Oh right. So I've just been looking up the PPC 740. It's a G3 with a PPC 603ev pinout no L2 cache bus and a higher potential clock rate. So, you replaced the old CPU (a 120MHz 603e)?
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Snial
Snial
@cheesestraws , oh so it can have a compatible pinout, and still not work because it’s too big/small. I guess so, the 603e/117 in a PB5300c is bigger than the 603e/117 in a PB1400. (Though I should check).
Phipli
@Snial - it doesn't look like they changed the CPU, it is visible in the second photo.
They probably have an L2 slot G3 upgrade. Sometimes the System struggles to tell between a 740 and a 750. But a 740 in place of a 603 isn't a huge speed boost. You get integer maths gains, but without the backside cache you just don't get the huge G3 gains clock for clock.
They probably have an L2 slot G3 upgrade. Sometimes the System struggles to tell between a 740 and a 750. But a 740 in place of a 603 isn't a huge speed boost. You get integer maths gains, but without the backside cache you just don't get the huge G3 gains clock for clock.
Snial
I briefly thought about it. For speeds in the 100MHz to 200MHz range I’d imagine that the 740’s missing L2 cache controller has less of an impact & the second ALU might bring it close to 604(e) performance?
Snial
I think I was imagining a 603e(v) Mac with an L2 cache, just not the backside one. e.g. you take a PM4400 with a 256kB cache and replace the 200MHz 603ev with a 200MHz 740 (or higher clock multiplier). Would it be faster than a 200MHz 8500? (Note, I don't plan to do this, I'm just pondering).