Emulators, processors and clock speeds

[Kudistos Megistos]

Something I've noticed when lurking around emulator forums* and looking at system requirements is that a lot of people in the emulator community will recommend clock speeds, ask what the clock speed of people's processors are and give only their clock speed when asked a question, completely omitting the processor's architecture. Examples would be things such as "you'll need a 3.0GHz processor to run this" or "'how kind of processor are you using' '2.5GHz'". However, anyone who knows anything about processors knows that measuring the power of, say, an Athlon II and an i7 by looking only at their clock speeds is like measuring the speed of two runners by looking only at the number of strides they can take in a certain amount of time, completely ignoring the fact that one may take much longer strides than the other. I once read someone say that only idiots would buy a certain model of the i7 instead of a cheaper C2D with a slightly higher clock speed because he claimed the i7 was less powerful.

I was immediately inclined to call such people idiots, but the near ubiquity of this way of thinking and the fact that the only thing I know about console emulation is that it's a little odd makes me wonder, do emulators work in a very special way that makes the clock speed more important than the architecture, or are there just a lot of very "special" people out there imparting their wisdom?

*the pcsx2 forums are a notable exception to this

[nfitc1]

You have to consider that emulators actually mimic EVERY hardware function of the console they're trying to support. Everything has to be interpreted for one machine and translated to another on the fly. So while the PSX may have to separate processors for sound and video and the central bus directs them accordingly, an emulator has to mimic the bus, AND the sound processor, AND the video processor, AND the main processor while at the same time monitoring inputs. Actual hardware (which is more important in the case of video) is regulated via plugins, but they're still part of the emulator's thread.
So the main processor of your computer is doing the work of at least four processors. Video/sound has to processed before being sent on to your graphics card so it does relatively very little work. Add to that the on-the-fly translating of all the PSX machine code and you'll discover that CPU clock speed is by far the most important part. The more commands it can get through in a second the more likely it'll be to be able to process all 60 frames in a second.

[Kudistos Megistos]

So the main processor of your computer is doing the work of at least four processors.

I presume this is why machines that so the emulating often have to be orders of magnitude more powerful than the machine they are emulating.

Video/sound has to processed before being sent on to your graphics card so it does relatively very little work. Add to that the on-the-fly translating of all the PSX machine code and you'll discover that CPU clock speed is by far the most important part.

Really? So the megahertz myth isn't a myth when it comes to emulation? That actually surprises me

[Mako]

Is is my understanding that the emulator/s use a specific instruction set and some use advanced instruction set like, psx2 uses SSE3,SSE4 you would gain a great deal if the emulator used multitasking instructions, other than that though. I think you would benefit more from the higher clock speeds vs new processor on an old emulator here's why. If I upgrade my ram in my PSP unsolder and re-solder it the systems emulators wont use it however, if I upgrade the processor with the same instruction set just higher clock speed Bingo: Better performance. Get were I am going with this?. Old emulators like epsxe would benefit more from higher clock because they weren't programmed to take advantage of the new processors on the field today. At least that my take on it please feel free to correct me.

EDIT:Sorry for the grammar gotta work on that.

[Furzball]

I run a DS emulator so I could play my games in class with little chance of being caught. And yeah, MGHRTZ top out pretty quick depending on type of game. If it has 3d function (Ex animal crossing) it will slow down. If it is mostly 2d (harvest moon) it stays ok in speed.

[Bosola]

Something I've noticed when lurking around emulator forums* and looking at system requirements is that a lot of people in the emulator community will recommend clock speeds, ask what the clock speed of people's processors are and give only their clock speed when asked a question, completely omitting the processor's architecture. Examples would be things such as "you'll need a 3.0GHz processor to run this" or "'how kind of processor are you using' '2.5GHz'". However, anyone who knows anything about processors knows that measuring the power of, say, an Athlon II and an i7 by looking only at their clock speeds is like measuring the speed of two runners by looking only at the number of strides they can take in a certain amount of time, completely ignoring the fact that one may take much longer strides than the other. I once read someone say that only idiots would buy a certain model of the i7 instead of a cheaper C2D with a slightly higher clock speed because he claimed the i7 was less powerful.

I was immediately inclined to call such people idiots, but the near ubiquity of this way of thinking and the fact that the only thing I know about console emulation is that it's a little odd makes me wonder, do emulators work in a very special way that makes the clock speed more important than the architecture, or are there just a lot of very "special" people out there imparting their wisdom?

