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PB 12 G4 1 GHz 32mb video running choppy with 26" external LCD


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PB 12 G4 1 GHz 32mb video running choppy with 26" external LCD
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eflutist
 
 
2005-03-17, 13:59

Hi - there are a number of posts regarding external lcd's. My question is whether or not I should upgrade to a new PB with a higher level processor and video card.

Currently I am running my 12" with only 32MB NVIDIA GeForce FX Go5200 graphics processor with AGP 4X support and 32MB of DDR SDRAM. I recently purchased an HP 26" LCD/HDTV with resolution of 1280x768. I have tried using my VGA and DVI adapters to connect to the LCD and the performance is REALLY taxing my video smoothness. Everything on my system related to the video tends to run choppy/sluggish while plugged in to the external LCD. Finder windows open in only 4 or so frames, my screensaver runs in noticeable frames (vs. the smooth quality it originally had), and my DVD player will just stop working or freeze/run choppy from time to time - and the only recourse is a restart. In general it seems that everything is just running slower/hesitating once hooked up to the LCD. Even after I disconnect the LCD. The performance is a little more dependable when I restart and don't connect to the LCD.

I went to the Apple store in Cambridge, MA, and inquired with the staff there (not the genius bar, just the sales staff) about what could be causing the slow down. They explained that a 26" LCD is a lot for my model PB to support (even though the tech specs say: Dual display and video mirroring: Simultaneously supports up to 1024 by 768 pixels on the built-in
display and up to 2048 by 1536 pixels on an external display, both at millions of colors).

Since I can't upgrade the video card - I'm wondering if I should sell this PB and get a new one with either a 64MB card, or even get the 15" with the 128MB option. Basically, the whole reason I bought the external LCD was to enjoy my mac performance on the big screen (especially DVD's etc.) and now what I seem to be getting is worse performance shown on a larger screen.

Recently, I've cleared all of the cache's with OnyX and have about 22 GB of free space on my HD. I also added the M-Audio Sonica Theater external USB soundcard for my logitech Z5500 surround sound system at the same time that I purchased the LCD.

If I was running a PC, I'd definitely run a defrag and all that, but I'm not sure mac requires a defrag - and don't want to install any of the 3rd party software to do so if it isn't necessary.

Any suggestions? I don't want to turn this into a financial/logistical fiasco if I don't have to - but I guess I opened that can of worms when I purchased the LCD. I'm ready to do what I must now, but I want to make sure it's the best step in the right direction!

Thanks for taking the time!

Adam

Power Book G4, 1 GHz PowerPC G4; Mac OS X (10.3.8); 768 MB DDR SDRAM
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cmeyer42
Member
 
Join Date: Jun 2005
 
2005-10-23, 17:10

Well, one thing you could try is to disconnect your external sound card and then try it. I've heard in my past life as a PC user that "funky" sound card drivers can cause major problems that seem like something else is wrong. So, disconnect and maybe even uninstall your sound card drivers (or disable them) and see if that works. (technically speaking, i think that your sound card is "hijacking" your data bus and it's not letting anything else use it like it's supposed to).
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torifile
Less than Stellar Member
 
Join Date: May 2004
Location: Durham, NC
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2005-10-23, 17:57

Quote:
Originally Posted by cmeyer42
Well, one thing you could try is to disconnect your external sound card and then try it. I've heard in my past life as a PC user that "funky" sound card drivers can cause major problems that seem like something else is wrong. So, disconnect and maybe even uninstall your sound card drivers (or disable them) and see if that works. (technically speaking, i think that your sound card is "hijacking" your data bus and it's not letting anything else use it like it's supposed to).
I think your advice isn't all that appropriate here. The Mac is very different from windows when it comes to drivers, etc.

How does it look when you're not using spanning? Just running the external display? While a 26" screen sounds like "a lot", it's actually not because the resolution isn't all that high. You should be able to do this without any problem. My wife's G3 iBook can run an external display at 1280 without problems.

Try checking to see what's occupying your processor. Go to "Applications/Utilities" and open Activity Viewer and see what's using up your CPU.

If it's not red and showing substantial musculature, you're wearing it wrong.
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scrouds
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Join Date: Mar 2005
Location: Orlando, FL
 
2005-10-23, 19:48

question for the tech heads here. Would running the Powerbook in closed lid mode free up the VRAM, so all 32MB can be used for the external display?
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MCQ
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Join Date: May 2004
Location: NY
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2005-10-23, 20:24

Something's up with your system. Hadn't run dual display on my rev. B PB in a while (same specs, except I have 1.25 GB memory), and I'm not seeing anything like what you're describing. Was playing one of the high-res h.264 encoded Systm episodes (http://www.systm.org) and had full playback (720x480, 30 fps) on the external display (a Dell 2005fpw, 1680x1050 resolution) while typing this response on the PB display.

