The Umax SuperMac C500 and C600 were the first “Power Macs” to have their CPU in a ZIF socket, making upgrades very easy. Having a C500/200 at work and finding an incredible garage sale special on upgrades from Small Dog Electronics, I decided to test the 240 MHz upgrade and the CacheDoubler.

Remember that benchmarks are arbitrary. They measure certain types of performance that may or may not reflect the way you work.

MacBench 5

The system was tested on 1999.12.14 using Mac OS 7.6.1 with a basic installation. Computer was attached to a 17″ color monitor and tested in 8-bit video mode at 640 x 480 resolution. The disk cache was set to 2 MB for all tests. The drive was not optimized before benchmarking.

Results are relative to a Power Mac G3/300 (beige), which scores 1000. The C500 would not run the graphics tests due to limited VRAM. Results marked “240×2” indicate use of the CacheDoubler.

Moving from a 200 MHz processor to 240 MHz, you would expect about 20% higher CPU and FPU figures, but MacBench 5 only reports a 7% improvement on the CPU score and 11% on floating point math. Perhaps the 40 MHz system bus is the bottleneck.

Replacing the standard 40 MHz 256 KB motherboard cache with the 80 MHz 1 MB CacheDoubler module makes a substantial difference on CPU score – it’s 58% higher than before using the same 240 MHz CPU, and an impressive 69% faster than the stock 200 MHz processor.

Floating point (FP) scores increase slightly, indicating the FP part of MacBench isn’t closely coupled to cache size.

An interesting improvement with CacheDoubler – the Western Digital Caviar 12100 hard drive scores 10% higher, while moving from 200 to 240 MHz had less than a 3% impact on drive performance.

Overall, the improvement is quite impressive, especially considering the blow-out pricing on these discontinued upgrades.

If you have a C500 or C600 with a slower processor (200 MHz or less) – or even a faster CPU without CacheDoubler – visit Small Dog Electronics to see if they have any left in stock. As I write this, the 240 MHz 603e processor sells for $29, the CacheDoubler for 200 or 240 MHz CPU for $9, and the CacheDoubler for the 280 MHz CPU for $29.

For information on installing the CacheDoubler in the C500, see our installation guide.

Keywords: #cachedoubler #supermacc500

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