HP p410i array controller - what happens if i add memory?

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http://serverfault.com – I have a p410i array controller that only has 256ram. We want to create a raid 5 so we have procured a 512 write back cache module. If we install the write back cache, will this erase the existing raid information. The server currently has 2 disks in raid 1. 6 are spare waiting for an upgrade to create a raid 5. the concern is if we replace/upgrade the memory for the controller, we will wipe the existing production raid 1 array. Thanks in advance. (HowTos)