Can OS X handle dual monitors?

[NewProduct]

Hi karohan,

I know exactly what you're talking about. It does occurs on almost every Mac laptop that I have used. It's even clearly evident when using the MBPs at the Apple store. I think it really comes down to power management, and how much is allocated to the GPU. When the power adapter is in, expose is always perfectly smooth on a single screen. When you are powering an external display, even more power is drawn. When you rapidly invoke expose several times, it seems to make the power management logic observe the increased processing demand and subsequently steps up yield. Also, if you have several apps open, with consistent CPU activity, you may ironically experience smoother expose because of this.


I think we also have very high standards on what is considered smooth. Interestingly a lot of people I speak with do not notice little things like this.

 

[karohan]

Why? Doesn't pointing the lens toward the screen and triggering Exposé suffice?

I don't know much about photography but is it possible that the video doesn't capture at a frame rate fast enough to show the difference in smoothness that I see in real life?

 

[karohan]

Hi karohan,

I know exactly what you're talking about. It does occurs on almost every Mac laptop that I have used. It's even clearly evident when using the MBPs at the Apple store. I think it really comes down to power management, and how much is allocated to the GPU. When the power adapter is in, expose is always perfectly smooth on a single screen. When you are powering an external display, even more power is drawn. When you rapidly invoke expose several times, it seems to make the power management logic observe the increased processing demand and subsequently steps up yield. Also, if you have several apps open, with consistent CPU activity, you may ironically experience smoother expose because of this.


I think we also have very high standards on what is considered smooth. Interestingly a lot of people I speak with do not notice little things like this.

Yeah, I agree with you. Sometimes having some more CPU intensive programs running will lead to smoother animations, but is there a way to get around this? It's really annoying...
I know people have tried playing around with the AppleGraphicsPowerManagement.kext but I don't know what to do with that exactly.
Though you think the power draw of the external monitor factors in? I figured it having its own power supply would deal with that.

 

[Hydramus]

I know what you are talking about. On my old MBP 15" (RIP), exposé would be smooth with no monitor attached, but I used to connect it up to a 30" ACD occasionally and exposé was noticeably more choppy to me. I believed this was a video/gpu issue where the little thing had to drive an extra 2560x1600 pixels.

 

[karohan]

I know what you are talking about. On my old MBP 15" (RIP), exposé would be smooth with no monitor attached, but I used to connect it up to a 30" ACD occasionally and exposé was noticeably more choppy to me. I believed this was a video/gpu issue where the little thing had to drive an extra 2560x1600 pixels.

So do you think this is a hardware issue or an OS X issue? It might be worth trying to install Windows in BootCamp to see if it suffers from the same issues? I don't really know an animation like Expose I could use on Windows though to compare with.

 

[The-Pro]

I hope i can help here.

I have a mid 2010 15" hi-es, i7 MBP aswell and i certainly know the issue. Thing is I only experienced this when i was hooked up to some crappy slow arse screen. It was horrible to use, anything was choppy, even just moving windows. This was when I first used a secondary screen with my MBP and i really freaked out, as i thought something was broken. When I bought myself a brand new screen though (a BenQ 24" LED widescreen display, absolutely gorgeous screen, great colours, great contrast 50,000,000:1, super slim slick design) now the choppyness is completely gone. so i think it depends on the screen you have, the latency of it perhaps, and the connection you use. I connected my MBP with the MDP to VGA adapter then the VGA cable to the screen and everything was seemed slower. Windows weren't as snappy when moving and games weren't smooth. When i connected with the MDP to DVI adapter then the DVI cable to the screen everything was smoother again. Games had more fps then with the VGA connection. And everything was even snappier when i used the dual link DVI adapter. So there is definitely a difference between the different adapter and/or the connection type.
And then again a quick screen solved my issues to the most part

hope this helps a little

 

[karohan]

Hmm thats interesting. I have a MDP to HDMI adapter, and to that I have an HDMI to DVI cable running to my external monitor. So I think that connection is fine, unless you think my adapter is malfunctioning.
I think my monitor is pretty high quality. It's a 24" Samsung 245BW. Of course its a TN panel, so when I say high quality I mean in comparison to other TN panels. It pales in comparison to other IPS screens of course.

 

[Transporteur]

So do you think this is a hardware issue or an OS X issue? It might be worth trying to install Windows in BootCamp to see if it suffers from the same issues? I don't really know an animation like Expose I could use on Windows though to compare with.

That's not an OS issue, rather than a result insufficient graphics power.

Since there is no such thing as Exposé on Windows (at least not without third party software), you can't really compare this.

Anyway, I know the "problem" as well (doesn't bother me, though). It really depends on your display size, the amount of windows and especially what is displays, plus your amount of VRAM.

