Emulating at a higher clock speed

[someitalian123]

This is just a general question. I get full speed on shadow of the colossus with vu cycle stealing, but that only runs the game like it runs on the actual hardware. And everyone who plays the game knows that it was very choppy because it pushed the ps2 to its limits and the hardware could barely handle it. I was woundering it would be possible to emulate the ps2 at a higher clock rate to actually make it smoother than it is on the actual hardware. Kind of like this modded genesis/mega drive


http://www.youtube.com/watch?v=bPtmp-QC-gw

[Fayt756]

Couldn't you just use turbo or increase the frame limit?

[NarooN]

Yeah, increasing the framelimit is your best bet. You can do this with the .ini file.

[someitalian123]

yeah but doesn't increasing the framelimt speed up everything in the game, music, controller sensitivity, etc? I just wanted to make it smoother on parts that there would normally be slow down on the real hardware.

[natt]

A "reverse cycle hack" would be nice for some games that have slowdown in the emulated system (as opposed to slowdown emulating the system). Provided it didn't break anything, and actually helped the slowdown (would vary by title, presumably).

[miseru99]

Yeah, you can think of it as a "slowdown hack", couse it'll need lots of extra power of your hardware to add power to the emulated one, if you add that to begin with you would need to have a cpu able to run it without slider speedhacks, then well no casual top end hardware would be enough to smooth out SotC and that'll probably stay true for at least next 3-4 years, maybe longer seeing intel interest in mobile systems and closed architecture while amd flirting with the consoles and multi core systems which is nothing really nice for emulation.

Currently the only known way to play SotC without framedrops/choppy graphics is by owning PS3 and the PS3 version of this game.

[natt]

Yeah, you can think of it as a "slowdown hack", couse it'll need lots of extra power of your hardware to add power to the emulated one, if you add that to begin with you would need to have a cpu able to run it without slider speedhacks, then well no casual top end hardware would be enough to smooth out SotC and that'll probably stay true for at least next 3-4 years, maybe longer seeing intel interest in mobile systems and closed architecture while amd flirting with the consoles and multi core systems which is nothing really nice for emulation.

Currently the only known way to play SotC without framedrops/choppy graphics is by owning PS3 and the PS3 version of this game.

There are a lot of games that aren't SotC though, where an anti-slowdown hack could have potential use on many computers today.

[nosisab Ken Keleh]

There are a lot of games that aren't SotC though, where an anti-slowdown hack could have potential use on many computers today.

Not necessarily true sadly, you can count with desync issues the same way downclocking EE brings in many games. The advantage you could abuse VU cycle stealing with less fear of it stalling EE

Ah, and not forgetting to "convince" the game to increase the PS2 "FPS" rate also all the while keeping the needed 60Hz *NTSC Refresh rate for the TV (or bypass this step since there is no real need of it on PC... but is not really emulating PS2 anymore).

[Koji]

This is just a general question. I get full speed on shadow of the colossus with vu cycle stealing, but that only runs the game like it runs on the actual hardware. And everyone who plays the game knows that it was very choppy because it pushed the ps2 to its limits and the hardware could barely handle it. I was woundering it would be possible to emulate the ps2 at a higher clock rate to actually make it smoother than it is on the actual hardware. Kind of like this modded genesis/mega drive


http://www.youtube.com/watch?v=bPtmp-QC-gw

I think you misunderstand... VU cycle stealing will NOT give you results like a real PS2, it will give you WORSE results since it's akin to emulating an underclocked PS2.

The reason why VU cycle steal works so well for SotC is because it has an unlocked framerate. Because of that, an underclocked state allows for frame skipping (most PS2 games are hard coded to a frame rate and thus, if the system can't keep up causes slowdowns instead of frame skips).

Yes, SotC pushed the PS2, but if you can't emulate it without using EE and VU cycle hacks, you're not even getting on par performance.

[nosisab Ken Keleh]

I think you misunderstand... VU cycle stealing will NOT give you results like a real PS2, it will give you WORSE results since it's akin to emulating an underclocked PS2.

The reason why VU cycle steal works so well for SotC is because it has an unlocked framerate. Because of that, an underclocked state allows for frame skipping (most PS2 games are hard coded to a frame rate and thus, if the system can't keep up causes slowdowns instead of frame skips).

Yes, SotC pushed the PS2, but if you can't emulate it without using EE and VU cycle hacks, you're not even getting on par performance.

Not wanting to make a case, just to help understanding what VU cycle stealing does.

EE (the actual PS2 CPU) communicates with the VUs passing the bulk of floating point data (mainly the vectors for graphics processing). If the VU becomes idle it still has to wait for the new data batch from the EE which may be processing something else or even waiting response from some module till the time to return the attention to VU comes again.

VU cycle stealing changes this force interrupting EE to send it data wherever the VUs module needs them. This helps increasing FPS because graphics (vector processing) is normally more demanding than common integer and logic operations.

If not in excess (and this depends greatly on the game), those cycles stolen from EE don't prevent it from doing it's job in due time and little to no collateral effects come from VU cycle stealing hack. Yet, it may interrupt EE when shouldn't and so this may cause the general game flow to slowdown.

The "curious" thing is when that hack is too much the game's flow slows down. The PCSX2 FPS is still increased but the pace the action happens in each frame decreases and may be too much to be compensated by the FPS increase... when this happens the game becomes sluggish or/and laggy, a known phenomenon from excess VU cycle stealing and leads people to call it fake FPS (albeit the FPS is what is seen... just the pictures on each frame are being drawn slower than should).

So, VU cycle stealing is not about changing processor clocks... just does what it claims... steals cycles from EE that EE would be using to do something else so to force EE to send data for the VUs to crunch.

PS: What makes things more confuse is because that 60 FPS needed by PCSX2 are indeed an emulation of what would be the PS2 refresh rate, not directly related with the actual FPS on PS2 which can't be directly emulated as FPS but emulated as painting the actual picture to go with each PCSX2 frame. If the (motion in the) pictures are being painted too slowly on the frames, the FPS is high but the "images motion" is reduced.