How SQL database stores Rows, Data pages, extents, in disk and memory?

Question

I have data in table A as below

Assetid   attribute   value
    1546    Ins_date   05062011
    1546    status     active
    1546    X          10.4567
    1546    Y          27.56
    1546    size       17
    675     X          4.778
    675     Y          53.676
    675     depth      5
    675     st_date    06092010

I have data as above in table A. This table has many Assetids 1546,675,....etc. attributes might vary for assets.

I want output as below:

assetid  ins_date  status  X        Y       Size  depth  st_date
1546     05062011  active  10.4567  27.56   17    null   null
675      null      null    4.778    53.676  null  5      06092010

I have created Stored procedure, then called in Informatica to achieve this output. However, since i have large volume of data, it is taking much time to load.

Please suggest me other easy and best way to load it.