*the pcsx2 forums are a notable exception to this

There are very few emulators that can take advantage of multiple threads. It would, to be quite frank, be a complete ****ing nightmare to coordinate - it's difficult enough getting the different console 'components' to work in concord already, never mind when split over multiple threads. As such, emulators typically run on one core, using the same essential x_86 functions and opcodes. psx2 apparently uses SSE3, but it really is the exception.

NFITC1 is right when mentioning graphics: it's not as though PSX or whatever just parses PSone graphics instructions into OpenGL or whatever and passes to the graphics card; for various reasons, it's all done in software. Clock speed for the single core really is the bottleneck on emulator performance.

[Mako]

That is more or less what I was trying to get at. Also I believe dolphin/wii  emulator uses SSE3,SSE4 not sure though :/.

[nfitc1]

I presume this is why machines that so the emulating often have to be orders of magnitude more powerful than the machine they are emulating.

That's my understanding. That's why the PSX emulators' upper recommendations are well in to the GHz range even though the PSX CPU itself runs around 33.87 MHz.

Really? So the megahertz myth isn't a myth when it comes to emulation? That actually surprises me

Pretty much. When you try to do something in software what hardware does without any processing you'll take more time doing it (the mechanics behind that is insane, but true). The more instructions you can get through in a second the better. The MHz myth still holds for almost everything else that any computer does. It's always as fast as its slowest part (tends to be the bus or the RAM nowadays).

[Kudistos Megistos]

I presume this is why machines that so the emulating often have to be orders of magnitude more powerful than the machine they are emulating.

That's my understanding. That's why the PSX emulators' upper recommendations are well in to the GHz range even though the PSX CPU itself runs around 33.87 MHz.

And why my i5 750 gets 20fps on GTA despite the PS2 CPU being 300MHz...

(everything else I've played gets full fps easily, however)

It's always as fast as its slowest part (tends to be the bus or the RAM nowadays).

Apparently, the RAM is my fastest part

Also, fuck Microsoft for trying to push SSDs on us with their Windows Experience Index

[sl1982]

SSd's are worth it though.

[Bosola]

Hard-drive access is a real bottleneck. Lack of RAM caching is the next (not helped by those who believe pruning RAM usage below 99% somehow improves performance, when it does the very opposite).

[sl1982]

Yes, I actually wish windows 7 was a little more agressive with its caching. I have over 2gb free right now. It should fill that with something.

[nfitc1]

Apparently, the RAM is my fastest part

AARHGHEPABVVEE! I hate those "Experience Indexes" nonsense. They tell you nothing. That picture just means that for relative RAM speed, your RAM gets a rating of 7.5. It doesn't mean it's faster than your 7.3 processor. I'm not telling you because I think you don't know that, but that's the impression people can get from that. Picture this:

Kid1: Durpie-Durp! My RAhM es fastr then me's CPU! Iz gto a ratin' of 7 n m PCU goz a 6.8 lol! :DD
Kid2: So you have a dirt slow processor then? RAM doesn't go faster than 1.6 GHz nowadays.
Kid1: Huhm? Wat u say? Wht GHz?
Kid2: .......nevermind.

daro ne?

[Kudistos Megistos]

Hush, these things need to be explained in simple terms.

Or maybe Microsoft have made the grave mistake of not making something as simple as possible, but simpler. That would be bad.

In any case, they obviously serve a function for the less computer literate insofar as they let people know whether or not they need to pay the Geek Squad $300 to upgrade their RAM.

[nfitc1]

MS inteneded for that experience index garbage to help be decide whether or not their machines were capable of running things. As if the software would list a specific EI in order to run properly. To my knowledge, it never happened. All third-party developers (for games since that's all you need to know system specs for ) still list rarefied requirements on the side of the box.
Another failed attempt by MS to make things easy.

[Kudistos Megistos]

MS inteneded for that experience index garbage to help be decide whether or not their machines were capable of running things. As if the software would list a specific EI in order to run properly. To my knowledge, it never happened. All third-party developers (for games since that's all you need to know system specs for ) still list rarefied requirements on the side of the box.

It might actually be a bad thing that it failed, in some ways at least. If games had the list the necessary EI, would it force them to be honest about the system requirements for their games? We all know that if one's PC only meets the minimum specs, the game is unlikely to actually be playable.

[nfitc1]

I've seen Minimum, recommended, and even optimal now. But the problem with the EI is the video specs. Even if two cards generate the same EI, they may not be compatible with the software (eg, one uses OpenGL 2.0 and the other doesn't, but has more RAM). One may not be compatible with whatever that software needs.

[Kudistos Megistos]

I see.

I'm glad that the only games I play on my PC are FF7, Touhou and VNs; I don't have to deal with any of that