[S_Lanaway]

Greetings all,

I'm sure there are some of you out there in the 'technical know' that could shed some light on this.

It's my understanding that Quartz Extreme is meant to alleviate processor load and make everything feel a little more 'snappy'.

My laptop is the 1.33Mhz 17" running the latest Tiger. I find it a little sluggish, but it's ok (all things being relative).

At home I have an old AGP 400 Mhz G4, for which I swapped in a 1.2 Ghz G4 upgrade card from OWC.

Here's the thing. It feels speedier than my more modern laptop with the faster processor.

Why could that be?

We the other day I checked widgets on my old APG workhorse and discovered that when opening a widget, there is no 'ripple' effect. That must mean that Quartz Extreme is not able to run on that computer.

So what I'm asking is, for all it's eye candy splendour, does Quartx Extreme tax the CPU. Because my old AGP is way snappier in Tiger than my faster laptop and that's the only difference I can see.

Tell me if you think I'm out to lunch........

[Waragainstsleep]

Is the Sawtooth running Tiger too? Or still on Panther? I've noticed some odd discrepancies in speed between the two. On G4 systems, Tiger is almost twice as quick at running RC5-72 from distributed.net as Panther is on the same system (MDD single 1GHz and DA 733MHz). Both feel a little snappier for everything except printing too.

The dual 2.5GHz G5 in our showroom however is spinning beachball city since going from Panther to Tiger. Under Panther it was lightening.

If they are both running Panther, then I have no idea. Sorry.
Have you tried that hack to enable Quartz debug mode? Some people say it speeds their machines up a little.

[eddiecatflap]

maybe it's the faster hard disk ?

[Lateralus]

Your G4 has a faster HDD and much more processor cache.

[Big Mac]

And in any event, Quartz Extreme is certainly not the cause of your PowerBook's perceived sluggishness. Quartz Extreme has only ever shown performance benefits. Now Quartz 2D Extreme is a different story, but thus far it's been turned off in Tiger so that's not the issue, either.

[outsourced]

Sounds like you have two questions:

First, your PowerBook lacks any L3 cache. That's the main reason your PowerMac is faster, although it has a slower bus. Additionally, the faster hard drive in your PM is going to improve performance when accessing files or launching applications.

Second, Quartz Extreme is handled by the video card. It doesn't tax the CPU. That's the idea behind QE: Let the video card handle video -- What a concept!

With Tiger, we have Core Video. This also offloads certain video processes to the video card's CPU -- again, this relieves your main processor to do other business. You're not seeing the ripple effect because your video card doesn't support Core Video. It has nothing to do with processor speed.

Only certain video cards support Core Video in Tiger. There are several discussions in the MacNN Forums regarding this.

Hope this helps!

[S_Lanaway]

Both machines are running the current version of Tiger.

Specwise:

The OWC 1.2 Ghz G4 in an APG 400Mhz System:

OS: Latest Tiger
System Bus: 100 Mhz
Processor: OWC 1.2 Ghz w/ 2MB L3 cache
RAM: 1.2 Gigs
Video: RADEON 9600 PRO 4X AGP 64MB
HD: 7200 RPM 80 Gig

Powerbook:

OS: Latest Tiger
System Bus: 167 Mhz
Processor: 1.33 Ghz w/ 512 L2 cache
RAM: 1.2 Gigs
Video: stock 64MB
HD: 5400 RPM 80 Gig

So looking at these specs - where the Powerbook clearly has the edge in most areas - the souped up AGP G4 is so much faster because of the HD rotation speed (sorry, but the difference is drastic and has been notes in cases that don't involve reading from or writing to the HD). The 2MB L3 cache on the upgrade card is enough to overcome all the other technical inferiorities?? Quartz Extreme not being used is the only major difference I can think of.......

[S_Lanaway]

Hmm I'll have to do some research on Core Video. Thanks for the info.

But it does point to an underlying question..... when is the real benfit of Core Video on my PB if it slows that machine down so comparitively much??

I don't like that it gets its ass kicked by his much older sibling with a new, but still slower, brain.

[tooki]

Core Video is NOT the cause of the speed difference.

You are plain and simply seeing the difference between desktops and laptops.

tooki

[OogaBooga]

The processor cache is a major factor in the feeling of Snappiness™. More cache means faster performance, and the hard disk speed is equally as important. On the other hand, FSB makes a very small impact on perceived Snappiness™. So yes, this is why your desktop "feels" faster than your PowerBook.

[S_Lanaway]

Originally Posted by tooki

Core Video is NOT the cause of the speed difference.

You are plain and simply seeing the difference between desktops and laptops.

tooki

Tooki check out the specs.

I guess oogabooga has it figured. The cache and the hard drive.

Why didn't Apple give its top of the line pro portable a bigger cache? It is being beat by an OLD machine with a slower processor.....

[tooki]

I know the specs -- and additionally, I know how to interpret them. A 1.2GHz desktop will handily whip a 1.33GHz laptop.

It's always been like this -- portability requires sacrificing performance.

tooki

[S_Lanaway]

Originally Posted by tooki

I know the specs -- and additionally, I know how to interpret them. A 1.2GHz desktop will handily whip a 1.33GHz laptop.

It's always been like this -- portability requires sacrificing performance.

tooki

OK I get that but explain where the sacrifice is in the specs that accounts for the difference. Is it just the processor cache and the hard drive rotation speed?

If you match same generation desktop vs. portable I agree, it;s a historical and technological fact, there's always going to be a difference. But we're talking about a much older desktop with poorer specs.

[Todd Madson]

One reason there is a sacrifice is because if you had a portable with the same specs
of a desktop machine these days, you'd have a mighty weak battery life and a scalding
hot case. Hence the problems in developing a PowerMac G5. My G5 2.5 dual has of
late produced some really unreal temperatures in this hot weather.

[OogaBooga]

Originally Posted by Todd Madson

My G5 2.5 dual has of
late produced some really unreal temperatures in this hot weather.

Here in Austin it's been getting over 100º F every day consistently now. Luckily, it rained today. I usually keep the air conditioner set pretty low, but here in our apartment it still gets to about 80º in the afternoon. I got a box fan to take care of that problem, but it created a new problem -- that of noise.

Thankfully, my DP 2.0 has stayed relatively cool. Maybe it's partly because I keep the processor performance to "Reduced" at all times.

[tooki]

Originally Posted by S_Lanaway

OK I get that but explain where the sacrifice is in the specs that accounts for the difference. Is it just the processor cache and the hard drive rotation speed?.

Yes, I think those two things -- combined with the more aggressive power saving strategies on the laptop -- cause the difference.

Hard disk RPM makes a huge difference in many tasks. CPU cache wakes a huge difference in other tasks.

Also, the old desktop and the modern laptop have very similar architectures. It is not surprising that the laptop doesn't beat it.

tooki

[ginoledesma]

Well you could always run both of them through XBench to get numerical results. You'll see areas where your even your "aging" PM G4 will beat out your PB G4.

One note on the PowerBook, though, is Processor Performance set to "Highest" or "Automatic"? There is quite a difference when setting it to Highest all the time.

[Superchicken]

Faster HDD, potential difference between the amount of RAM, the L3 cache difference, take your pick. There's several reasons why a laptop will be slower than a desktop.