Dolphin emulator is faster than PCSX2 why?????

[nosisab Ken Keleh]

Well i think this is a contradiction to some people but here it goes
This are the specs of Ps2
Sony PlayStation 2 Technical Specifications
CPU: 128 Bit "Emotion Engine" running at 300 MHz
System Memory: 32 MB Direct Rambus
Memory Bus Bandwidth: 3.2 GB per second
Co-Processor: FPU (Floating Point Multiply Accumulator x 1, Floating Point Divider x 1)
Vector Units: VU0 and VU1 (Floating Point Multiply Accumulator x 9,
Floating Point Divider x 1)
Floating Point Performance: 6.2 GFLOPS
3D CG Geometric Transformation: 66 million Polygons Per Second
Compressed Image Decoder: MPEG2
Graphics: "Graphics Synthesizer"
"Graphics Synthesizer" Clock Frequency: 150MHz
"Graphics Synthesizer" DRAM Bus bandwidth: 48 GB Per Second
"Graphics Synthesizer" DRAM Bus width: 2560 bits
"Graphics Synthesizer" Pixel Configuration: RGB:Alpha:Z Buffer (24:8:32)
"Graphics Synthesizer" Maximum Polygon Rate: 75 Million Polygons Per Second
Sound: "SPU2 + CPU"
Number of voices: ADPCM: 48 channel on SPU2 plus definable by software
Sampling Frequency: 44.1 KHz or 48 KHz (selectable)
I/O Processor CPU Core: Current PlayStation CPU
I/O Processor Clock Frequency: 33.8 MHz or 37.5 MHz (selectable)
I/O Processor Sub Bus: 32 Bit
I/O Processor Interface Types: IEEE1394, Universal Serial Bus (USB)
I/O Processor Communication: via PC-Card PCMCIA
Disc Media: DVD-ROM (CD-ROM compatible)

This are The Wii Specs :
Nintendo Wii Technical Specifications (#1 Japan)
CPU: PowerPC G5 Processor running at 2.7 GHz
RAM: 512 MB total (including 128MB for video and 64MB for sound)
Graphics: 600 MHz graphics chip
Storage: 15 Gigabyte hard drive built in
Media: Blue-laser disc technology
Connectivity: Wi-Fi for Internet connection
Nintendo Wii Technical Specifications (#2 America & Europe)
CPU: Dual IBM G5 PowerPC processors running at 1.8 GHz
RAM: 256 MB DDR main memory (including 64MB for sound, using a 7.1 sound system at 196 KHz)
VRAM: 128 MB GDDR3 video memory
Graphics: ATI graphics chip running at 500MHz (16 Pixel Pipe, 220 million transistors)
Media: Blue-laser disc technology
Connectivity: Wi-Fi for Internet connection

As you can see the differences are radical in both consoles but the problem is in the emulation the Ps2 works in interpreter mode
this means less speed hack and all the chips emulated even in games that dont use all the capabilities of the ps2 (allmost all the americans games) and the Ps2 emulator is becoming heavier, the Gamecube & Wii emulator works at Compiler level with more speed hacks and more features available if you want to prove if is fast the wii emulator just enable the options to make it look like the wii and your computer wouldnt be able to handle

PCSX2 0.9.4 to 0.96
Worked perfect with this hardware
Pentium D 2.88 Ghz Dual Core
600 Mb of Ram
Ati Radeon Xpress 200 Series 128 Mb

PCSX2 0.9.7 to Latest Version
I7 3.6 Ghz
1 to 2 Gb ram
Gpu the latest One

Dolphin requirement for Wii imitation look
AMD Black Edition 6 Cores Overclocked 4.5 Ghz
8 Gb Ram
GPU Amd HD 4 GB Crossfire configuration

As you can see the PCSX2 requires more CPU power than Gpu because it doesnt take advantage of the gpu but Dolphin takes advantage of Gpu and Ram this why is faster.
The emulation process in PCSX2 is based ¡n raw CPU power nothing else.
I was a friend of a Ps2 developer and i was having the Sony Ps2 SDK and it came with an emulator made by Sony but it was faster than Pcsx2 but unfortunate i returned the SDK the requirements for that emulator was the following
Intel or AMD Dual Core 2.0 Ghz (tested on intel celeron dual core 2 Ghz)
Ati Radeon 9250 256 Mb
256 Mb Ram
As you can see Sony made an emulator it runned perfectly all the games and those requirements are from my old computer and the emulator runned without lags it was a well optimized emulator i think the problem in the PCSX2 development is that the developers dont try to optimize the code to work faster or to try to use the GPU and Ram.
The prove of this would be the Ps2 emulator for Ps3 it work at software mode it doesnt use the Hardware of the Ps3.

The misunderstanding comes first from believing PCSX2 is interprets, it is recompiled (although there is a legacy interpreted mode).

Second, The Power PC has not many internal registers (although having 6 execution), the code coming from Wii is easier to translate for the x86 ISA and register usage can be almost directly assigned.

You are right about the GPU (in part), since Wii CPU does not have many float point registers the bulk of code is addressed to the GPU (like in PC), so the GPU has an easier translation also.

Now things are very different on PS2... there are dozens of such registers, a large part of float point processing (which include graphics and physics) is done at the VUs. Maybe the bulk of the VUs job could be pushed on the GPU but is not trivial task and I can't tell for sure how it would enhance things.

To make things harder, PS2 code is strongly pipelined, it has none those facilities coming from the branch prediction both the Broadway as x86 CPUs have, multithreading becomes a nightmare to accomplish. Notice the game's code itself plays a role here, not only the hardware.

Now the question, how to assign that much registers from PS2 to the fewer on x86? Answer, keeping the instructions referencing them in memory and waiting for a x86 register becoming free for assignment, sometimes even removing an already assigned and storing it on memory to give place to another register from another PS2 instruction. That is maybe one the most complex task of PCSX2 and one the most time demanding. It is the paradise of optimizations for PCSX2, and the hell also. If a game is "well behaving" the optimizations will do wonder, otherwise....

Let's stop here, even because I don't know all the complexity behind PCSX2, the little I know is enough to show me it is daunting.

Of course I don't mean Dolphin is easy or not complex, all that I mean is emulating Wii is easier on PC than PS2 is.

PS: Just for the records, although stated being 128 bits, PS2 hardware actually works with 32 bits registers ganged together, make the calculation.