It definitely speeds up the data transfer rate and makes them a lot faster, a better experience. Sadly you're still limited to 1 processor core in a world where most computers that are in active use have at least have 2 processor cores.
For example I bought a "PiStorm" for my Amiga 1200 computer that uses the Raspberry Pi 4 Model B for processing power (RTG Graphics, RAM, and data storage too via the SD card) and it made my Amiga 1200 useable for daily driving but it's the 4 core Raspberry Pi 4 Model B doing all the heavy lifting, not the Amiga. All I use is the keyboard and the proprietary bespoke chips when playing games that "hit the hardware".
This is not an easy task. For those of you that don’t know the iBook G4’s logic board and hard drive are essential hermetically sealed in the plastic case AND a second layer of metal. I ruined my first iBook G4 when attempting this same upgrade as the ribbon cables that connect the power button and LEDs ripped in half from age (very brittle). I bought another used iBook G4. It still has the stock 60 GB hard disk and now the slot-loading “Super Drive” is dead so I will have to fix it eventually If I want to keep using it. I actually bought a used PowerPC G4 MacBook Pro to use and these are WAY easier to work on, just a few screws and you have access to everything.
I will note to anyone reading this the €79 Amiga-like Morph OS is really good experience on these 32-bit single core PowerPC Macs, very snappy. I also installed Debian 12 Trixie using the Sid branch on my iBook G4 via the USB-A port and using guides (and links to files to get WiFi working) on the Mac Rumours forum I got it working perfectly. Using the Window Maker Window Manager it’s snappy and you get NeXTStep?OPENSTEP experience.
I did the ssd upgrade to a G4 PowerBook* and it wasn't that dangerous. Nothing glued. Jut had some geek fun with 2 friends, all worrying about the tiny tiny screws and short and fragile cables.
If the iBooks are glued together, that's a totally different animal.
* unfortunately the GPU needs a reballing and without it the laptop only displays right in cold weather or for the first half an hour since power up :(
"The connectors at the ends of the cables are attached very firmly to the sockets on the logic board. Pulling directly on the cable will either separate the cable from its connector or the socket from the logic board."
For example I bought a "PiStorm" for my Amiga 1200 computer that uses the Raspberry Pi 4 Model B for processing power (RTG Graphics, RAM, and data storage too via the SD card) and it made my Amiga 1200 useable for daily driving but it's the 4 core Raspberry Pi 4 Model B doing all the heavy lifting, not the Amiga. All I use is the keyboard and the proprietary bespoke chips when playing games that "hit the hardware".