Four cores or Eight?

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So what's the buzz about the new eight core Macs vs. the four core tower?

I've been trying to figure this out recently as I am about to buy myself a new tower.

No, working for Apple doesn't help as much as you might think. :biggrin:

Seems the price difference requires thinking about it. And wondering about the future.
 
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4. 8 would be overkill right now and from what I understand, this 8 core model was more of a "get it out now" with no changes to the motherboard or anything else.

If you want an 8 core, I would wait until the next revision when Apple will (hopefully) change more than the processors.

And seriously...you work for Apple yet you don't know? I know a guy who works on Soundtrack (I think..last time I talked to him he did) at Apple in CA and he knows a lot, though he won't tell me crap about it! :D
 
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The latest I heard is that with the current design of CS3 it does not run appreciably faster on the octo. I suppose we will start seeing some actual results in a few weeks?

And then the computer and software designers will have to get back to work?

:smile: :smile: :smile: :smile: :smile: :smile:
 
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4. 8 would be overkill right now and from what I understand, this 8 core model was more of a "get it out now" with no changes to the motherboard or anything else.

If you want an 8 core, I would wait until the next revision when Apple will (hopefully) change more than the processors.

And seriously...you work for Apple yet you don't know? I know a guy who works on Soundtrack (I think..last time I talked to him he did) at Apple in CA and he knows a lot, though he won't tell me crap about it! :D
It was not a get it out now release. It is a new motherboard so far as I know.

I of course am exposed to a lot of things being there, but the rubber hitting the road results with the 8 core isn't one of them. From what I've read the 8 is just a bit faster, but that could only mean we need to wait for the software to catch up.

Just trying to ponder if the $1100 or whatever it is is worth it.

And yes, memory and disk io always end up being the bottleneck. A truly fast multi processor computer would really be multiple computers, including io.

I'll probably end up with a quad and a pile of memory.
 
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http://www.barefeats.com/octopro3.html

This is a link to some real world tests done with the 4-core and 8-core
Bare Feats suggests that when you are running CPU hungry processes, like multiple simultaneous exports, then you will see dramatic effects.
They also claim that a reason why the 8-core is not blowing the 4-core out of the water is due to poor instructions of Tiger. Tiger wasn't built to optimize this many cores. When Tiger came out, dual core G5s were still fairly new. Alot has changed since Tiger's release as far as Apple's CPUs are concerned.
If I were buying a new Mac Pro, I would try as hard as possible to wait and buy one with Leopard pre-installed. Save a hundred-some bucks on the upgrade and perhaps there will be a price-drop or speed-bump between now and October.
You have to think, Apple engineers took into account the possibility of 8, 16, or 32 cores and obscene amounts of memory when they were desiging the archeticture of Leopard.

However I do agree, 1100 bucks can buy you a nice pile of RAM and Hard Drive space. I would have a hard time not buying a completely decked out 4-core instead of a more basic 8-core.
Good luck with your decision and be sure to let us know what you go with.
 
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So what's the buzz about the new eight core Macs vs. the four core tower?

I've been trying to figure this out recently as I am about to buy myself a new tower.

No, working for Apple doesn't help as much as you might think. :biggrin:

Seems the price difference requires thinking about it. And wondering about the future.
The answer is more complicated than your question. People buzz about perceived capabilities of "more is better", but that isn't always the case. You have to study the entire architecture to look for limiting factors and bottlenecks, and also operational characteristics.

For example, some folks think more RAM is better, but that's not true. I can get better results from 4 GB of match-paired RAM in a system than 5 or 6 GB of unmatched RAM.

Another consideration is the ability of the operating system to consume available features of the hardware. Apple typically does an excellent job here, as it controls both the platform and the equipment. Both Tiger and Leopard support 64 bit computing. However, you may see a performance degradation in Tiger if you run 32-bit and 64-bit applications simultaneously. Essentially, it has to change gears to accommodate the different addressing schemes of the applications. The result of these wasted processor cycles for internal switching is a delay in application performance. Leopard enhances 64-bit operation to address this problem.

Eight cores will process faster than four cores if you restrict your measurement to data already in the processor. Will you always run your CPUs at max capacity to extract optimum performance? Absolutely not. Each processor runs faster than the bus that feeds it. The advantage of multiple cores is to process disparate streams in serial rather than parallel operation.

So do you get enough of a performance boost to justify the price? That depends upon your application. I recommend looking at the Mac Pro Performance page on Apple's site. Note that only one case does the user receive a 3.1x performance benefit. Most of the increases are BELOW a doubling of speed from the baseline performance on older PowerPC architecture. The difference in performance between 4 core and 8 core (where noted) is about a .5 increase. Additional processors in a similarly equipped computer yield diminishing returns.

You'll get the best performance with 8 cores and max ram. If money is no object, go for it. If you're like the rest of us, you'll get more bang for your buck with 4 cores and more (matched) RAM.
 
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What it boils down to for me is more or less if the 8 core machine is faster per core than the 4 core is.

Reason being the 8 core has a newer motherboard design.

As to whether or not 8 cores can be used... of course. The first limitations of so many cores, though, are the same old bottlenecks of memory and disk io.

A lot of the software we write would already use them, but I can't say I know how well. There is already more than enough cpu to cover the disk and memory bandwidth.
 
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Just FYI, I debated long and hard about quad vs. 8 core when I updated my Mac a couple of weeks ago. I decided that at the moment there was little reason to go with the 3ghz 8 core machine, so I got a quad 2.6ghz with 8gig of RAM ($950 from OWC). I ended up saving enough cash on the deal to almost pay for a refirb MacBookPro 17" for the road.

Results? I shoot a 39mp digital back and have been thrilled with the performance of ACR 4 & PS 10 with these files, and that is with a bunch of other aps running at the same time (I hardly ever turn off a program once launched, and only shut down my machine once every couple of weeks, so I often have a dozen or more aps running at the same time, sometimes many more). I figure that by the time they widen all of the bottlenecks in the hardware it will be time for another upgrade, and then I will get the 8 core, or 16, or whatever they happen to have at the time.

For now I am a happy camper with my giant RAW files (of course, things really fly with the tiny D2X files as well)...
 
Joined
Apr 30, 2005
Messages
7,818
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Gilroy, California
Just FYI, I debated long and hard about quad vs. 8 core when I updated my Mac a couple of weeks ago. I decided that at the moment there was little reason to go with the 3ghz 8 core machine, so I got a quad 2.6ghz with 8gig of RAM ($950 from OWC). I ended up saving enough cash on the deal to almost pay for a refirb MacBookPro 17" for the road.

Results? I shoot a 39mp digital back and have been thrilled with the performance of ACR 4 & PS 10 with these files, and that is with a bunch of other aps running at the same time (I hardly ever turn off a program once launched, and only shut down my machine once every couple of weeks, so I often have a dozen or more aps running at the same time, sometimes many more). I figure that by the time they widen all of the bottlenecks in the hardware it will be time for another upgrade, and then I will get the 8 core, or 16, or whatever they happen to have at the time.

For now I am a happy camper with my giant RAW files (of course, things really fly with the tiny D2X files as well)...
Happy to hear that. Do you do any batch work?

I am currently crunching ~2200 images as a group, D2X NEFs, and finding just about everything takes too long on my dual Athlon PC. I thought it was fast machine until this.

Haven't paid up for CS3 yet. Been waiting til I decide on which platform my main machine will be.
 
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