Performance Recommendations

Our recommendations for setting your performance preferences.

Modifying the performance preferences can help improve your FlowJo experience if you have sufficient hardware. Below are the general recommendations for performance preferences settings on Mac or PC with varying amounts of RAM. We recommend having at least 4x the amount of RAM as the size of data being loaded into FlowJo at the same time for analysis.

How to Modify Performance Settings in FlowJo v10

If you have sufficient RAM installed, then the default performance settings may be increased to improve calculation speeds on large data sets. This can be accomplished in two steps:

Step 1 – Allocate more system memory to FlowJo :

1. Click the Heart Icon in the top left corner of a FlowJo workspace window.
2. Choose Performance in the bottom row of the Preferences window that pops up.
3. Within performance Preferences
   • Set the Max Sample Cache Data size – This is the maximum amount of FCS data that can be stored in memory. If exceeded, some files get booted out of memory. We suggest to set this to ~1/2 times the total RAM installed on the computer. On a PC, the default value here is set to work for a computer with minimal installed RAM, but can be adjusted accordingly if more RAM is installed.
   • Set the Engine Request Cache size – This is the number of request/response pairs that FlowJo keeps in memory so it does not have to do the work again.
     • If 32GB of RAM is installed, set this value to 5000.
     • If 64GB or RAM is installed, set this value to 10000.

Step 2 – Allocate/allow the FlowJo client to utilize more memory:

Step 2 PC Instructions:

On a PC, this is accomplished by modifying and replacing the FlowJo10.lax file, which is located within the FlowJo 10 program folder.

1. Quit/exit FlowJo
2. Navigate to the FlowJo 10 Program folder. The default install location is C:\Program Files\FlowJo 10
3. Save a copy of the FlowJo_V10.lax file on the desktop
4. Open the FlowJo_V10.lax file in a text editor program
5. Search for/Find the following line of code: lax.nl.java.option.additional=-Xmx8192M
6. Modify the line of code to increase the total amount of RAM that can be utilized for the Java Virtual Machine environment.
   1. If 32GB of RAM is installed, the line can be modified to read: lax.nl.java.option.additional=-Xmx16384M
   2. If 64GB of RAM is installed, the line can be modified to read: lax.nl.java.option.additional=-Xmx32000M
7. Save the change
8. Replace the existing/original FlowJo_V10.lax file with the modified one. (Requires admin privileges)
9. Restart FlowJo

Step 2 Mac Instructions:

Increasing client memory allocation beyond 32GB is not possible on newer Mac operating system releases because the info.plist file within the Mac Application Contents folder is code signed, and modifying this file manually will invalidate the code signature, resulting in failure of the application to launch. 

This modification may be performed on older Mac OS. Please contact flowjo@bd.com for instructions if you would like to attempt this change.

Please note that many reports of poor performance can be traced to analyzing data off of a network or cloud based storage drive. These services can cause serious issues if not managed properly. We always suggest bringing data to a local drive for analysis, then saving to the network or cloud drive for long term storage and archiving.

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