleration here typically meant dedicated hardware for handling BitBlt and, perhaps, a hardware cursor.

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Computer Has One Instruction, Many Transistors

September 20, 2025 by 22 Comments

There’s always some debate around what style of architecture is best for certain computing applications, with some on the RISC side citing performance per watt and some on the CISC side citing performance per line of code. But when looking at instruction sets it’s actually possible to eliminate every instruction except one and still have a working, Turing-complete computer. This instruction is called subleq or “subtract and branch if less-than or equal to zero“. [Michael] has built a computer that does this out of discrete components from scratch.

We’ll save a lot of the details of the computer science for [Michael] or others to explain, but at its core this is a computer running with a 1 kHz clock with around 700 transistors total. Since the goal of a single-instruction computer like this is simplicity, the tradeoff is that many more instructions need to be executed for equivalent operations. For this computer it takes six clock cycles to execute one instruction, for a total of about 170 instructions per second. [Michael] also created an assembler for this computer, so with an LCD screen connected and mapped to memory he can write and execute a simple “hello world” program just like any other computer.

[Michael] does note that since he was building this from Logisim directly he doesn’t have a circuit schematic, but due to some intermittent wiring issues might have something in the future if he decides to make PCBs for this instead of using wire on a cardboard substrate. There’s plenty of other information on his GitHub page though. It’s a unique project that gets to the core of what’s truly needed for a working computer. There are a few programming languages out there that are built on a similar idea.

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VIC-20 Gets ISA Slot, Networking

August 26, 2025 by 22 Comments

There are few computing collapses more spectacular than the downfall of Commodore, but its rise as a home computer powerhouse in the early 80s was equally impressive. Driven initially by the VIC-20, this was the first home computer model to sell over a million units thanks to its low cost and accessibility for people outside of niche markets and hobbyist communities.

The VIC-20 would quickly be eclipsed by the much more famous Commodore 64, but for those still using these older machines there are a few tweaks to give it some extra functionality it was never originally designed for like this build which gives it an ISA bus.

To begin adapting the VIC-20 to the ISA standard, [Lee] built a fixed interrupt line handled with a simple transistor circuit. From there he started mapping memory and timing signals. The first attempt to find a portion of memory to use failed as it wasn’t as unused as he had thought, but eventually he settled on using the I/O area instead although still had to solve some problems with quirky ISA timing. There’s also a programmable logic chip which was needed to generate three additional signals for proper communication.

After solving some other issues around interrupts [Lee] was finally able to get the ISA bus working, specifically so he could add a 3Com networking card and get his VIC-20 on his LAN. Although the ISA bus has since gone out of fashion on modern computers, if you still have a computer with one (or build one onto your VIC-20), it is a surprisingly versatile expansion port.

Thanks to [Stephen] for the tip!

Back To The 90s On Real Hardware

August 22, 2025 by 8 Comments

As the march of time continues on, it becomes harder and harder to play older video games on hardware. Part of this is because the original hardware itself wears out, but another major factor is that modern operating systems, software, and even modern hardware don’t maintain support for older technology indefinitely. This is why emulation is so popular, but purists that need original hardware often have to go to extremes to scratch their retro gaming itch. This project from [Eivind], for example, is a completely new x86 PC designed for the DOS and early Windows 98 era.

The main problem with running older games on modern hardware is the lack of an ISA bus, which is where the sound cards on PCs from this era were placed. This build uses a Vortex86EX system-on-module, which has a processor running a 32-bit x86 instruction set. Not only does this mean that software built for DOS can run natively on this chip, but it also has this elusive ISA capability. The motherboard uses a Crystal CS4237B chip connected to this bus which perfectly replicates a SoundBlaster card from this era. There are also expansion ports to add other sound cards, including ones with Yamaha OPL chips.

Not only does this build provide a native hardware environment for DOS-era gaming, but it also adds a lot of ports missing from modern machines as well including a serial port. Not everything needs to be original hardware, though; a virtual floppy drive and microSD card reader make it easy to interface minimally with modern computers and transfer files easily. This isn’t the only way to game on new, native hardware, though. Others have done similar things with new computers built for legacy industrial applications as well.

Thanks to [Stephen] for the tip!

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Arduino VGA, The Old Fashioned Way

November 30, 2024 by 10 Comments

Making a microcontroller speak to a VGA monitor has been a consistent project in our sphere for years, doing the job for which an IBM PC of yore required a plug-in ISA card. Couldn’t a microcontroller talk to a VGA card too? Of course it can, and [0xmarcin] is here to show how it can be done with an Arduino Mega.

The project builds on the work of another similar one which couldn’t be made to work, and the Trident card used couldn’t be driven in 8-bit ISA mode. The web of PC backwards compatibility saves the day though, because many 16-bit ISA cards also supported the original 8-bit slots from the earliest PCs. The Arduino is fast enough to support the ISA bus speed, but the card also needs the PC’s clock line to operate, and it only supports three modes:  80 x 25, 16 colour text, 320 x 200, 256 colour graphics, and 640 x 480, 16 colour graphics.

Looking at this project, it serves as a reminder of the march of technology. Perhaps fifteen years or more ago we’d have been able to lay our hands on any number of ISA cards to try it for ourselves, but now eight years after we called the end of the standard, we’d be hard placed to find one even at our hackerspace. Perhaps your best bet if you want one is a piece of over-the-top emulation.