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UMC UM82C481
A 386DX/486 motherboard acquired from an auction, with information, repairs, testing and benchmarks.
Initial Thoughts
The UMC UM82C481 seems to be a design from the middle of the 386 era; it has a compact chipset, but not quite the 1-chip solution of the very last boards, it has 8x 30pin SIMM sockets, sockets for up to 256KBytes of cache as well as the later, compact, PLCC version of the AMD 386DX-40. It would have been one of the better 386 designs that you could have bought at the time.
I got this board from a Russian-language auction site (https://streetmarket.ru/) in early February 2021 for a very reasonable amount of money. One of the reasons being that it had obvious damage…
Original Auction Images
Items to note:
- The battery has leaked, but appears to be relatively contained
Motherboard Data & Variants
A summary of the motherboard capabilities follows:
| Item | |
|---|---|
| Form Factor | |
| Chipset | |
| Dimensions | |
| Maximum RAM | |
| Cache | |
| FPU | |
| CPU Type | |
| CPU Speeds | |
| Expansion |
Motherboard jumper settings can be found in the following locations:
Configuration
0 Wait State & Further BIOS Optimisation
Math Co-Processor
Speed Testing & Tuning
Configuration 0
Results
| Test | Config 0 |
|---|---|
| Processor Speed | MHz |
| Wait states | 1 |
| Norton Sysinfo CPU | |
| Norton Sysinfo HDD | |
| Norton Sysinfo Overall | |
| CheckIt Dhrystones | |
| CheckIt Whetstones | |
| CheckIt Video chars/sec VGA 1 | |
| CheckIt Video chars/sec VGA 2 | |
| CheckIt HDD Transfer | |
| Landmark CPU | |
| Landmark FPU | |
| Landmark Video VGA 1 | |
| Landmark Video VGA 2 | |
| 3DBench VGA 1 | |
| 3DBench VGA 2 | |
| ATPerf RAM Read | |
| ATPerf RAM Write | |
| ATPerf ROM Read | |
| ATPerf Video Write VGA 1 | |
| ATPerf Video Write VGA 2 | |
| CompTest RAM thruput | |
| CompTest Effective WS | |
| CompTest MFLOPS | |
| CompTest Video BIOS VGA 1 | |
| CompTest Video BIOS VGA 2 | |
| CompTest Video Direct VGA 1 | |
| CompTest Video Direct VGA 2 | |
| CompTest Dhrystones |
Games Results
In addition, the following game benchmark results were recorded:
| Test | Config 0 |
|---|---|
| Wolfenstein 3D (FPS) | |
| F1GP Bench 1 (CPU %) |
Software Versions
- Norton Sysinfo 8.0
- CheckIt 2.1
- Landmark 6.00
- 3DBench 1.0
- ATPerf 2.00
- Comptest 260
Notes
Conclusion
(Go back to the 286 PC main page)