GarageBand CPU Test

Discussion in 'MacBook Air' started by nebulos, Aug 9, 2011.

  1. nebulos, Aug 9, 2011
    Last edited: Sep 30, 2011

    nebulos macrumors 6502a


    Aug 27, 2010

    This is a 'caveman test' i've been using to compare CPU performance for music apps on the new airs and other macs, like my 2.26 C2D Mini. i don't know how much this test actually says and can not guarantee its value!

    How to Run the Test: (results on other Macs welcome!)

    0. turn your volume way down or off and quit other programs (one browser window is okay).

    1. start GarageBand. select 'electric guitar', title your project (e.g., "CPU test"), and click create.


    2. double click the 'sustain' pedal in front of the amp on the right, then drag and drop the yellow and orange overdrive pedal onto it, (replacing the sustain). fill up all 5 slots with (same) overdrive pedals.


    3. engage the loop option next to play at the bottom. record 4 bars of nothing (red button). click on the recording and copy it (apple + c). create a duplicate track: apple + d. make sure the marker is at 0 and paste the recording (enter, apple + v). make 5 total tracks like this.


    4. open up Activity Monitor and order your processes by "%CPU" (click the tab on top). also click CPU below to get a visual indicator. check that your volume is down and hit play on GarageBand. note the average % reported for GarageBand. (ideally, have nothing else running that takes up more than 1%.)


    Results: Activity Monitor CPU% readings (approximate average reading)

    2.26GHz C2D Mac Mini = 136%*

    1.6GHz i5 11 MBA = 115%

    1.7GHz i5 13 MBA = 100%

    1.8GHz i7 1X MBA = 93% (thanks to happyslayer and KPOM!)

    2.3GHz i5 13 MBP = 70%


    Activity Monitor assigns a processor with "N" total cores, (physical + virtual) a total percentage of N x 100%.

    So my Mac Mini gets a total of 200%, since its a dual core processor. But the 2011 Airs get 400%, because they are dual core with hyperthreading; 2 physical cores + 2 virtual cores = 4 total cores.

    I was kinda disappointed by the results above until I remembered this; What the do the numbers above say?

    2.26GHz C2D Mini = 150%/200% = 68%*

    1.6GHz i5 MBA = 115%/400% = 29%

    1.7GHz i5 MBA = 100%/400% = 25%

    1.8GHz i7 MBA = 93%/400% = 23%

    2.3GHz i5 13 MBP = 70%/400% = 17%

    * Note on 2.26 Mini: Originally, I got 75% for the mini. I reran the test tonight (10.1.11) and the mini seemed to do a bit better, only needing 68% of its CPU to handle the test. CPU temp was steady at 68 degrees. Here's a pic:


    (sorry about the thumbnails)

    Attached Files:

  2. nebulos thread starter macrumors 6502a


    Aug 27, 2010
    anybody with an i7?

    i know it might look a little complicated, but the test should take about 5 minutes, including reading the directions.
  3. happyslayer macrumors 6502a


    Feb 3, 2008
    Glendale, AZ
    Followed you instructions exactly - Good instructions! - and ran the test. It does vary a bit, but when nothing else is running the CPU% hovers around 93% --occasionally dropping to 91 and occasionally hitting up to 95, but 93 is most common.

    Also, I still have the test running and my CPU is at 83 degrees C and the fans are now on at 3600 rpm. (As a reference, the Star craft 2 Demo heats my little 11 up to 93C :eek:)

    So, I am not sure what that will tell you. I guess it is a little more efficient than the i5 -- 93/400 vs. 100/400

    I had the i5 128 11.6 for a few days but realized I needed more HD space. So I upgraded to the i7 256 11.6 since that is all the Apple store carries. I must say that I am not in any way disappointed with this little machine. It will run anything I throw at it with flying colors.

    Anyway, let us know which you decide on.
  4. nebulos, Aug 9, 2011
    Last edited: Aug 9, 2011

    nebulos thread starter macrumors 6502a


    Aug 27, 2010
    thanks a lot HS!

    93%/400% = 23% for the i7 is about what i expected, but i did want to verify.

    i can't really wait for a shipment, so i'm also deciding between the stock i5 128GB or the i7 256GB. i would put the i7 to use, but the i5 may serve me fine too. i can get by on 128GB, but i do have a lot of 'stuff' and will be making much more. of course, i don't need to keep it all on my MBA, so i don't know. i will certainly get back with my choice though.

    anyways, thanks again! i know it's at least a little painful to read through a long set of instructions. i'm glad they worked for you.

    congrats on your machine!
  5. mac jones macrumors 68040

    Apr 6, 2006
    Wow, great thread!

    Not much difference between the i5 and the i7 for this it seems (which is good because I cheaped with the i5 :eek: )

    But what strikes me, is the HUGE difference going from the C2D, even at 2.16GHZ.
  6. nebulos thread starter macrumors 6502a


    Aug 27, 2010
    assuming the interpretation is correct, that is a big difference and shows how nice the new tech is.

    the difference between the i5 and i7 on the 11" is small in a way. on the other hand, its about 20%, so it could be significant if extrapolating remains valid. 20-25% seems to be the general figure that's out there, so this seems to corroborate.

    i'm really not sure how tough this test is though. maybe i can come back to this and compare with some other software later. GarageBand is, of course, the only thing i can conveniently test in the store. the question is how does one of these amp simulators, plus 5 pedals compare to [your favorite VST], for example.

    glad you liked the thread. i will try to add to it.
  7. nebulos thread starter macrumors 6502a


    Aug 27, 2010
  8. slpslee macrumors newbie

    Mar 10, 2011
    I'm an educator and, like you, I was hesitant to spend the extra $300 on the 11" because I was afraid it would be more of a "gimmick," or more similar to the iPad than a full-fledged computer. I was attracted to the small, light form factor, but I already have a 15" MBP, so the 13" Air seemed redundant.

    I bought the 11" i7/256 this past tax free weekend, and it's a great choice. It's really unique in that it makes a great business computer that's perfectly usable for long periods at a time, but it's light enough to hold in one hand and still be productive. I plan on keeping it much longer than I had anticipated, so the extra processor power and storage space will come in handy.

    I'm not especially GarageBand savvy, but I can guarantee it runs all my Aperture plugins which are fairly graphics-intensive with no problems. If you can spare the extra cash, I'd definitely go for the top 11". You'll be pleasantly surprised at how versatile it is.
  9. nebulos, Aug 9, 2011
    Last edited: Aug 10, 2011

    nebulos thread starter macrumors 6502a


    Aug 27, 2010
    sorry i keep rewriting this. i was trying to cover too much ground at once, i think.

    i think the i7 256GB is a fine choice. i'm also thinking the i5 128GB is a good choice too, considering you can probably get around the differences with a little work, and the difference in price can be spent elsewhere.

    i'm still thinking though. so i'll have to get back on this.

    anyways, thanks for your comments and congrats on your new Air!
  10. KPOM macrumors G5

    Oct 23, 2010
    The highest it hit was 96% on my 11" i7 running on battery power.
  11. nebulos thread starter macrumors 6502a


    Aug 27, 2010
    great, thanks. sounds like what happyslayer got above. about 93-ish on average?

    thanks for running it!

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