>>11878080>The DDR3 is used for the system's memory?That depends on the console being emulated, I know that is the case for PS1, Saturn and N64 and maybe the new GBA core that is in development.
>There are CD-based system cores that can make use of dual-SDRAM, what's the benefit there then?"Some games depend on the accuracy of the VDP1 timings. Some games depend on the accuracy of the VDP2 timings. Some games depend on the accuracy of the work ram (RAM-H,RAM-L) timings. Some games depend on the accuracy of the sound processor (SCSP) timings. Some games depend on the accuracy of the CD block timings. And some games depend on the accuracy of the combination of these components. The main sdram used by the VDP2 and the SCSP. The second sdram used only for RAM-H. The VDP1, CD, RAM-L, DRAM/backup cartridge (and RAM-H in single sdram build) use on-board ddr3 memory, which has latency. The ddr3 speed is not fast enough to provide all these blocks with the required access speeds. Therefore, due to these latencies, various problems can occur in games.
Only the RAM-H has been transferred to the second sdram, everything else remains in ddr3. That's why I say that it is not possible to provide 100% accuracy even in dual sdram build.
The FAST option makes half of Saturn's components (CPUs, SCU, ROM, RAM-L, CD block) inaccurate (faster than the original). It is needed to save a few cycles, which PARTIALLY compensate for ddr3 delays when accessing RAM-H in single sdram build.
About this issue.
The game intro code is programmed in such a way that it depends on the accuracy of RAM-H access speed. Here we need absolute accuracy of RAM-H reading by the CPU (that none of the emulators have). To provide such precision is possible only in a dual sdram build."
https://github.com/MiSTer-devel/Saturn_MiSTer/issues/251
>So the issue is that the DDR3 is also being used by the OS and other functions of the MiSTer and this can interrupt the N64's access to it?Correct.