Performa 6116 & Sonnet Nubus G3 at 500mhz

#1 Thu, 22 Jan 2015 - 21:05 68kMLA

Hello,

i have the sonnet g3 at 500mhz installed in my performa 6116. I would like to ask what is the real speed that the performa can have with the card. At the apple system profile it says that the cpu is 240mhz but when i run the metronome for a test it says 480mhz.

Regards from Greece

Dimitris

#2 Thu, 22 Jan 2015 - 22:44 68kMLA

Try CPU Director or Norton's System Info for confirming CPU speed, benchmark using System Info or MacBench to confirm same speeds. Don't trust Apple System Profiler. Sonnet cards don't allow you to adjust multiplier/bus speeds so if it says 500Mhz you'd assume it is

#3 Fri, 23 Jan 2015 - 01:30 68kMLA

I think the speed is also different depending if you have a 60Mhz or 66Mhz CPU.

#4 Sun, 25 Jan 2015 - 15:40 68kMLA

It has to run at a multiple of the system bus - in a 60MHz machine, 8x the bus is 480MHz, in a 66MHz machine, 8x is 528Mhz.

Either way, you gotta admit that's a hell of an upgrade

#5 Tue, 27 Jan 2015 - 01:19 68kMLA

Bus speeds on those machines are 30MHz and 33Mhz. Hmmm. But the 500MHz G3s only supported multipliers to 10X, if I remember correctly.

The upgrade board must do something unnatural to the logic board bus speed, before feeding it to the CPU chip.

#6 Tue, 27 Jan 2015 - 03:00 68kMLA

they probably use PLL clock multiplier ICs on the upgrade board. since technically later 68K and PPC chips are asynchronous bus transfer, it doesnt matter how slow the bus is, you just have alot of wait states and poor performance.

#7 Wed, 28 Jan 2015 - 09:44 68kMLA

The truth is that the performa 6116 flys with the sonnet g3 installed. Some 68k games like Monkey Island, Gabriel Knight, Dark Forces (at high detail graphics) etc. are very slow without the sonnet card because of the 68k emulation. For me the best and most essential buy for the powermac 61xx series.

#8 Wed, 28 Jan 2015 - 11:58 68kMLA

trag said:
Bus speeds on those machines are 30MHz and 33Mhz

Right you are, my bad.

#9 Wed, 28 Jan 2015 - 18:31 68kMLA

techknight said:
they probably use PLL clock multiplier ICs on the upgrade board. since technically later 68K and PPC chips are asynchronous bus transfer, it doesnt matter how slow the bus is, you just have alot of wait states and poor performance.

I think that by the time of the 500 MHz G3 NuBus upgrade, the logic board bus speed did not affect the ultimate G3 CPU speed, or affected it very little. That's what I remember, in a not very reliable way. TK's information would tend to support that memory.