we often hear about  laptop or desktop Memory upgrade  , but perhaps you seldom hear or may not understand whether it is needed or not , and if we ever need a desktop or laptop memory upgrade then we have to understand many things , such as what type OS we use ,  what type of memory that can be instal in a   laptop/desktop's motherboard

W7-64 and W7- 32 is different characters , you can just put as much as 4GB of memory if you are using W7 - 32 , in contrast to W7 - 64 that can support much more memory than  W7 - 32.almost 192Gb
It would be useless if you install 8Gb memory  in a desktop or laptop that you are using W7 - 32 as the OS , because the OS will only detect less than 3.7 Gb .
And do not forget the specs or the type or speed of memory that can suport by the motherboard , if you install two memory types with different specifications  each other it will  easily to damaged motherboard . make sure you are installing or upgrading memory appropriately and as needed.