Overclocking Performance

[phenomenalkai]

How much does overclocking actually affect the performance of Dolphin?
For example what would be the difference between a stock i5 4690k which runs up to 3.9 ghz and having it overclocked to 4.5 ghz.
I'm curious how much of a difference it actually makes.
thanks for reading.

[tuanming]

If you overclock 10% you will gain 10% performance.

[phenomenalkai]

(05-02-2015, 02:15 PM)tuanming Wrote: If you overclock 10% you will gain 10% performance.

Are there any visual differences in Dolphin though? for example the scan visor in the metroid games can be quite slow. Would OCing help something like that?

[MayImilae]

The scan visor operates at the speed the game sets. It's totally different from performance! If you are running the game at 45fps, the whole game and the visor will take 33% longer for everything, but to the game the visor will take the same amount of time.

Anyway, there are two factors that determine Dolphin's performance: IPC (instructions per clock) and the the clockspeed (4.5ghz in your example). IPC is why a 4690K @ 3.9ghz is faster than a 2500K at 3.9ghz - each single gigahertz does more work! But since you want to overclock, it's literally a linear speed improvement. A 4690K operating at 4.5ghz would be a 15% overclock, so everything will be running at 115% of what it did before. That means if you have a game that ran at 55fps at 3.9ghz, it would now run at 60fps (63 if you hold tab to turn off framelimiting). It wouldn't be enough to make a game that runs at 45fps to run at 60fps, as it would only go 52, so this is not infinite, but obviously it helps. Of course it should be mentioned that any game that is already running at 60fps will not see any improvements because of the framelimiter. Sure you can hold tab to turn the framelimiter off and it will go faster, but that's not very playable, and it doesn't really matter.

The only issue not addressed in this is the logistics of overclocking. All of this assumes that the 4690K can be stable at that 4.5ghz clockspeed (it might not), and that you are able to cool the 4690K so it can run constantly at that speed without throttling or shutting down. And of course you have to learn how to do it! But it's not hard, you just need to learn a lot of these things.

[phenomenalkai]

(05-02-2015, 05:44 PM)MaJoR Wrote: The scan visor operates at the speed the game sets. It's totally different from performance! If you are running the game at 45fps, the whole game and the visor will take 33% longer for everything, but to the game the visor will take the same amount of time.

Anyway, there are two factors that determine Dolphin's performance: IPC (instructions per clock) and the the clockspeed (4.5ghz in your example). IPC is why a 4690K @ 3.9ghz is faster than a 2500K at 3.9ghz - each single gigahertz does more work! But since you want to overclock, it's literally a linear speed improvement. A 4690K operating at 4.5ghz would be a 15% overclock, so everything will be running at 115% of what it did before. That means if you have a game that ran at 55fps at 3.9ghz, it would now run at 60fps (63 if you hold tab to turn off framelimiting). It wouldn't be enough to make a game that runs at 45fps to run at 60fps, as it would only go 52, so this is not infinite, but obviously it helps. Of course it should be mentioned that any game that is already running at 60fps will not see any improvements because of the framelimiter. Sure you can hold tab to turn the framelimiter off and it will go faster, but that's not very playable, and it doesn't really matter.

The only issue not addressed in this is the logistics of overclocking. All of this assumes that the 4690K can be stable at that 4.5ghz clockspeed (it might not), and that you are able to cool the 4690K so it can run constantly at that speed without throttling or shutting down. And of course you have to learn how to do it! But it's not hard, you just need to learn a lot of these things.

Good explanation! Thanks. How about the world map of Metroid Prime games? That thing will drop instantly when you press Z on the controller to activate it. I can easily go from 60 fps to like 28 fps. It's pretty fast when you haven't explored much but once you populate the map it can be a nuisance to use even though it's helpful to the game. Also does OCing have any performance impact on using V-Sync to prevent screen tearing or should I try Borderless window mode instead or neither?

[AnyOldName3]

If it halves the framerate, it might just be that that bit of the game is only supposed to run at 30 FPS (although it could well just be twice as demanding, too).

[MayImilae]

It isn't. Line drawing is fairly demanding right now, and that map screen uses a TON of lines! degasus is working on it.

phenomenalkai Wrote:Also does OCing have any performance impact on using V-Sync to prevent screen tearing or should I try Borderless window mode instead or neither?

V-Sync locks to specific framerates. For example, if you can't reach 60fps and instead are running 58fps, V-Sync will drop the framerate to 30fps to maintain the sync with the screen. Ouch! So if you are having trouble maintaining 60fps and are using v-sync, then overclocking could help push you over 60fps and back into the 60fps sync mode. Otherwise, overclocking has no effect.

And Exclusive Fullscreen is better than borderless, with lower latency and less overhead, so you should continue to use it if you can.