The Search for Universal Binaries

All of the applications that we've looked at thus far are Universal binaries, meaning that they are compiled to work on both PowerPC and x86 architectures.  And although the number of Universal applications is quite large, there are still quite a few that are missing.  The entire Microsoft Office suite, all of Adobe's products, and even Apple's professional application line have yet to be made available as Universal binaries.  All have been scheduled and committed, but we're still at least another month away from seeing their debut. 

Apple has done a tremendous job of making sure that non-Universal binaries do run on their new Intel based Macs, thanks to a binary translation program called Rosetta.  Apple has been extremely quiet about the specifics of Rosetta, in my opinion, because it is a temporary solution that doesn't perform very well and they would rather that everyone forget it exists and port to Universal binaries immediately than rely on it as a crutch.  The basic gist of Rosetta is this: when a non-Universal application runs its PowerPC assembly code, it is handed off to Rosetta, which then translates it into another form, optimizes it and then generates its own x86 code.  The code is also cached along the way so that frequently used code blocks run quicker, since they don't have to be re-translated. 

If you're familiar with compilers, this very much sounds like a real time compiler, except that you are going from low level assembly code to low level assembly code instead of a high level programming language to the latter.  And although the process works, it is primarily to ensure functionality and wreaks havoc on performance. 


You can tell if an application is Universal or not by looking at its info, the Kind: field will be listed as "Application (Universal)".

The other side effect to a Rosetta-style binary translation is that the amount of memory that you need goes up, sometimes significantly.  Let's look at an example. First, let's take a Universal application, in this case iPhoto, and look at its memory footprint:

  iMac G5 1.9GHz  iMac Core Duo 1.83GHz
iPhoto Memory Size (at Open) 20.48MB 21.24MB

On the iMac G5, the application, with no photos in its database, takes up 20.48MB of memory.  On the Intel based iMac, iPhoto '06 occupies 21.24MB.  We've already seen that the Intel based Macs do take up a little more memory when running the same applications as the PowerPC based Macs, so the differences here are expected. 

Now, let's take a look at a non-Universal application, Microsoft Word, that has to be executed using Rosetta:

 Rosetta Performance Comparison iMac G5 1.9GHz  iMac Core Duo 1.83GHz
MS Word Memory Size (at Open) 40.03MB 64.43MB
MS Word # of Threads (at Open) 2 3

At startup, with no open documents, Rosetta increases the memory footprint of MS Word from 40MB to just over 64MB - an increase of over 60%! 

Remember the PDF that we generated in our Pages benchmark earlier?  Instead of outputting it to a PDF, I exported it to MS Word and opened it on the two machines.  I timed how long it took to open the 116-page document, but first. let's look at how much memory MS Word is occupying:

 Rosetta Performance Comparison iMac G5 1.9GHz  iMac Core Duo 1.83GHz
MS Word Memory Size (116 page Document Open) 75.75MB 218.79MB
MS Word # of Threads (116 page Document Open) 4 5

The memory footprint of MS Word has gone absolutely insane, growing from "only" 60% greater than the native application on the G5 to just under 3x the size.  With the document open, the Intel based iMac had 218.79MB of its 512MB of memory being used by MS Word and Rosetta, compared to 75.78MB on the G5.  I stressed earlier that 512MB isn't enough once you start to seriously use iLife/iWork applications. Now it's worth amending that to include anything that requires Rosetta to run.

So, how long did it take to open the Word document?  Approximately 69% longer, thanks to the necessary binary translation during the process.  Since Rosetta operates in its own thread, I checked to see if having a dual core processor sped things up at all. Unfortunately, the gain is basically nothing. 

 Rosetta Performance Comparison iMac G5 1.9GHz  iMac Core Duo 1.83GHz  iMac Core Solo 1.83GHz
MS Word Document Open 27.1 seconds 45.7 seconds 47.9 seconds
MS Word Document Convert to HTML 36 seconds 114 seconds*  

I eventually mustered up the courage to do the unthinkable: convert the open Word document to HTML.  On the iMac G5, this process took a healthy 36 seconds; on the Core Duo based iMac running Rosetta, the process took 114 seconds and then crashed, leaving me without my HTML file.  No matter what I did, I could not get the process to complete without crashing. 

