14 Replies Latest reply: Mar 14, 2011 11:21 AM by clickmyface
Rory Smith Level 1 (5 points)
I am looking at purchasing a new 13" macbook pro and hope for some definitive advice on the above issue.

It seems to me both models are dual core processors with potential for 4 virtual cores and turbo boost. Apart from the increase in MHz is there any other fundamental difference between the two processors? Do they handle multitasking differently? What is signified by the different model name other than a straightforward speed boost?

I have almost decided on the i5 with benchmarks putting the difference between the two at only c. 15% but I am worried I am missing something fundamental. Any advice much appreciated.

Message was edited by: Rory Smith

PowerBook 12" 1.33GHz and Mac mini 1.42GHz
  • Michael Black Level 7 (20,416 points)
    I recall reading that hyperthreading is disabled on the i5 and enabled on the i7. Also bigger cache (I think) on the i7 to handle the potentially twice as many simultaneous threads.
  • kmac1036 Level 4 (2,360 points)
    this might help: http://www.anandtech.com/show/4205/the-macbook-pro-review-13-and-15-inch-2011-br ings-sandy-bridge/3

    if you can I would still go for the i7. it's going to serve you better in the long run as more apps are threaded & need more power.
  • Rory Smith Level 1 (5 points)
    Apple's website confirms that all MacBook Pros support hyper-threading.

    Anandtech highlight the key differences between the two: the i5 has 3MB L3 cache as opposed to the i7's 4MB, and that AES-NI support is lacking from the base model.

    What do these two things mean in real terms? I'm really interested in understanding the tech involved here.

    Thanks for the help so far.
  • kmac1036 Level 4 (2,360 points)
    AES-IN is hardware exceleration for disk encryption. Lion is said to be supporting full disk encryption, so this will come into play helping performance of that. the turbo boost is faster on the i7, this was designed to kick in when apps aren't multi threaded or multi-core aware, so performance doesn't drop with those apps.

    imo, I see the axe falling at some point & it's going to be between cpu models like this. it's sounding like 10.7 will only support Core 2 Duos & later, leaving the core solo & regular core duos out. I can see the possibility of apps (hopefully years from now) supporting the i7 but not the i5.
  • Michael Black Level 7 (20,416 points)
    Intels little list - you're right, in the second gen chips, cache seems to be the big thing. The AES-N1 thing is an improved chip instruction set that Intel proposed a couple of years ago to speed up encryption and decryption. Would make a difference if running wholly encrypted hard drives or such but otherwise, I don't know what it's good for.

    The cache issue I'd think would not be huge for a lot of users. Things I can see it making a difference in is if you work with large databases (queries and such may be noticeably faster with more cache?). Video editing too I suppose where you are moving a lot of data for long periods of time between cpu and RAM.
  • Rory Smith Level 1 (5 points)
    Am I being stupid, or are these then fundamentally the same chip with different clock speeds? Beyond some increased support for encryption and a slightly larger cache I don't see why the i7 deserves a different name.

    If in future there was a cut off between i5 and i7 what would technologically be behind such a cut off other than speed difference?

    Are we really talking about the benefits of i7 only really being applicable so far down the line that the technology will have been superceded anyway.

    To my completely untrained mind I'm getting the impression that the i5/i7 is a marketing gimmick...
  • kmac1036 Level 4 (2,360 points)
    the ones in the 15" & 17" are quad core. makes a big difference in performance. mine ranks up there with the mac pros. that just wasn't the case before. my 15" was 2 years old & this new one is 3.5x faster or more, depending on what you are doing. just wow!
  • Michael Black Level 7 (20,416 points)
    I don't think you are being dense at all. Everything I read is that there are marginal differences in real world performance between the two. The whole i3/i5/i7 line has been touted in the press as a merketing experts dream, with little solid substance separating the i5 and i7 chips (at least when talking comparable physical core count and close clock speeds).