My MBP had about 5.3MP connected with a 256MB graphics card and Exposé got choppy quite quickly, so with only a view windows.
My MacPro currently has about 8MP connected with 1GB VRAM and the amount of stuff that can be displayed before Exposé gets choppy is much higher.

 

[The-Pro]

Hmm thats interesting. I have a MDP to HDMI adapter, and to that I have an HDMI to DVI cable running to my external monitor. So I think that connection is fine, unless you think my adapter is malfunctioning.
I think my monitor is pretty high quality. It's a 24" Samsung 245BW. Of course its a TN panel, so when I say high quality I mean in comparison to other TN panels. It pales in comparison to other IPS screens of course.

hm ok, i had a MDP to HDMI adapter for my 55" Samsung TV. It never worked properly so i returned it. I read lots of reviews about MDP to HDMI adapters, lots of them weren't good at all It definitely possible your adapter has problems, (maybe read reviews about yours, check out what people say) i would more say its the HDMI to DVI cable. Never liked those cables, i never found one which worked well enough dunno

my advice, get a MDP to DVI adapter from Apple, and a DVI to DVI cable. Try that. Definitely works great with me

 

[karohan]

hm ok, i had a MDP to HDMI adapter for my 55" Samsung TV. It never worked properly so i returned it. I read lots of reviews about MDP to HDMI adapters, lots of them weren't good at all It definitely possible your adapter has problems, (maybe read reviews about yours, check out what people say) i would more say its the HDMI to DVI cable. Never liked those cables, i never found one which worked well enough dunno

my advice, get a MDP to DVI adapter from Apple, and a DVI to DVI cable. Try that. Definitely works great with me

Yeah, I got my adapter cheap. I had that cable originally because my old laptop only had an HDMI out. I will probably head to the Apple Store when I have time and try to compare with laptops at the store.

For some reason, I doubt things will be much better because like I said, disabling BeamSync cures all the choppiness. It's almost like OS X's vsync implementation sucks. I guess the only way to know for sure is to install Linux on this Mac and do a direct comparison but that's going to be a royal pain the butt.

 

[karohan]

That's not an OS issue, rather than a result insufficient graphics power.

Since there is no such thing as Exposé on Windows (at least not without third party software), you can't really compare this.

Anyway, I know the "problem" as well (doesn't bother me, though). It really depends on your display size, the amount of windows and especially what is displays, plus your amount of VRAM.

My MBP had about 5.3MP connected with a 256MB graphics card and Exposé got choppy quite quickly, so with only a view windows.
My MacPro currently has about 8MP connected with 1GB VRAM and the amount of stuff that can be displayed before Exposé gets choppy is much higher.

You would think that 512 mb of VRAM would be enough right? And the number of windows does not affect the choppiness. If I have 20 windows open or 2 windows open that choppiness is identical. In fact, the effect is probably more pronounced with fewer windows.

 

[Transporteur]

You would think that 512 mb of VRAM would be enough right? And the number of windows does not affect the choppiness. If I have 20 windows open or 2 windows open that choppiness is identical. In fact, the effect is probably more pronounced with fewer windows.

There must be something else wrong then. 2 Windows, even those who need relatively much processing power, such as videos or browser with youtube playing, should be smooth as butter on a 512MB graphics card, especially considering your total screen resolution of roughly 4MP.

 

[The-Pro]

Originally Posted by Transporteur
That's not an OS issue, rather than a result insufficient graphics power.

Since there is no such thing as Exposé on Windows (at least not without third party software), you can't really compare this.

Anyway, I know the "problem" as well (doesn't bother me, though). It really depends on your display size, the amount of windows and especially what is displays, plus your amount of VRAM.

My MBP had about 5.3MP connected with a 256MB graphics card and Exposé got choppy quite quickly, so with only a view windows.
My MacPro currently has about 8MP connected with 1GB VRAM and the amount of stuff that can be displayed before Exposé gets choppy is much higher.

You would think that 512 mb of VRAM would be enough right? And the number of windows does not affect the choppiness. If I have 20 windows open or 2 windows open that choppiness is identical. In fact, the effect is probably more pronounced with fewer windows.

What Transporteur said is correct, more VRAM will make it smoother. However any graphics card now a days has plenty of VRAM and power to drive the external screen, Especially the GT 330M which is a pretty good GPU. You dont need a 1Gb VRAM GPU, i know this cuz my old mac mini with the Intel GMA 950 (64mb VRAM, not dedicated, and like 2 shader cores, (the most crap GPU ever in a Mac to my opinion)) was able to power 24" monitor, at 1920x1200 pretty smoothly, expose was smooth too, i used that mac mini for 3 years before i got my i7 MacBook Pro. My MacBook Pro can power the 30" ACD without problems (using the dual link dvi adapter of course.)
the problems you are having are definitely not because of your MBP, i think its the HDMI adapter and/or the cable. Like i said using VGA makes everything a bit choppy, using DVI is silky smooth

 

[karohan]

Originally Posted by Transporteur
That's not an OS issue, rather than a result insufficient graphics power.

