Quad or dual core?

Mork

macrumors 6502
Original poster
Jan 9, 2009
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As a software developer, I'm thinking getting the 3.3 GHz dual core iMac would probably be a good decision. 8GB should rock!

I'm not sure that the quad-core, with slower processor cores (albeit four of them...) would make that much difference.

How do you determine the dual-vs-quad-core decision?

Thanks.

- M
 

thermodynamic

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May 3, 2009
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As a software developer, I'm thinking getting the 3.3 GHz dual core iMac would probably be a good decision. 8GB should rock!

I'm not sure that the quad-core, with slower processor cores (albeit four of them...) would make that much difference.

How do you determine the dual-vs-quad-core decision?

Thanks.

- M
How many tasks will you run?

And, yes, by and large a higher MHz rating will go farther than a higher number of cores at a slower MHz speed.

Then again, I went from a 2.93GHz w/4GB iMac (Mar 2009) to a 2.66GHz w/8GB Mac Pro (2009) and have only seen speed improvements. (the Xeon has more oompf than the previous-gen Intel used in the iMac), 8GB of course... ATi video... when all is balanced as a whole, I'd still do quad core...

Having said that, the iMac I had - dual core and all - was VERY POWERFUL (it certainly felt much faster than Vista Ultimate 64-bit on a Q9650-driven homebuild with 6GB RAM and a velociraptor HD, to say the least...)
 

thermodynamic

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If the apps you use utilize more than 2 cores, then get the quad.
Depends on the software, but more (including iPhone development) will make use of more than 2 cores.

Plus, even if one program uses only 2 cores, it can chug away and 2 cores remain to do something else. Again, keeping MHz speed in mind (eight 2.26 cores isn't as efficient as four 2.66 cores, but only by a few seconds on average for the apps that WON'T make use of multithreading)

http://www.macworld.com/article/139507/2009/03/macpro2009.html
 

zap2

macrumors 604
Mar 8, 2005
7,242
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Washington D.C
According to Gizmodo the i5/i7 up their clock speed when the extra cores aren't being used...so you might be better off with the Quad.(depending on you're usage.)

those Core i5/i7 chips are also clocked slower than the Core 2 Duo chips on the lower-end machines, but have the ability to run single core applications at a greater clock speed. Since all four cores won't be burning, the chip uses the spare electricity and the extra thermal overhead to dynamically and automatically overclock the core that is working: The i5 chip goes from 2.66GHz to 3.2GHz and the 2.8GHz i7 chip goes to 3.46GHz (with 4 cores that run hyperthreaded for up to 8 virtual cores.)
 

dwd3885

macrumors 68020
Dec 10, 2004
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According to Gizmodo the i5/i7 up their clock speed when the extra cores aren't being used...so you might be better off with the Quad.(depending on you're usage.)
you'll of course be better off with the i5. The question is whether it's worth the extra money. If you were set on 21.5", then it's an extra $500, if you want the 27 inch, then it's an extra $200.
 

irontony

macrumors member
Dec 10, 2005
82
0
New Zealand
If the machine is not going to be replaced for 3+ years then I would recommend the Quad - Get the best that you can afford.

I kicked myself for not getting the higher end models as now im stuck with it and iMac's cant upgrade their CPU/GPUS after production.

As others have stated, the turbo boost mode will be beneficial and software are heading towards multi-threads/cores. And even if the particular app isnt, its productive to still have free cores to do other tasks.

If however you upgrade regulary then a 3 or 3.3GHz would be perfectly wonderful
 

dwd3885

macrumors 68020
Dec 10, 2004
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If however you upgrade regulary then a 3 or 3.3GHz would be perfectly wonderful
exactly. My thoughts are by the time USB 3, Lightpeak and bluray come to the Mac (if they ever do), it'll be time for an upgrade and that's the perfect time to get a quad, 6 or 8-core cpu.
 

Mork

macrumors 6502
Original poster
Jan 9, 2009
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Depends on the software, but more (including iPhone development) will make use of more than 2 cores.

Plus, even if one program uses only 2 cores, it can chug away and 2 cores remain to do something else. Again, keeping MHz speed in mind (eight 2.26 cores isn't as efficient as four 2.66 cores, but only by a few seconds on average for the apps that WON'T make use of multithreading)

http://www.macworld.com/article/139507/2009/03/macpro2009.html
Very interesting article, thanks!

-- M
 

Mork

macrumors 6502
Original poster
Jan 9, 2009
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According to Gizmodo the i5/i7 up their clock speed when the extra cores aren't being used...so you might be better off with the Quad.(depending on you're usage.)
Way cool...

Quad core it is!

- M
 

johnrs

macrumors 6502a
Jul 7, 2008
520
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Nottingham - UK
The i5/i7 is generally going to be quicker that the C2D.

