I'm running Apple Mail 5.3 and Thunderbird 17.0.4 on Mac OS Lion 10.7.5. The system I'm running those apps it's an iMac with 3Gb of RAM and 2.4 GHz Intel Core 2 Duo.

I run both applications at the same time and I got those results looking with the Activity Monitor.


As you can see, Apple Mails consumes a little bit less than Thunderbird but uses more virtual memory.

My question is, which one has better performance? Apple Mail or Thunderbird? I ask this because that was a puntual test, and I don't know if they get stressed when looking for RSS feeds or email on the inbox.

Do you know any other mail app which works better looking on the performance?

  • 2
    What is your definition of performance? It could be defined in many different ways, e.g. memory usage, which is what you looked at, but also speed to negotiate with POP3/IMAP/SMTP servers with or without SSL/TLS; speed to fetch and index new mail, search speed etc. It may also depend on the mailbox sizes. It is quite possible that one of them is better based on some criteria, and the other -- based on others (although I haven't done any tests). – lupincho Mar 12 '13 at 11:40
  • I´m looking to memory optimizations. But could be great to know which one handles better the POP3/ SMTP negotiations. Thank for the comment :) – axierjhtjz Mar 12 '13 at 12:06

In general, Apple Mail should perform better than Thunderbird. This is for a few reasons. Apple Mail is built using Apple's current development platform, Cocoa. Cocoa allows for access to more recent, native APIs on the Mac: things such as OpenCL, Grand Central and Core Animation. It is also programmed natively in 64-bit mode. And lastly, Thunderbird is no longer being developed and has an older code-base.

What this means to you is that Apple Mail can take advantage of the built-in hardware, allowing software to do less of the number crunching, and giving you better overall performance. It will also allow you to use more memory (though it is unlikely any Mail program will regularly need more than 3.5GB of memory).

This explanation does not take into account any additional tasks one mail program may do over another, such as using a plug-in for Apple Mail.


usualy mail applications all lay around the same in preformance and memory depending on size of inbox, file sizes, nr of RSS's there are many variables, but the general thing is they only use enough to have an impact on performance, whenever they are grabbing new information! (not even then) but in order to minimize CPU usage you should set "grab mail" too manual

as far as tip on good mail client.. check out sparrow!

  • I used Sparrow before on the iPad and the impression it gave me was a good one. But they left the project aside after the Google´s purchase. About what you said of grab mail, what I'm looking for is the memory performance. But thanks for the tip, y didn't knew that the auto refresh consumed CPU. – axierjhtjz Mar 12 '13 at 14:10
  • no problem good luck finding what you are looking for! you might want to consider running mail in a browser? i dug a little deeper and seems that sparrow got messed up sense google bought them! – Macmaniman Mar 12 '13 at 14:18
  • in fact I think I´ll have to format the iMac. But right now I'm on a project and I´m limited on that option :). Thanks anyway ;) – axierjhtjz Mar 12 '13 at 14:20

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