Reducing Umbraco memory usage by enabling 32-bit applications

Enable 32-bit applications in IISSo enabling 32-bit applications within Microsoft IIS for the application pool behind an Umbraco installation, will make it use a LOT less memory!

Looking at the statistics for many websites that have been running in standard 64-bit, the applications used to use around 600 MB of RAM, however with 32-bit applications enabled, you will notice that it will use around 130 MB. After some research, I found that this is because the garbage collector runs more often for 32-bit applications, simply because a single application can only address 1 GB of RAM/memory. Putting this information to use, you can assume that the 64-bit applications whilst using a lot of memory would release it if the system needed it.

I've noticed that sometimes you get chucked out of the back office, after some reason, though after some research I found a thread about an Umbraco installation that also looses its session intermittently.

In short, looks like you can sort the session problem by storing it in a cookie instead of memory:

  <sessionState mode="StateServer" cookieless="false" timeout="20" /> 

I'd be interested to know what other people think of enabling 32-bit applications on Umbraco.

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Tags: Umbraco

Luke Alderton


After 2 days of massive outages on my site, changing to 32 Bit App seems to have sorted it out. I was experiencing 95% Memory and CPU Usage with only one site running and one application pool dedicated for the site. Thanks for the post!
Sotiris Filippidis
I've also noticed impressive differences between using 32 and 64-bit application pools for Umbraco. With 32-bit enabled, application pools seldom go over 300-400MB, while in 64-bit they'll go as high as 1.5GB.
Thanks for the post man. one of my our website used to take 10 minutes to load after restart and used to consume 1.2 GB to 1.5 GB of memory. After this fix, not it is within few seconds and the memory usage is 450-500 MB :) :)
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