What I would think about is not what you will be doing today, but more on what you might be doing in 6 months time. I take it you will be wanting your iMac to last as long as possible.

People are correct in that you might not use the full potential of an i5 or i7 but this is new tech and 6 months to a year then you could very well be running programs that will benefit from from a Quad core

If you can afford to get the i5 then I would
 

Mork

macrumors 6502
Original poster
Jan 9, 2009
422
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The i5/i7 is generally going to be quicker that the C2D.

What I would think about is not what you will be doing today, but more on what you might be doing in 6 months time. I take it you will be wanting your iMac to last as long as possible.

People are correct in that you might not use the full potential of an i5 or i7 but this is new tech and 6 months to a year then you could very well be running programs that will benefit from from a Quad core

If you can afford to get the i5 then I would
Sounds reasonable.

Now, if MyEclipse (www.myeclipseide.com) will just start under VM Fusion in less than 5 minutes!

VM Fusion is coming out with version 3 that is supposed to be (of course) .... faster. We'll see...

-- M
 

Xibalba

macrumors 6502
Feb 20, 2009
322
0
Indiana, USA
As a software developer, I'm thinking getting the 3.3 GHz dual core iMac would probably be a good decision. 8GB should rock!

I'm not sure that the quad-core, with slower processor cores (albeit four of them...) would make that much difference.

How do you determine the dual-vs-quad-core decision?

Thanks.

- M
i can see that the consensus so far is that the quad core is a better deal - esp for a little "future-proofing"." i don't mind the extra $300 going from base model dual to quad core as long i won't miss out on the top end of the processor speed from being a little slower. i prob plan on doing the 8GB RAM either way.

i appreciate the information and welcome anyone else with more thoughts on comparing the new imac dual vs quad core...
 

Mork

macrumors 6502
Original poster
Jan 9, 2009
422
14
i can see that the consensus so far is that the quad core is a better deal - esp for a little "future-proofing"." i don't mind the extra $300 going from base model dual to quad core as long i won't miss out on the top end of the processor speed from being a little slower. i prob plan on doing the 8GB RAM either way.

i appreciate the information and welcome anyone else with more thoughts on comparing the new imac dual vs quad core...
And, having just checked the Apple site, I confirmed that the quad-core processor will be a higher clock rate for software that isn't set up to take advantage of all the cores.

Schweeeeeet!

-- M
 

js81

macrumors 65816
Dec 31, 2008
1,199
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KY
Since I'm kind of in the same boat, I figured I'd post my thoughts. (I plan on getting a 27" in the spring, if all goes according to plan...)

I'm tossed between the C2D and the i5 (i7 is just too much, unless something changes between now and spring). Here are my thoughts:

The C2D is a faster clock speed (3.06 / 3.33 vs. 2.66). Since many apps still don't take full advantage of mutli-cores, wouldn't a faster clock be faster? Or has Grand Central Dispatch in SL finally remedied all that?

Also, the i5 does NOT have hyperthreading. But it has 4 actual cores. The C2D DOES have hyperthreading, meaing that it will have 2 real cores and 2 virtual cores.

Here's my logic - since most apps aren't going to use 4 actual cores, wouldn't a C2D (w/HT and a higher clock speed) be faster most of the time? Correct me if I'm wrong... I've been debating this since the announcement.

EDIT: I forgot about the Turbo boost thing. Still, though, won't that make it just about equal? Turbo boost puts the i5 @ 3.2Ghz, BTW - right in the middle of the two C2Ds.
 

Mork

macrumors 6502
Original poster
Jan 9, 2009
422
14
Since I'm kind of in the same boat, I figured I'd post my thoughts. (I plan on getting a 27" in the spring, if all goes according to plan...)

I'm tossed between the C2D and the i5 (i7 is just too much, unless something changes between now and spring). Here are my thoughts:

The C2D is a faster clock speed (3.06 / 3.33 vs. 2.66). Since many apps still don't take full advantage of mutli-cores, wouldn't a faster clock be faster? Or has Grand Central Dispatch in SL finally remedied all that?

Also, the i5 does NOT have hyperthreading. But it has 4 actual cores. The C2D DOES have hyperthreading, meaing that it will have 2 real cores and 2 virtual cores.

Here's my logic - since most apps aren't going to use 4 actual cores, wouldn't a C2D (w/HT and a higher clock speed) be faster most of the time? Correct me if I'm wrong... I've been debating this since the announcement.

EDIT: I forgot about the Turbo boost thing. Still, though, won't that make it just about equal? Turbo boost puts the i5 @ 3.2Ghz, BTW - right in the middle of the two C2Ds.
I think the turbo boost is a bit faster than the 3.3 and if you have software that can take advantage of the 4 cores, then you should be ahead, right?

