Object link data with modifier

I cannot find answer anywhere else…
Could somebody tell me why object instances “link data” with modifier are putted in gpu many times.
I have scene with about 350 dices. When I trying to render it via cycles Gpu mode I’m getting out of memory. Thought its strange because in viewport it is light… So I found when I deleted subsurf from all dices its getting 350 times less vram memory. Is it normal that objects with modifier are stored apart for gpu?
Any trick to have subsurf? I already tried link modifiers… same result…

Use linked duplicates (group instance, dupliverts/faces, particle system) and remove/apply subsurf if necessary.

Thanks for reply, I’m using linked duplicates, but its seems when they have modifier, renderer split them when calculating subsurf… I have used rigid body to throw them into bowl, then make them real and again I’ve linked them to be sure they are same geometry, when i change 1 in edit mode rest is also changing, but when it came to render with modifier they are separate for vram… Without moldifier they goes as 1 geometry…