Your machine is listed at http://www.crucial.com and it answers this question.
Bob
I have a HP Pavilion 7850 with 128 MB Ram...I would like to upgrade to 512 MB.
There is one empty slot...Do I install one 512MB in the empty slot and remove the 128MB or do I remove the 128MB and install 2 of 256MB?
Any help would be greatly appreciated..Thank you

Chowhound
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