Recommended/Maximum amount of RAM for ASA5520

Unanswered Question
Jul 29th, 2010


i would like to know, whether it is possible, to run 2x2GB (4GB in total) in an ASA5520?

The installation guide shows 4 DIMM-Slots. So actually it should work to run an ASA with

4Gig of RAM, shouldn't it?

The Release Notes of the 8.3 firmware release just wants to have 2GB, but why not putting

more RAM into the ASA? Maybe 8.4 wants to have more of it.


I have this problem too.
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Jennifer Halim Thu, 07/29/2010 - 07:32

The increase in the RAM requirement is because of the major change in the NAT feature, and a few more new features available in version 8.3, hence the increase in the RAM.

As off now, I don't see that there will be any major feature transformation that would require extra memory.

Magnus Mortensen Thu, 07/29/2010 - 19:13


     It is not advised to upgrade without using the approved Cisco memory. Also you should not upgrade past the documented memory value for the 5500 platforms as they have not been tested with those amounts of memory and may not be supported.

- Magnus

Christopher Ursich Mon, 08/02/2010 - 15:15


Do I understand correctly that 2 GB is the maximum supported RAM in the 5520?

I am upgrading from the original 512 MB using ASA5520-MEM-2GB= . Since my ASA has 4 slots, I am wondering if I can simply add the upgrade DIMMs, and result in a total of 2.5 GB.

Thanks, and see you on the podcast.

Chris Ursich

Magnus Mortensen Mon, 08/02/2010 - 18:16


     As noted in the following document, the memory upgrade for the 5520 brings it to 2GB:

Will it run fine with 2.5GB? Maybe, it has not been tested. Will the performance with that memory configuration be as good as it would be with 2GB? Not sure, as it hasn't been tested. The memory upgrade option was tested and designed in such a way to preserve performance. While it may work fine, it is not something we can garuntee or support as it has not been tested and signed off on by the supporting business units. As a result, the reccomended memory upgrade would be to 2GB.

- Magnus

Nagaraja Thanthry Mon, 08/02/2010 - 18:33


To add to Magnus's reply, there is a bug filed (CSCtg94369) related to leaving the old memory in the firewall while upgrading the memory to 2GB. It was observed that the firewall reboots if you leave the 512 MB of memory in the ASA along with the 2GB.Also, it was observed that the firewall reports wrong numbers when reporting available/used memory. So, at this point, I guess the maximum memory the firewall supports is what is officially documented.

Hope this helps.



Magnus Mortensen Tue, 08/03/2010 - 14:06

Chris,      We're glad we could help. If there are no further questions on the matter, please go ahead an mark this thread as 'answered'.   - Magnus


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