Upgrade RAM on ReadyNAS Duo

It isn't recommended anymore because RAM manufactures like to change components on the sticks without changing the model number making them incompatible. This could cause serious issues (data loss & not booting to name a couple).

That being said I use Corsair VS1GSDS333 1GB in my Sparc units. I don't really see any noticeable speed improvements but the faq says they've seen a 12% speed increase.

If you do decide to increase your RAM, make sure to run the memory test at least twice.

I see a recent post that says the Corsair is now causing problems. I tried a Crucial stick that other had found success with, and it did pass multiple memory tests, but hung *hard* repeatedly in operation. I've ended replacing the original RAM and the unit is fairly stable again (cross fingers).
I'd like to see Netgear sell a certified upgrade, I'd certainly be happy to send them my money for a few percent improvement in performance.

They used to sell a 1GB RAM upgrade for the NV+ v1 (should also work in the Duo v1) but I think they've discontinued it now.

The RAM upgrade doesn't make much difference. If you want better performance get an Ultra and transfer your data across your network to it. The Ultra comes with a much faster CPU and 1GB RAM installed.