Since there is no such thing as Exposé on Windows (at least not without third party software), you can't really compare this.

Anyway, I know the "problem" as well (doesn't bother me, though). It really depends on your display size, the amount of windows and especially what is displays, plus your amount of VRAM.

My MBP had about 5.3MP connected with a 256MB graphics card and Exposé got choppy quite quickly, so with only a view windows.
My MacPro currently has about 8MP connected with 1GB VRAM and the amount of stuff that can be displayed before Exposé gets choppy is much higher.



What Transporteur said is correct, more VRAM will make it smoother. However any graphics card now a days has plenty of VRAM and power to drive the external screen, Especially the GT 330M which is a pretty good GPU. You dont need a 1Gb VRAM GPU, i know this cuz my old mac mini with the Intel GMA 950 (64mb VRAM, not dedicated, and like 2 shader cores, (the most crap GPU ever in a Mac to my opinion)) was able to power 24" monitor, at 1920x1200 pretty smoothly, expose was smooth too, i used that mac mini for 3 years before i got my i7 MacBook Pro. My MacBook Pro can power the 30" ACD without problems (using the dual link dvi adapter of course.)
the problems you are having are definitely not because of your MBP, i think its the HDMI adapter and/or the cable. Like i said using VGA makes everything a bit choppy, using DVI is silky smooth

Would you still blame my adapter/cable if I output just to the 24" external monitor and the animations were not choppy? If the adapter/cable was the issue, the animations should be choppy in this case too right?

 

[NewProduct]

Yeah, I got my adapter cheap. I had that cable originally because my old laptop only had an HDMI out. I will probably head to the Apple Store when I have time and try to compare with laptops at the store.

For some reason, I doubt things will be much better because like I said, disabling BeamSync cures all the choppiness. It's almost like OS X's vsync implementation sucks. I guess the only way to know for sure is to install Linux on this Mac and do a direct comparison but that's going to be a royal pain the butt.

Hi Karohan, you seem obsessed. Haha. It's an OS issue. You're hardware is definitely capable of pushing those pixels. Just take a look at all the high performance video games and apps that the MBP is perfectly capable of running. They are certainly more intensive then expose. Also, they make your fans run high and your temperatures go up!

The power management is controlled by the OS. The Mac OS X engineers must have made a design tradeoff so that quartz would not consume unreasonable amounts of power. Remember, battery life is a big selling point for Macs, sure Apple could have been more liberal with giving GPU resources to quartz, but remember that quartz is running all the time. Just unplug your power adapter and see what I mean, the choppiness will get even worse.

There are probably advanced ways you can configure the power management behavior to your liking. I'm not aware of how to do it. If it bothers you enough, it may be worth pursuing.

Also, of course make sure you have the "higher performance" graphics option set in your energy saving preferences.

Honestly, I do notice the choppiness and it would be nice if it were smoother, but it doesn't bother me.

 

[karohan]

Hi Karohan, you seem obsessed. Haha. It's an OS issue. You're hardware is definitely capable of pushing those pixels. Just take a look at all the high performance video games and apps that the MBP is perfectly capable of running. They are certainly more intensive then expose. Also, they make your fans run high and your temperatures go up!

The power management is controlled by the OS. The Mac OS X engineers must have made a design tradeoff so that quartz would not consume unreasonable amounts of power. Remember, battery life is a big selling point for Macs, sure Apple could have been more liberal with giving GPU resources to quartz, but remember that quartz is running all the time. Just unplug your power adapter and see what I mean, the choppiness will get even worse.

There are probably advanced ways you can configure the power management behavior to your liking. I'm not aware of how to do it. If it bothers you enough, it may be worth pursuing.

Honestly, I do notice the choppiness and it would be nice if it were smoother, but it doesn't bother me.

Yeah, I kind of am obsessed...and I wish it wouldn't bother me. But like I said I'm pretty OCD and something like this is making me regret going Mac. I don't mind choppiness when on battery because I'd rather save power then but what's the need for power saving when I'm on AC. I don't know sufficiently enough about editing .kexts and the like to work on this myself and I'm not really sure where to go to find out, so I figured someone on these forums would know.
Like if it wasn't for this choppiness, I would be so satisfied with my Mac. But right now, I feel like it's one of those routes I have to go because I need the battery life for college and it's not practical for me to spend hours getting hardware to work with Linux, but the way it's going now, I'm wasting hours trying to get things the way I like it in OS X too =/