MAMEWorld Forums - EmuChat - Re: worth a look?: smaller-and-faster-data-compression-with -zstandard

> > > Space maybe but speed definitely matters for future chd compression/use. There's
> a
> > > reason the original PC based arcade games didn't have their data all zipped.
> >
> > that's not strictly true, plenty of games did have compressed data
> >
> > there are also logical reasons to do it, if you're dealing with streamed data then
> > you don't want i/o to become a bottleneck, so if you can stream compressed audio
> and
> > decompress it you're using less i/o time than streaming uncompressd audio. For
> > certain types of data it's also faster in general to load + decompress than load a
> > larger block of data (eg large amounts of text, if you load a dictionary first,
> then
> > only have to load lookup to words, it's a faster than reading raw data)
> >
> > also drive access speeds improve all the time, the majority of arcade systems that
> > are viable targets had slower drives anyway.
> >
> > yeah, it could be an issue, but it's definitely not a black/white thing.
> >
> > there are of course other interesting cases when it comes to i/o bandwidth, with
> GTA5
> > it's recommended you DON'T do a full HDD install on an Xbox 360, the logic behind
> > this seems to be that you end up i/o bound streaming everything from the HDD, but
> if
> > you stream some data from the DVD and other data from the HDD at the same time you
> > have more i/o bandwidth.
>
> By HDD, do you mean the mechanical ones only?
>
> How does that change with SSDs, then, if at all?

you can still end up limited by the speed of the drive controller etc.

for example putting an SSD in a PS3 seems to make absolutely no difference to performance even with games that are fully installed.

there are bottlenecks all over the place in systems.

I was reading a while back that one issue some devs have encountered in emulating video cards is that the ram on the video cards they're emulating is faster than the ram of the machines they're writing the emulator on, so even something as simple as a vram->vram copy done by the game will always be slower than 100% speed in the emulator because a simple memcpy isn't fast enough. Of course that only applies to the emulation of very recent systems.