This makes literally no sense to me. So little sense that there was just no way I could finish out the evening without pulling out my PowerBook 180 to look at the memory usage on my 7.6.1 install.
I've made no specific optimization efforts except for disabling extensions and on boot-up, with Quicktime 4 installed, it's using 4 megs. (Specifically, 3861 kilobytes.)
I don't have VM on, but if I did, I wouldn't be at all surprised to see the system operate more efficiently.
This is my findings in the early 90s when PPC came out:
Typical 7.1+ System /PPC Code lay out in RAM
[**][Mac 68 Code][PPC code][68K Resources & Additional Code][PPC Resources & Additional Code]{variables and buffers in free RAM}
(Note: This is a generic program/OS map in RAM)
[**] is a 8 to 16byte test code for 68K CPU vs PPC CPU and sets the vectors to where the program starts (This aslo happens in Booting process of the machine.)
With this FAT System (both 68K & PPC code and resources) the program is only running what code it was told to go to by the test program. This only happens in FAT programs. If it was "Pure 68K" code, the PPC Processor would run it in emulatation mode. If it was "Pure PPC" code, the 68K would not be able to run it. Despite all that, the FAT program/OS is fragmented into 68K and PPC code segments; it would be more fragmented than stated in the above example. The points are this:
1) The mix of the two codes take up a lot of memory. That alone slows down the machine as it tries to adjust for space for variables and buffers needed by the program. Because of this alone, the system oftem crashes with "out of Space/RAM" errors on low memory systems like an LC.
2) In both the 68K and PowerPC processors (and in any processor in fact), when jumping more than a page of memory, 1 clock cycle is used up for each page jumped, not necessarily wasted but it is needed for the CPU to adjust registers. A page of memory can range from 256bytes to 1024 bytes or greater depending on the CPU.
Since PowerPC Code is interspaced with the 68K Code, when the CPU has to jump over the unused sections, it uses up clock cycles for each page jumped. This jumping of over unused sections slows down the program.
3) In eliminating or "stripping" either code, for that CPU the machine uses, two things happen:
a) Its memory footprint shrinks, giving more RAM for variables and buffers used by the program.
b ) Memory page jumping shrinks, freeing up clock cycles and making the processor run the code faster.
c) When stripping - what resources that are shared by both processors are kept.
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Note:
I have done this years ago so that my Macs can run faster and run more apps, which they do. But I do not swap hard drives from system to system because of this - example: I do not swap the hard drive from my PB190 (a 68K cpu) to my PB5300 (a PPC CPU) and visa-versa because the code on the drives have been stripped for those machines. The same with my Mac IIcx/ci, LC475, 800, 950, PowerBook Dous 210 - 280 (68K machines), PowerMac 7100, 7500, 6214, 8100, 9600, PowerBook Duo 2300, G3s (PPC machines), etc. The speed increases is significant to notice on these machines.
Programs like Photoshop the increase in speed is noticebable. On MS Word, it is not. Some games there is an improvement as well but not all. And when I was building servers in the 1990s, server apps also saw a benefit increased speed. All this includes shorter times watching that spinning watch when it occurs. In either case, the smaller/stripped program also loads faster into memory
I do have copies of the original FAT programs in case I have to reinstall and then strip them accorrdingly to those machines.
These are my findings, and one does not have to agee with them. What works or worked with me does not necessarily work for you. But for me this is why it works. I can not explain it simplier than that.
This is not for the faint of heart. If you think you are going to screw up during code stripping, then don't do it. If you think you can and would like to try, then do. But in either case, you should have a back up of the original program/OS in case something happens (like your hard drive failing). It is best to have such backups on multiple media like floppy disks, CDs and Zip/Jazz cartridges for example.