how to get graphics card memory info? windows and linux shows different value

In my Windows 8, video card shows 640 MB of available memory (Screen Resolution > Advanced Settings or with dxdiag). But ubuntu (with lspci command) shows 256 MB. so who's right?

1- install sysinfo :

sudo apt-get install sysinfo

and then run it -->

sysinfo

2- Alternatively use :

sudo lshw -businfo | grep -i display

find your exact graphic card model and check the manufacturer website

3- there are other command as well like :

sudo apt-get install hardinfo

Hope that works ;)

Step 1. lspci | grep VGA Note down the numbers at the beginning of the output line. E.g 00:02.0

Just for information: this number provides the domain, bus, slot and function parameter for your graphics card [[[[<domain>]:]<bus>]:][<slot>][.[<func>]]

Step 2. Insert the above number after -s parameter So if the number was 00:02.0 then the command will be lspci -v -s 00:02.0