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Old 26 April 2015, 20:55   #64
Join Date: Jan 2010
Location: Kansas
Posts: 1,284
Originally Posted by Sandro View Post
the best way to know how fast is the 060 in mac emulators is disabling superscalar cache and make a sysinfo test


68060 /50 mhz all caches enabled = 38mips

68060 superscalar cache disabled = ??
It's not quite so simple as the 68060 branch cache may need to be disabled also (according to Jim). I would expect the 68060 to be severely handicapped with both superscalar and the branch cache disabled, perhaps even to the point of the 68040 outperforming at the same clock speed. In this configuration,

68060 has better instruction timings
68060 has twice the I and D caches
68040 has better branch performance
68040 has bigger instruction fetch (and in some cases better cache performance)

If we look at the results from the 68060 daughter board video I linked above, the CPU (integer) performance in the MacOS benchmark is close between the 68040 and 68060 on a per clock basis. The Mac 840AV with 68040@40MHz has a CPU rating of 158 which should be about 198 with a 68040@50MHz. A little less than half the 460 CPU score for the 68060 would outperform the 68040 by a relatively small amount. The better CPU score by the 68060 could be because of faster memory and cache performance of the overclocked 68060 and improved memory performance of the 68060 daughterboard. The 68060 does clearly win in performance vs the 68040 by out clocking the 68040. The FPU performance of the 68060 is substantially better than the 68040. It looks to me like it is at least 75% better at the same clock speed. I don't believe turning superscalar off (I believe FPU instructions still execute in parallel as with the 68040) or the branch cache off (I don't believe the FBcc instruction uses the branch cache) affects the FPU performance. Even a 68060@50MHz looks to me like a nice performance gain over a 68040@40MHz for MacOS emulation. Most 68060 processors will allow 60-65MHz for a substantial performance gain over a 68040@40MHz. The few blessed Amiga users with rev 6 68060 will have more than twice the performance of a 68040@40MHz for MacOS emulation.
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