    Assuming you are like many of us and buy a new machine every 24-48 months, then I don't think you need worry too much about the choice.
  • kmac1036 Level 4 (2,360 points)
    there may be some of that, I'm not totally disagreeing with you... a lot of this comes from the el-cheapo pc market where they need a reason to buy parts & resell cheaper than the rest. sort of like the celeron was - a cheap option. yeah, making a chip & then disable half it's features sounds counter-productive to me...
  • clickmyface Level 1 (0 points)
    Hey Rory,

    I have the 13" i7, but based on the 15% geekbench increase over the i5, I'm not sure the extra $300 is particularly worth it. You do get 180GB more in HDD storage however.

    A better use of that $300 would be to get two things: a large external HDD for backups, which I view as necessary so if you don't already have one, do it. Second, a Wireless N Router. Apple Time Capsule gives you the wireless router and 1TB of storage all in one, for $299.

    Here are Intel Spec Breakdowns (from the Horses Mouth):

    i5, http://ark.intel.com/Product.aspx?id=52224
    i7, http://ark.intel.com/Product.aspx?id=52231

    Besides 2.3Ghz vs. 2.7Ghz, here are all the differences I noticed:

    1. Turbo Boost: i5 2.9Ghz, i7 3.4Ghz
    2. Cache: i5 3MB, i7 4MB
    3. Bus/Core Ratio: i5 23, i7 27
    4. Graphics Max Dynamic Frequency: i5 1.2Ghz, i7 1.3Ghz

    5. Intel® Virtualization Technology for Directed I/O (VT-d): i5 no, i7 yes
    6. Intel® Trusted Execution Technology: i5 no, i7 yes
    7. AES New Instructions, i5 no, i7 yes

    I didnt know what #5 and #6 were, here is what Intel says:

    Intel® Virtualization Technology for Directed I/O (VT-d) extends Intel's Virtualization Technology (VT) roadmap by providing hardware assists for virtualization solution. VT-d continues from the existing support for IA-32 (VT-x) and Itanium® processor (VT-i) virtualization adding new support for I/O-device virtualization. Intel VT-d can help end users improve security and reliability of the systems and also improve performance of I/O devices in virtualized environment. These inherently helps IT managers reduce the overall total cost of ownership by reducing potential down time and increasing productive throughput by better utilization of the data center resources.

    Intel® Trusted Execution Technology for safer computing is a versatile set of hardware extensions to Intel® processors and chipsets that enhance the digital office platform with security capabilities such as measured launch and protected execution. Intel Trusted Execution Technology provides hardware-based mechanisms that help protect against software-based attacks and protects the confidentiality and integrity of data stored or created on the client PC. It does this by enabling an environment where applications can run within their own space, protected from all other software on the system. These capabilities provide the protection mechanisms, rooted in hardware, that are necessary to provide trust in the application's execution environment. In turn, this can help to protect vital data and processes from being compromised by malicious software running on the platform.

    Message was edited by: clickmyface

    Message was edited by: clickmyface
  • Rory Smith Level 1 (5 points)
    Thank you all so much for the advice. I am increasingly feeling validated that i5 is the way to go, particularly if these models signify the last gasp for this model MacBook Pro.

    So excited to finally be abandoning my PowerBook. Emotional attachment is no longer enough to justify living life at a technological snails pace!
  • kmac1036 Level 4 (2,360 points)
    what do you think the size & weight difference is between the 12" & 13"? I haven't heard people complaining as much about missing the 12" since the 13" MBP came out...
  • Humancapo Level 1 (5 points)
    I just recently switched from a 12" Powerbook to a 13" MBP. While I like the increase in speed and the brighter screen, I prefer the footprint of the 12". Most of my time is spent on the road and smaller/compact is usually better... The 12" is/was a true road dog.
  • clickmyface Level 1 (0 points)
    Over the last 11 years I had the 15" Titanium PowerBook G4, then the 12.1" Powerbook, then the 13" White Macbook, and now the 13" MBP. The 12" Powerbook was by far the best portable I have ever owned. Perfect size, sturdy, great material.

    And yeah, in terms of speed, the new MBPs are insanely fast compared.