Why my Graphics memory shows half on banchmarking softwares when using latest driver of Intel?

[TSija]

My motherboard is http://http//www.asus.com/Motherboards/H81ME/ Asus H81M-E, processor Intel Core i3 4150 @3.50ghz, graphics memory: 2 GB built in(Intel hd 4400) and the latest driver of this driver in Asus website is V10.18.10.3412.. But intel is updating the driver regularly..

I installed Intel's latest driver for this hardware and all the benchmarking software even http://www.cpuid.com/softwares/cpu-z.html CPU-Z shows that my graphics memory is only 1024 MB ..But when I install the driver provided by Asus, all these softwares show the correct information(2048MB).. I can use the Asus provided driver but it's too old(released on 2014/3/14) ..they don't update regularly..Then what's the problem of the driver provied by Intel??what's the root of this problem?Do I have to stay with the old one?Thanks in advance.

*dxdiag report is in the attachment while installed the driver provided by Asus.

[Jose_H_Intel1]

The drivers provided by Asus* are probably customized for your system.

I recommend you taking a look into this article: http://www.intel.com/support/graphics/sb/CS-029090.htm Graphics Drivers — Graphics Memory FAQ for Windows 2000/XP/Vista/7*