recent ACube updates solve DVD playback problems on Sams

[Louis Dias]

Good news for Sam owners!

But isn't the Sam CPU too weak to play all DVD streams without frame skipping anyways?

I don't see why.  I believe I was watching DVDs on an Athlon 650Mhz way back in the day...  Clearly it seems like the PCI bus r/w speeds were the issue here.

Good news for all.

Perhaps new benchmarks will be posted when comparing speeds of various OS' and applications.

[Louis Dias]

Well, it would be because the Sam CPU is a very low performing and weak "G2" class CPU, never really intended for desktop or media usage.

Nice to see Acube releasing bug fixes though!

Hmmm I doubt a Trident video card with a mere 16MB of RAM had alot of acceleration going on.

Even the Gamebube (G3) @ 487MHz could do it. ;-)
http://en.wikipedia.org/wiki/Panasonic_Q

[Louis Dias]

Point is you are comparing apples and oranges, and maybe you are also putting too much attention to clock frequencies? And who was speaking about HW acceleration in video cards?

A G3 is usually faster than a "G2", for some application more than others. AFAIK a Pegasos 2 G3 is faster than any Sam. And a G4 is even faster, especially the newer ones, and especially for applications where Altivec make sense. As a result, MorphOS on a Mac Mini 1.42GHz plays x.264 720p streams better than a Sam plays DVD streams. A difference in work task that is a magnitude greater than the difference in clock frequency (of course other things affects the results as well, such as bus speed, etc).

Is a SAM considered a G2?  I don't think so.  It has something like 6 years of newer tech and faster(and much more) main memory than a Gamecube which was a G3. http://www.anandtech.com/show/858/2
The GC did have an incredibly fast memory interface for it's time.  Here ACUBE has fixed issues with moving memory hence the improved performance in DVD playback.  And besides my point is that SAM does have enough cpu performance to do it and not to compare x86 to PPC.

The memory interface was clearly the problem here.  SAM has a DDR(266) interface and my old PC was using SDR(100).  SAM should be able to outperform an Athlon 650 on large memory intensive tasks such as DVD playback ... but it wasn't.  I don't believe cpu performance has anything to do with it.  Even a P2 can decode Divx(@ SD resultions which is what resolution DVD is)...

Interesting:  I see here that A1 used PC-133 memory...
http://www.memoryx.net/amigaonexe.html

[Louis Dias]

Gekko has L2 cache and some SIMD instructions, both missing from the AMCC PPC440EP. While AMCC PPC440EP has some multimedia instructions they have little practical importance, while Gekko's SIMD is subset of altivec.

AMCC PPC440EP core is from 1999, same year as Gekko.

Yes, but I'll have to check with the Wii/GC community to see if they actually use that for their homebrew DVD player software, I'm sure the Panasonic Q was fully optimized.   Parralelism does help but if you can't feed the cpu fast enough (as was the case with SAM) then it's all for naught.  Improving the speed at which the cpu received data improved the performance here.

There were some performance benchmarks posted a while back regarding performance of the various PPC Amiga platforms and SAM(s) took a beating.  Perhaps now, those need to be re-run.  Many people have pointed out that MorphOS feels faster(than OS4) and this issue could be a major factor.  Now that it has been resolved, perhaps MorphOS team will be satisfied with the performance of SAM and issue a port.

[Louis Dias]

I'm sure it was also cheaper than the Sam, I know my PC was! One of the many strenghts with x86. But my Mac Mini was ahelluvalot cheaper than my PC, and it runs MorphOS! Not using it for 1080p movies though...

Anyway, I'm not the one using the "I was watching DVDs on an Athlon 650Mhz way back in the day ... Even the Gamebube (G3) @ 487MHz could do it ...  Even a P2 can decode ... so surely the Sam can do it as well" logic in this discussion. Apples and oranges!

http://amigaworld.net/modules/newbb/viewtopic.php?topic_id=32872&forum=33

The issues with DVD on the SAM remaining are AC3 decoding and the graphics driver is not optimized for DVD playback.  Onboard sound on PC's have been doing AC3 decoding for a long time now.  SAM has a dsp but I doubt it's being taken advantage of.  So it's not a lack of cpu power, it's a lack of proper drivers that take advantage of hardware.

I also rank an ATI 9600 > Gamecube Flipper gpu.  So again, I don't believe SAM is lacking in anything but proper drivers.

[Louis Dias]

Gekko has L2 cache and some SIMD instructions, both missing from the AMCC PPC440EP. While AMCC PPC440EP has some multimedia instructions they have little practical importance, while Gekko's SIMD is subset of altivec.

AMCC PPC440EP core is from 1999, same year as Gekko.

Yes, the Peg, A1 and wait for it: Gamecube all used the 750CXe.
But remember, my idea was crazy. ;-)
Wii is rumored to use 750CL.

(yes, I know some models had a cpu socket for upgrades)