3825 router wont boot after adding more memory

[JessicaBroy82_2]

I have a 3825 router that came with the default 2 x 256 sticks of memory. According to the Cisco website the router can be upgraded to 2 x 512 sticks to total 1 GB. I found that if I put 1 stick of 512 in the router it boots up fine. If I have 2 sticks of 256 it boots up fine, but if I put in 1 stick of 512 and 1 stick of 256 the router fails to boot at all. A console session to the router shows nothing but a black screen after waiting for over 5 minutes. Has anyone run into this before? Can I only install 2 sticks of memory if they are same size? I don't see anything on the Cisco website about installing memory in pairs.

Any help would be greatly appreciated.

Thanks,

Jessica

[lgijssel]

Yes, the memory modules need to be the same size.

http://www.cisco.com/en/US/docs/routers/access/3800/hardware/installation/guide/38comp.html

regards,

Leo

[JessicaBroy82_2]

Thanks. That happens to be one of the docs I didn't look at. :-) Appreciate your help!