There is no way the dreamcast is making the snes slow.

[guest123]

I have a question...how come you guys say that since the dreamcast is only 200 mhz, that's why it forces slow downs. I've already read all these stickies and did the tutorials very well after having to read all of them and google many things i needed. Also, Some (E) roms work better than others so there's defintly something wrong in your code. It is not the dreamcast but it's in the code. You can also think to yourself, why would a dreamcast play the games slow but my GBA with emulation game card can play them fine? Anyway, here is the details on the dreamcast...

Console
Lets take a look at the components inside a Dreamcast, and what their capabilities are:

* Processor: 64-bit Hitachi SH-4
o Processor clock speed: 200 MHz
o MIPS (Million Instructions Per Second): 360
o Bus speed: 800 MB per second
o Cache:
+ Instruction: 8 K
+ Data: 16 K
* Graphics: 128-bit 100 MHz NEC PowerVR 2DC
o Resolution: 640x480 or 320x240 interlaced
o Colors: 24-bit (16,777,216) maximum, as well as 16-bit (65,536) mode
o Polygon rendering: 3,000,000 polygons per second
o Geometry engine:
+ Alpha blending
+ Perspective correction
+ Gouraud shading
+ Anistropic, bilinear and trilinear mip mapping
+ Z-buffer
o Memory: 8 MB video RAM
* Audio: 45 MHz Yamaha Super Intelligent sound processor
o Channels: 64
o Sample rate: 44.1 KHz
o Special effects: reverb, delay and surround sound
o Memory: 2 MB RAM
* Memory: 16 MB
* Operating system: Windows CE-based or custom Sega OS
* Game medium: Proprietary GD-ROM (Gigabyte Disc)
o Transfer speed: 1800 kilobytes per second
o Storage capacity: 1.2 gigabytes
o Memory buffer: 128 K
* Modem: 56 kilobits per second (Kbps)

Like the N64 and the PlayStation, the CPU in the Dreamcast is a RISC processor. RISC stands for reduced instruction set computer, and means that the instructions and computations performed by the processor are simpler and fewer. Also, RISC chips are superscalar -- they can perform multiple instructions simultaneously. This combination of capabilities, performing more instructions simultaneously and completing each instruction faster because it is simpler, allows the CPU to perform better than many chips with a much faster clock speed.


Now after reading that, there is no way the dreamcast is slowing the roms down. Im not pressing the issue since you guys did a great job, just comibining my experience of game design for epic games and the cool new things you guys think of to help you out. Check the codes somewhere, I don't code for a living but I do models, so I can't help you guys. Hope to see this thing run games without them being so slow.

[Sir Savant]

Do you know what emulation is?

I believe what you are asking is similar to a question like "why isn't ps2 emulation perfect on my AMD64 4000+?". Regardless of whether or not a system is powerful enough to run a "subsystem", it still must interpret the commands. This is why we don't have 100% accuracy in emulation of nintendo every platform, because we still have to interpret mappers.

Also, Dreamsnes is a port (and so is Superfamicast, I believe). If the code was native to the Dreamcast, ie from scratch, then there would be no problem, or the problem would only exist for very few games.

The reason European games clock faster in some cases is that they have different refresh rates which decrease the amount of information the processor has to go through in order to produce the image you see on the television screen. Higher refresh rate = more processor time needed. (I think, don't quote me on that)

Anyways, I am sure there aer a few more reasons, and I am only thinking of these off of the top of my head. You probably won't get an answer here from the Dreamsnes team because they don't hang around here, but I am pretty sure you could email them. I did a while ago, and Marcus emailed me back. And as for SuperFamicast, the author is currently working on a Nintendo emulator which he hopes to be 100 percent accurate.

Someone more knowledgable is bound to answer this, and I only hope they don't take offense to this.

[semicolo]

Some roms run better because they must be less hardware intensive (snes speaking) so the emulator can work quicker on it, compare the graphics/complexity of those games you find better or worse.

