GPU only shows 3mb

[sgade]

My set up

Intel® Core i5-2500K - with intel HD graphics 3000 only shows 3 mb ram in system prof.
I have set bios to max - 512mb
How come the system is only showing 3mb?!?

I am trying to get my thunderbolt display to work with my set up:
Gigabyte GA-Z68X-UD3H-B3
Intel® Core i5-2500K
24 GB hyperX ram
Corsair H80 Hydro Series CPU cool
ASUS GeForce GT 520 1GB Silent PhysX / intel HD graphics 3000

My motherboard has a display port - i am trying to see if i can connect my thunderbolt display to the display port....
Els i have to buy a new graphics card...

 

[P1LGRIM]

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Note that intel HD graphics 3000 are unsupported in Mojave.