Something is really wrong with the performance

About BasiliskII, a 68k Mac emulator for Windows, MacOSX, and Linux that can run System 7.x through MacOS 8.1.

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Sance231
Space Cadet
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Joined: Tue Dec 31, 2013 6:02 pm

Something is really wrong with the performance

Post by Sance231 »

There is one reason I use (or at least try to use) Basilisk II from time to time: I am a huge Prince of Persia fan and love the Mac versions of the first two games. My only problem is that they are not really working how they are supposed to. :(

I am using the latest Basilisk II (06-05-2013 if i remember correctly) on a Windows 7 64 bit computer and PoP1 runs very-very-very slow but at least the music plays correctly now. PoP2 is okay but the music plays too slow. The old versions has a whole different kind of problem: the music is all messed up in both games and PoP1 runs too fast.

I have an i7 2600, 3.4ghz cpu and a Geforce 560 GTX GPU with a fast HDD so I think that the problem is not on my end, also the old Basilisk could run PoP1 at full speed on my 7 year old laptop. How to configure the new Basilisk so the game runs faster?
Adam P
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Re: Something is really wrong with the performance

Post by Adam P »

Emulation for emulation.
Performance has been noted in the transition to 64-bit, where 32-bit software is treated as “legacy,” and some parts have to be emulated instead of run as-is (as your seven-year-old laptop does).

The older builds contain quite a number of assembly optimizations (which are processor-dependent—the i7 behaves differently than the Pentium 4), while the newer builds are managed pretty much strictly in C, even using 64-bit math (but with 32-bit glue, for compatibility).

It won’t be until modern-day 64-bit compilers actually work at optimizing code without breaking somewhere that a fast native build can be produced for Windows x64.

Geforce 560 GTX GPU, fast HDD:
Besides the “legacy” (where newer can actually mean slower), GPUs and HDDs of recent past are more than fast enough for high frame rates and fast loading speed. Everything in RAM, it’s really left up to the CPU. For the newer builds, there is bit more overhead, and compared to the older, priority settings for individual threads aren’t optional, as far as I can tell.

Slow music, PoP1 too fast:
You could try turning the music off for faster 2013 build performance with PoP1.

As far as accurate timing goes, Basilisk II/SheepShaver are not very good in the area of timing in general. They only do scheduled timing (time tasks, VBLs) at the standard 60.15Hz tick rate, no faster, no better latency besides use of the Microseconds trap. Anything can come out jerky or off, especially with sound channel timing (including QuickTime music). Only music rendered and mixed manually (e.g., Lemmings) can have consistency. But even then, the older builds can produce sync loss (e.g., QT movie AV sync loss).

Mini vMac does a better job at timing (a resolution as low as 1.04ms), however improperly interrupted at will (it shows, the clock losing time) and Mac II sound (ASC) doesn’t work.
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