Emulators for GBA seem to recompile the games, maybe one could try this on dreamcast to achieve better speed.

[Ex-Cyber]

Using a recompiler for SNES games would be a whole new venture. I don't even want to start to think about the timing issues it could raise.

[Cid Highwind]

Some roms run better because they must be less hardware intensive (snes speaking) so the emulator can work quicker on it, compare the graphics/complexity of those games you find better or worse.

Perhaps in some cases but not in all:

I consider Donkey Kong Country, Killer instinct and Chrono Trigger to be some of the better quality games in terms of sound and graphics, yet those games are near fullspeed, compare this with Uncharted Waters 2: New Horizons, and there's a major difference.

[Rand Linden]

The code could certainly be written to run full speed -- and faster -- but the work required is significant, and very few people have the time (or inclination) to invest in a project of that scale.

FYI, the graphics hardware built into the GBA is similar to that in the SNES -- and VERY unlike that in the Dreamcast.

What game design work did you do for Epic?

Rand.

[guest123]

I'm still in college at NC STATE and have a internship there to help create games, models, and explore. Nothing major you'll see on the shelf by me, just they have about 25 of us students who just watch and learn and show us the tricks of the trade. I have tried donkey kong, chrono trigger, and killer instint on my machine and they were not even near full speed. What programs do you use to create snes, i could ask a buddy of mine to give it a shot. knowing his skills man since he knows c++ by heart, he could probably tell you whats wrong in seconds.

[Ex-Cyber]

I consider Donkey Kong Country, Killer instinct and Chrono Trigger to be some of the better quality games in terms of sound and graphics, yet those games are near fullspeed

The hardware that those games pushed to look and sound so good mostly belongs to Nintendo's ROM manufacturing partners.

[Strapping Scherzo]

FYI, the graphics hardware built into the GBA is similar to that in the SNES -- and VERY unlike that in the Dreamcast.

Yeah, both have similar graphics modes and hardware accelerated sprites. No doubt, loopy, the author of SNES Advance, is a phenomenal programmer. But there's so much time saved when all you do is translate SNES backgrounds and sprites to GBA backgrounds and sprites. On DC, you either have to do a full software render of each frame, or... devise a rendering method to use the PVR to simulate a background and sprite behavior. But going this route will never be picture perfect. Just look at what BlackAura is doing with Genesis. He's admitted that, yes, using the PVR to render individual tiles is faster but will never be accurate.

For one thing, as far as I know you cannot do windowing on the DC like you can on SNES and GBA. Also, these system use tricks like changing sprite and tile values mid-render to accomplish cool effects; also not possible with DC hardware.

The DC hardware is specifically designed for 3D.

It's definitely possible to have fast SNES emualtion on the DC but, like Rand said, it requires more time and dedication than any coder here is willing and/or capable of providing.

[DcSteve]

It's definitely possible to have fast SNES emualtion on the DC but, like Rand said, it requires more time and dedication than any coder here is willing and/or capable of providing.

Does that apply for super-famicast

[Strapping Scherzo]

It's definitely possible to have fast SNES emualtion on the DC but, like Rand said, it requires more time and dedication than any coder here is willing and/or capable of providing.

Does that apply for super-famicast

Maybe. Maybe not. I'm not sure what my future holds in terms of the time I'm able to dedicate to my personal projects. My personal life is all jumbled right now. I would definitely enjoy the task though. I would learn a lot more about emulation because I would have to pretty much write an emu from scratch using technical docs and other emus as guides.

I had a couple conversations with loopy in the past. He wrote SNES Advance from scratch, in ARM asm, with the SNES technical documentation as his primary guide. If a similar thing was done on the DC in SH4 asm, there's really no reason why full speed emulation wouldn't be possible. But, keep in mind, snes9x is a very mature project. It would be hard enough to write an emu from scratch, but even harder to reach snes9x's accuracy and compatibility.