I turned to one more test of performance under Rosetta; this time, to see how Rosetta impacted graphics operations as well as some more CPU bound tasks.  Cinebench 2003 has yet to be made Universal, and as a scripted benchmark, it's very easy to generate and compare data that it produces.  I used the unoptimized (non-G5) version for both platforms to keep things as equal as possible. The results are below (scores are in Cinebench 2003's own units, higher numbers are better):

 Cinebench 2003 Rosetta Performance Comparison iMac G5 1.9GHz  iMac Core Duo 1.83GHz  iMac Core Solo 1.83GHz
Rendering-1CPU 203 76 75
Rendering-2CPU   143  
C4D Shading 246 103 101
OpenGL Software Lighting 634 182 185
OpenGL Hardware Lighting 1336 506 504

Once again, the inclusion of a second core doesn't really seem to speed up the translation process at all, with the Core Duo and Core Solo posting very similar scores.  The actual performance is absolutely abysmal, not to mention the serious performance hit when looking at the OpenGL tests.  In the OpenGL Software Lighting test, the Core Duo running the benchmark using Rosetta can't even perform at 1/3 the level of the G5. 

iWork '06 Performance with Pages and Keynote Final Words
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  • Illissius - Tuesday, January 31, 2006 - link

    Compared to native applications, obviously, it's less than ideal; on the other hand, compared to, say, PearPC, it's pretty amazing. (I don't have any data and haven't tried it myself, but from what I've heard I'd suspect it runs at 5%-ish performance; compared to that, 30-70% is a minor miracle.)
    I know it won't interest the end user any whether it could've been even worse, but wanted to point it out, nonetheless ;).
    Reply
  • yacoub - Tuesday, January 31, 2006 - link

    I wonder how it compares in game- oh, right, Mac. Hehehe ;) Reply
  • DrZoidberg - Tuesday, January 31, 2006 - link

    there is one very popular game on mac.

    World of warcraft....could anandtech pls include a benchie comparing mac with intel core duo vs g5 in wow? It would be interesting to see if apple switching to intel means macs are better at games (or not).
    Reply
  • fitten - Tuesday, January 31, 2006 - link

    Is the Universal Binary out for WoW yet? Reply
  • Cusqueno - Tuesday, January 31, 2006 - link

    I have a 20" iMac Core Duo and with the default 512 RAM it was bad performance. About 5-10 fps in IronForge and 20-25 elsewhere. When I upgraded to 2 GB RAM it has improved greatly, maybe 10 - 20 in IF and 30 - 40 on the road. I guess this is due to Rosetta using lots of RAM.

    As of last night, there was no Universal binary. But today is patch/reboot day so might be pushed when I get off work. It is supposed to be included with version 1.9.3 according to the WoW forums.
    Reply
  • fitten - Thursday, February 02, 2006 - link

    That's pretty awesome considering that you're running WoW in emulation (Rosetta). Reply
  • vortmax - Tuesday, January 31, 2006 - link

    Seeing that Rosetta is needed for all MS and Adobe apps. and since using Rosetta seems to take lots of memory, it would be nice to see how it runs with 1gb. Also, some benchmarks from Photoshop would be nice :)

    Thanks Anand!
    Reply
  • Lifted - Tuesday, January 31, 2006 - link

    "... but those are the ones we want to measure anyways so they have to be there." Reply
  • Eug - Tuesday, January 31, 2006 - link

    Does turning off one core turn off half the cache?

    ie. Is it really Yonah Core Solo, or is it Yonah Celeron M?
    Reply
  • maconlysource - Wednesday, February 01, 2006 - link

    Where did you get the toolbar single proc- dual proc utility.
    I installed the developer pkg on my Intel iMac but can't find it?
    Can you email me it?

    Thanks.

    Pete.
    Reply

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