Xslimmer Revisited


A few weeks ago I mentioned my reservations about Xslimmer, which I got for free from the MacAppADay promotion. Several people chimed-in with the same fears, so I definitely was not alone in my paranoia. But I backed my system up, launched Xslimmer, and dove in head first.

I went through just about all of my Applications folder (with a few exceptions) and slimmed down a ton. A feature I’d request would be to see a log of those things I’ve slimmed, as well as MB totals (something like TextExpander that shows you how much time you’ve saved, for instance). Anyhow, It saved me around 100mb. Not HUGE, but a nice chunk, and larger than I expected.

An immediate observation was that upon launching Firefox, it was a lot snappier. Loaded up quickly, and launched several tabs much faster than it had pre-Xslimmer. So the light bulb went on…I put Photoshop CS3 in Xslimmer, and it previewed a nearly 50% slim-down – about 140mb. The final count was a 100mb slim-down. Launching Photoshop CS3 before Xslimmer clocked-in at around 6-8 seconds on my 2ghz/2gb MacBook. A huge improvement over the non-Universal CS2. After being run through Xslimmer, Photoshop CS3 now opens in 3 seconds flat. Sweeeeet.

So I guess you could say, I’m now sold on Xslimmer. Speeding a Photoshop launch to 3 seconds totally put me over the top.

EDIT: Stian had a good point in the comments. I re-opened PS CS3 without rebooting, which used OS X’s cache which made it appear to launch quicker. Though even after rebooting, It still fell to a solid 5 second launch time vs the previous 6-8 seconds. Any improvement is good with me!



Ok but Photoshop CS3 is blacklisted in the current version of X-Slimmer so cannot be slimmed.


disclaimer: I’m one of the developers behind Xslimmer.

@Rafael: TrimTheFat (TTF) is indeed a nice app. However, as already mentioned for Monolingual, I believe it targets a different audience. Even if the end result was the same, we have put a lot of effort in making Xslimmer an easy to use, reliable and even reassuring tool everybody can use. We understand that a few software developers choose to perform integrity checks on their apps for whatever the reason, and thus we understand that modifying application binaries can become a sensitive operation. That’s why we have taken every measure to exactly show the user what Xslimmer is doing at any given time, and providing fail-safe mechanisms in case some application refuses to start because it detects its files have been modified. We show in detail what slimmable applications have been found, what’s the operation progress, where the backup has been saved, what the projected savings will be. We also provide a downloadable “blacklist” with all the applications known to not work properly after being slimmed down, to avoid most users the hassle of inadvertently slimming troublesome applications. By default, we refuse to slim down applications found in system locations such as /System /Library or /Developer. Others have found this to be true, as you can read about in http://themacmind.com/2006/12/18/great-os-x-software-xslimmer/ or in this comment posted in a previous story about Xslimmer in this same blog: http://theappleblog.com/2006/12/08/xslimmer-at-macappaday/#comment-83230

Besides safety features, it is worth noting that Xslimmer development is pretty active. We tend to release new features every other week, and have a solid roadmap planned for the future months. Some features that have been included lately include: Growl notifications, installing and slimming from .dmg files in a single step, dropping apps to be slimmed to Xslimmer’s dock icon, showing the history log of slimmed applications, allowing the user to report troublesome applications to be considered for the blacklist, many UI improvements, etc. Some noteworthy features we are working on include localization, removing unused language packs, or providing a “wizard” to detect newly installed applications suitable to be slimmed down.

So, if you test Monolingual or TTF and they suit your needs, by all means go use them (of course). If, on the other hand, you feel more comfortable with the approach or features offered by Xslimmer, we’ll be glad to welcome you and offer our support and continued development.

@others_asking_about_performance: We developed Xslimmer as a tool to reclaim unused space taken up by your apps, and have been working under the belief that any performance gains would be negligible. However, we have received a lot of reports from users stating that they do see noticeable faster launch times. Therefore, we have decided to conduct an analysis that we will share with you (it’s not that we don’t rely on mississippi-counting, but we’d like to measure the amount of improvement, if any :).

Jeff Harrell

I’m totally talking out of my butt here, but assume for a second that the system loads the entire executable portion of the program into RAM before running it. In that case, it would take longer to load a Universal binary than a single-architecture binary, simply because it’s larger.

Of course, I don’t think that’s how it works. I was just taking a wild stab at it.

And yes, 28 seconds, a figure obtained by the highly scientific method of me sitting here and going “one mississippi” over and over again. If I actually used a stopwatch, I’m sure the number would be different. Unfortunately I can’t try again tonight. All I can tell you is that it takes about one second for the “Sorry, your trial period has expired” window to pop up. My PS CS2 license is at the office.

Kevin Ballard

I’m pretty confused, how does slimming apps make them launch faster? It’s pretty trivial for the OS (and, later, dyld) to figure out which architecture you want – the Mach-O header specifies where the data for each architecture lives. So removing one of the architectures really shouldn’t make any difference in speed.

Are you sure it’s not just psychological?


Monolingual does not allow you to select the applications you want to slim. If you are not careful, it lets you remove essential files in your system rendering it unusable (Rosetta can be destroyed, for example). It requires the user to select from a confusing list what architectures should be preserved, making it possible to slim the Intel code in an Intel machine. It uses a static blacklist of troublesome applications, instead of a dynamic downloadable one. It does not perform backups.

All these issues are solved in Xslimmer. Xslimmer is easier to use, more informative and clearer. It is also smart enough to detect the architecture it is running on and act accordingly. It provides you with detailed information about what applications can be slimmed, how much space will you save, or if an application is known to cause problems after being slimmed down. Xslimmer is not yet able to remove unused language files, but this feature is being developed currently.

From my standpoint Monolingual is a GUI on top of a low-level tool meant for administrators, whereas Xslimmer is intended for all types of users. If you are looking for a pleasing, reliable and user-friendly way to save some space, use Xslimmer. If you know what you are doing, Monolingual can do the job for you.

And, by the way, the newest version of Xslimmer does include a log of the files you have slimmed.


I just remembered… if you do use Monolingual, make sure you read the Monolingual webpage first, with their note about not stripping the System frameworks – because otherwise you break Rosetta.


1 second! Wow! Unbelievable! Incredible! Amazing! Unreal! You are kidding us! What a productivity gain! Get real! Stupendous! Out of this world!

Nick Santilli

Jeff – wow, 28 seconds? Sounds more like CS2 launch times. (ok, that’s a bit generous) I wonder if there’s any correlation between items that start upon logging on that may be slowing it down additionally for you.

Jeff Harrell

That’s absolutely right. On my Macbook (also 2 x 2.0 GHz, 2 GB) it takes a disgusting 28 seconds to launch PS CS3 from first click to usable program the first time after a reboot, and three seconds the second time.

This will probably vary depending on what fonts you have installed and how much free RAM you have on second launch.


Did you reboot between the tests? From 6-8 to 3 seconds on photoshop sounds a bit too wild, more like cached in RAM if you ask me.

OS X (like most modern OSes) caches recently opened files in RAM, this gives you faster response on files you’re working on.

To do this test properly:
1. Start and time program.
2. Run Xslimmer.
3. Empty cache (reboot).
4. Start and time program again.

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