I'm not really sure about this either and there's not much user data since the machine isn't out yet.

I'm betting the quad core is the right choice, but like you, I'm really not totally sure.

You raised some excellent points.

-- M
 

js81

macrumors 65816
Dec 31, 2008
1,199
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KY
I think the turbo boost is a bit faster than the 3.3 and if you have software that can take advantage of the 4 cores, then you should be ahead, right?

I'm not really sure about this either and there's not much user data since the machine isn't out yet.

I'm betting the quad core is the right choice, but like you, I'm really not totally sure.

You raised some excellent points.

-- M
The i5 (using turbo boost) runs at 3.2Ghz. However, is the i5 faster per clock than the Core2? It DOES have more cache memory (6MB L2 for C2D, 8MB L3 for i5), so I would say that it IS faster. The 3.3GHz C2D 27" comes in at $1899. The i5 is $1999. Not much difference there...

I look forward to seeing some comparisons between the i5 and the base 27" (the 3.06).
 

Mork

macrumors 6502
Original poster
Jan 9, 2009
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The i5 (using turbo boost) runs at 3.2Ghz. However, is the i5 faster per clock than the Core2? It DOES have more cache memory (6MB L2 for C2D, 8MB L3 for i5), so I would say that it IS faster. The 3.3GHz C2D 27" comes in at $1899. The i5 is $1999. Not much difference there...

I look forward to seeing some comparisons between the i5 and the base 27" (the 3.06).
Why don't you consider the i7?

That's just a bit more and looks even faster...

- M
 

js81

macrumors 65816
Dec 31, 2008
1,199
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KY
Why don't you consider the i7?

That's just a bit more and looks even faster...

- M
'Cause then we're up to $2199. No way in the world the wife would let me spend that much. :D I'll be lucky if I can convince her to let me spend the $1599 for the 27" C2D (education pricing, I'm a teacher), and even at that I'll have to agree to sell my current iMac. So really, I guess its a moot point for me... here's hoping that by Spring the price will fall on the i5/i7 and/or refurbs will be out.
 

ntrigue

macrumors 68040
Jul 30, 2007
3,804
1
The i5 is 4-core and unable to hyperthread, but it does have the turbo boost when running a single core.

The i7 is recognized as 8-core in Windows as the hyperthreading virtualizes double the cores. 3.46GHz is a blazing fast single core speed! Snow Leopard and Windows 7 are going to encourage applications that utilize 4-core by the end of 2010.
 

js81

macrumors 65816
Dec 31, 2008
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KY
The i5 is 4-core and unable to hyperthread, but it does have the turbo boost when running a single core.

The i7 is recognized as 8-core in Windows as the hyperthreading virtualizes double the cores. 3.46GHz is a blazing fast single core speed! Snow Leopard and Windows 7 are going to encourage applications that utilize 4-core by the end of 2010.
Which is what makes me lean toward the 3.3 C2D. I can't afford the i7, at least not now. If I can 3.3 on both 2 REAL cores AND 2 VIRTUAL cores, would that be better than 2.66 on FOUR real cores? Yeah, the i5 could ramp up a single core to 3.2, but if I went with the 3.3 C2D, that should be faster most of the time, right?

BTW, $1779 for the 3.3GHz C2D 27" on edu. pricing.
 

Mork

macrumors 6502
Original poster
Jan 9, 2009
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'Cause then we're up to $2199. No way in the world the wife would let me spend that much. :D I'll be lucky if I can convince her to let me spend the $1599 for the 27" C2D (education pricing, I'm a teacher), and even at that I'll have to agree to sell my current iMac. So really, I guess its a moot point for me... here's hoping that by Spring the price will fall on the i5/i7 and/or refurbs will be out.
Do the prices ever come down that much?

Seems like they just come out with newer models...

:(

- M
 

js81

macrumors 65816
Dec 31, 2008
1,199
16
KY
Do the prices ever come down that much?

Seems like they just come out with newer models...

:(

- M
Na, price won't come down - but maybe the quad core will "trickle down" and Apple will make it standard (maybe make the i5 and i7 the two 27s and get rid of the C2D).

More likely, though, is the possibility of a refurb by spring.
 

iMacmatician

macrumors 601
Jul 20, 2008
4,249
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The C2D is a faster clock speed (3.06 / 3.33 vs. 2.66). Since many apps still don't take full advantage of mutli-cores, wouldn't a faster clock be faster? Or has Grand Central Dispatch in SL finally remedied all that?
Core i5/i7 is based on a newer microarchitecture than Core 2 so you get more performance per GHz.

Also, the i5 does NOT have hyperthreading. But it has 4 actual cores. The C2D DOES have hyperthreading, meaing that it will have 2 real cores and 2 virtual cores.
Core i7 does, but Core 2 doesn't.