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iMac i5 vs MP quad 2.8?
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It depends on what you plan to do with it.
It depends on what you plan to do with it.
To clarify, I think he's talking about regular versus custom applications that use multiple cores.
The iMac i5 is faster for basic single-threaded tasks (web, office). Yes, its clock speed is 100MHz slower, but (a) it's using the newer Sandy Bridge microarchitecture, which is faster clock-for-clock than the Nehalem in the Mac Pro, and (b) it has Turbo Boost to 3.7GHz, vs. 3.06GHz for the quad 2.8GHz Mac Pro.
In fact, if you look at the iTunes benchmark in this Bare Feats article, the 2.7GHz i5 beats the 3.33GHz hex-core Mac Pro and the 3.1GHz iMac i5. It ties the 3.4GHz iMac i7. That's because of Turbo Boost. For single-threaded performance, it's about as good as you'll get in a Mac today.
For multi-threaded apps, you'll see some benefit from the HyperThreading in the Mac Pro (or an i7 iMac), but I doubt it will outweigh the Turbo Boost advantage. Photoshop is unlikely to benefit from or really take advantage of more than 4 cores (whether real or virtual). I'm not familiar with Logic Audio -- it might. But again, the Sandy Bridge architecture probably more than makes up for a slight difference in clock speed.
In fact, if you look at the iTunes benchmark in this Bare Feats article, the 2.7GHz i5 beats the 3.33GHz hex-core Mac Pro and the 3.1GHz iMac i5. It ties the 3.4GHz iMac i7. That's because of Turbo Boost. For single-threaded performance, it's about as good as you'll get in a Mac today.
For multi-threaded apps, you'll see some benefit from the HyperThreading in the Mac Pro (or an i7 iMac), but I doubt it will outweigh the Turbo Boost advantage. Photoshop is unlikely to benefit from or really take advantage of more than 4 cores (whether real or virtual). I'm not familiar with Logic Audio -- it might. But again, the Sandy Bridge architecture probably more than makes up for a slight difference in clock speed.
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Logic uses all available cores and can be user specified with version 9.1.4. It is also one of the apps that can make a turd like the 2.26GHz 8-core seem really fast.
So the imac does not have hyperthreading?
Ok, so the MP will run Logic faster than the imac, but not regular applications that use less cores, correct?
What do you suggest I do. I was going to buy a hexacore mac pro but it seems like a bad time to buy it given that I don't urgently need it and that the new one is coming out soon. I don't know if my old PC laptop will take anymore, and if the new MP is going to be out next late this year, it is a long wait.
Ok, so the MP will run Logic faster than the imac, but not regular applications that use less cores, correct?
What do you suggest I do. I was going to buy a hexacore mac pro but it seems like a bad time to buy it given that I don't urgently need it and that the new one is coming out soon. I don't know if my old PC laptop will take anymore, and if the new MP is going to be out next late this year, it is a long wait.
Throw in 200.00 more for the i7 @3.4 and get all the turbo boost and hyperthreading. It will be closer to the 6-core currently in performance. Slightly slower but resale may be better as well.
In that case, it's a tougher call. I don't know which would perform better, but I'd be willing to bet it's within a 10% margin either way. The iMac's CPU, even when not Turbo Boosted, is probably faster per core because the improvements in Sandy Bridge trump a ~4% increase in clock speed. Then the only question is how much benefit comes from HyperThreading. Since you're gaining virtual cores, not real ones, it basically comes down to whether the CPU's ability to distribute work units to the cores is better than Logic's/Mac OS X's. It probably is a little bit better. It's probably not enough better to matter (i.e., it doesn't make your machine into a real 8-core machine like derbothaus mentioned). But maybe Logic users can clarify.
No, that particular iMac doesn't have HyperThreading. But I doubt the MP will be meaningfully faster unless Logic happens to benefit far more than most apps from HyperThreading, and it will likely be slower for every other purpose you've mentioned. The iMac i7@3.4 does have HyperThreading and a similar Turbo Boost to the i5. It's the best Mac Pro alternative in the lineup.
The 21.5" runs at 1920x1080 and has almost as high a pixel density as the 27". I have one on my desk at work, and things are noticeably smaller than on my 24" 1920x1200 monitor at home.
The other issue with the 21.5" is that you can't get the 3.4GHz i7, only the 2.8GHz (probably because there's less room to dissipate the extra heat than in the 27"). Of course, if you do want the 3.4GHz i7 as a refurb, you'll have to wait for the 2011 iMacs to show up in that section. Right now it's only last year's models (though the 2.93GHz i7 is a strong performer too).
There are a ton of factors but here goes oversimplified: If a quad 3GHz proc gets 100 tracks. Hyperthreading on that same chip should grab you 150 or so. Roughly halved or better in Logic. So a 4 Core with HT (8 Threads) will act like a 6-core. An 8-core (16 Threads) with HT will act as a 12-core.
http://macperformanceguide.com/Reviews-MacProWestmere-LogicStudio.html
Some extra testings. Only relevant for the 9.1.3 tests. Do not look at the 9.1.1 as there was a well known bug.
http://macperformanceguide.com/Reviews-MacProWestmere-LogicStudio.html
Some extra testings. Only relevant for the 9.1.3 tests. Do not look at the 9.1.1 as there was a well known bug.
Wow, that's quite an improvement, much more than other apps with HyperThreading. Sounds like that feature is worth it one way or another (Mac Pro or an iMac with an i7).