FS-UAE AfA OS extension: Mac performance vs OS 3.9

[Weaselrama]

Recently, I upgraded my FS-UAE OS 3.9 (Boing Bags 1-4) 68060/JIT enabled configuration with the AfA OS 4.8 extensions. Beyond the 4.1-like windows frames and gadgets it provides, it also gives OS3 anti-aliased TTF fonts which not only enhance the Workbench, but any application which supports font choices such as DOPUS 4 and MUI-based apps such as iBrowse. In fact, iBrowse HTML fonts settings can be set to use anti-aliased Truetype fonts as well. Right off the bat, this would suggest, to me anyway, an increase on FS-UAE CPU load and CPU temperature because of the added load on the Workbench running an additional software layer. My experience has been quite the opposite.

I have searched EAB and I don't see a thread which documents specifically why there is an (admittedly perceived) OS3 performance increase with the AfA OS extensions but there is another benefit from installing and using them: Better Mac performance and CPU cooling.

I keep my 2019 MBP 13" 2.4ghz elevated at an angle so that the airflow intake below the lid's hinge is better exposed. I run an external fan and use iStat's fan rules as well. Prior to installing the AfA OS and in a location where the ambient air temperature tends to be a bit warm, FS-UAE ran at appx. 109% of CPU with an average temperature (with external fan and fan rules) of 68-69C and a CPU temp of 88-89C. Without the external fan, the average was 70-71C and a CPU temp of anywhere between 90-96C. While the highest loads experienced were with Mp3s and video (via FFPlay) and best loads while gaming or sitting idle, 109% of CPU was the average experience.

After installing the AfA extensions and with other factors remaining the same (external fan, fan rules) I have enjoyed the following change: FS-UAE CPU 97-100%, an average temperature of 65-66C and a CPU temp of 85-88C. Again, my temperatures might be a bit unusual anyway because my office is on an upper floor with poor attic insulation and with heating in the cold season and warm weather in the hot season producing an average left/right airflow of around 35C.

I cannot account for the improved and cooler performance of the Mac and decreased FS-UAE load on the CPU using AfA OS. I admit that the apparent speed improvement on the Workbench may be perceptual on my part. I continue reading AfA/AROS documentation on the Internet looking for an answer but if anyone with AfA experience can point me in the right direction, I would appreciate it.

EDIT: Additionally, I've sent a request for info to Bernd Roesch, the AfA OS developer.

[Weaselrama]

I realize this is not FS-UAE specific, but rather, the apparent affect AfA OS has on FS-UAE performance. I wrote above that the apparent performance increase in OS3 is perceptual but it occurs to me that only a real-world performance benefit would translate to a real-world performance improvement in FS-UAE.