The biggest difference I see with dual-display is a slight slowdown in Expose smoothness, but nothing for me to complain about. I was even running the Systm episode on the external and did Expose - no problems.

My only sugggestion is to ensure that your Energy settings are such that you have your processsor performance as "Highest".

Last edited by MCQ : 2005-10-23 at 20:31.
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chucker
 
Join Date: May 2004
Location: near Bremen, Germany
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2005-10-24, 01:16

Quote:
Originally Posted by eflutist
They explained that a 26" LCD is a lot for my model PB to support (even though the tech specs say: Dual display and video mirroring: Simultaneously supports up to 1024 by 768 pixels on the built-in
display and up to 2048 by 1536 pixels on an external display, both at millions of colors).
That's for analog use. Digitally, the limitation is more along the lines of 1680x1050 or some similar widescreen resolution, if not less.

Do you have Xcode Tools installed? If so, you can use Quartz Debug to see how many fps you have with normal use (just your internal screen), spanned use of both screens at a time and, thirdly, use of just the external display.

Quote:
Since I can't upgrade the video card - I'm wondering if I should sell this PB and get a new one with either a 64MB card, or even get the 15" with the 128MB option. Basically, the whole reason I bought the external LCD was to enjoy my mac performance on the big screen (especially DVD's etc.) and now what I seem to be getting is worse performance shown on a larger screen.
If that's important then yes, you should.

Quote:
Recently, I've cleared all of the cache's with OnyX and have about 22 GB of free space on my HD.
The rule of thumb on Mac OS X and most other modern OSs is to keep 30% minimum free on each partition. You seem to fulfill that, so that shouldn't cause a performance penalty.

Quote:
If I was running a PC, I'd definitely run a defrag and all that, but I'm not sure mac requires a defrag - and don't want to install any of the 3rd party software to do so if it isn't necessary.
A defrag won't do much good. An Apple file system engineer said that not only are noticeable performance improvements unlikely; there's also a risk of performance degradations if not (unlikely) downright damage to your hard drive.

Quote:
Any suggestions? I don't want to turn this into a financial/logistical fiasco if I don't have to - but I guess I opened that can of worms when I purchased the LCD. I'm ready to do what I must now, but I want to make sure it's the best step in the right direction!
If you want to drive two displays, each with independent contents (i.e. not mirrored), naturally each one of them takes up a slice of your VRAM. At 32 MB, that doesn't leave much room, especially with Quartz Extreme taking up a huge part in order to improve your screen performance.

What you're probably seeing is: once you set up your external screen to span, Quartz Extreme doesn't have enough VRAM left to turn its optimizations on in any feasible way. This leaves, technically, enough VRAM to drive both displays, but the accelerations, as said, are no longer in place.

Getting a replacement laptop with 64 MB of VRAM is definitely something to consider.

In fact, why not try it out? If you have an Apple Store nearby (assuming you live in a country that has them at all; haven't checked your profile), go to a store and kindly ask if you can try whether a current in-store PowerBook 12 is capable of driving your external display at a feasible performance. I hear they're usually quite happy to help out in such situations.

If you don't have a store, you may have a 14-day-return clause in your country's laws or your store's ToS -- in that case, just buy the new PowerBook, see if that fixes your problem (and then sell off your current one), otherwise, just keep the old one.

Again, try running Quartz Debug. If you can provide some numbers, that'll help me help you
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chucker
 
Join Date: May 2004
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2005-10-24, 01:17

Quote:
Originally Posted by scrouds
question for the tech heads here. Would running the Powerbook in closed lid mode free up the VRAM, so all 32MB can be used for the external display?
That depends on whether the chipset of the PowerBook 12-inch supports telling the GPU to really only communicate with the external display. Technically, the answer is "yes, it should".

I can't give you a precise answer since I don't have the actual display. It's definitely, however, something worth trying out for eflutist.

As I said in the previous post: since his display does work, in general, it's likely that there is in fact enough VRAM to drive both displays at a time, but not enough VRAM left to enable Quartz Extreme for both of them.
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Koodari
Veteran Member
 
Join Date: Jun 2004
 
2005-10-24, 16:58

I'm running the internal 1024x768 and external 1920x1200 off the iBook's 32MB Mobility Radeon 9200 and (of course) the external screen is VGA. No problems on desktop use, but it seems at least VLC and DVD Player can run out of memory and show weird effects if I try to go fullscreen with them - lately. I didn't see this before, nor do I see it all the time now.
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