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Soup up your Tandy 3-in-1 with a V20

I’ve written before about my Tandy 1000EX with a Tandy 3-in-1 expansion to add memory, a serial port, and compact flash. And I’ve written before about the NEC V20 CPU. But did you know you can use them together to nearly double your compact flash storage’s throughput? Here’s how.

Hotrod your Tandy with a V20

Tandy 3 in 1 upgrade review

The Tandy 3in1 by Rob Krenicki is an essential upgrade for a Tandy 1000EX or 1000HX. You can improve its disk throughput if you have a V20 CPU by almost 100%.

The NEC V20 is a drop in replacement for the 8088-2 CPU that came from the factory. Exactly how much it improves performance depends on the apps you run and the benchmarks you believe. There are also rumors of compatibility issues, though finding someone who’s actually run into compatibility issues is hard. And finding someone who’s run into compatibility issues on a Tandy 1000 is even harder.

The addition of the Intel 80186 instruction set improves compatibility with some later programs, so it’s a tradeoff. I think you gain more than you lose with it.

If nothing else, a V20 runs cooler than a vintage 8088.

But the 186 instruction set gives you the opportunity to soup up the XT IDE BIOS in a big way. It roughly doubled the performance of my C drive, from 250 KB per second to 500 KB per second. And that is a difference you’ll notice.

Updating your BIOS for the V20

Rob Krenicki was kind enough to provide an upgraded 3-in-1 BIOS that supports the V20. Here’s a link to the two versions. Download the V20 version, then get the two files over to your Tandy. Run the xtidecfg utility to flash the BIOS. Here’s a walkthrough.

1. Load BIOS from file. Choose the file !3n1-v20.bin and press Enter when it prompts you.

2. Flash EPROM. Leave all the default settings as is, then select Start flashing.

3. Wait about a minute and a half, then press a key when it prompts you. It will reboot the system.

The boot sequence will all look the same, but the system will boot somewhat faster off the compact flash with the newer, better BIOS.

Checking your work

Run a benchmark and you’ll be able to confirm. Checkit rates the 3-in-1 running on the 8088 BIOS version as an entry level hard drive, regardless of which CPU you have. With a V20 and the BIOS update on board, it rates an intermediate performance hard drive.

I/O is one of the major bottlenecks in XT-class PCs, so this minor modification is very worthwhile if you have a 1000EX or HX and the Tandy 3-in-1. The system boots faster and programs load faster off the drive.

The only caveat is that if you ever decide to revert your 1000 to stock, you’ll need to load the 8088 BIOS back onto the card before you swap the CPU back.

The bottom line: This is supposed to be fun, and this simple upgrade makes the 3-in-1-equipped 1000EX or HX more enjoyable to use.

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1 thought on “Soup up your Tandy 3-in-1 with a V20”

  1. I have never actually lay a finger on a Tandy 1000. The more I read or absorb information about them, the more I think they are very interesting machines. Like a PCjr that was executed properly. It’s too bad that the Tandy line was discontinued and not something we see today on shelves along side Dell, HP and Lenovo.

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