Hi,
i’m going to get a new gpu and i’m going for a gtx 580. I’m wondering of 1.5gb is enoug or should i get the 3gb? As i am a beginner i probably won’t render any really big scenes in the near future. Is it right that the main problem would be large textures?
Main problem would be Textures but also big Meshes, Render layers add also to it.
I recommend you to have 2 Graphic cards any way in it, otherwise the system itself is going to use memory too. (set 1 low end gpu for Monitor, 2nd 580 for Cycles)
You can Render quite a bit with 1.5 Gb, but if you need more, you might hit a wall, depending on how strong your cpu is. Have rendertimes 5x (or whatever) slower just cause it doesn’t fit in you gpu? Might be worth those 200 (or whatever) Bucks… i would go with 3 or 4 GB…
In recent Blender Version Cycles shows you how much Memory it uses. Look top left when you Render (in the UV/Image Editor, set to Render View). Make some Tests.
And, just for your information, some 580 with fans go up to +40db, which is quite loud. (Water-cooling 
I am like not a technical person but what exactly is vram?
Is the the memory of the graphic card?
Yes. vram is video ram
Personally, I wouldn’t waste my money getting a 1gish card, even 2gb.
The problem is simple; you cant just add more ram to your gfx card.
My current scene in blender, that is rendering, is using 3gb and has peaked at 3.5; system memory is currently at 10gb. I use cpu as don’t have nvidia; one of the reasons is that my scenes can often use more than 3gb.
Only 4gb cards from nvidia I know of are 6 series, and I’m waiting to see what will happen with the Intel phi card, and nvidia’s next gen card; and who knows, amd actually might get their drivers working properly (doubts it will happen).
so basically the scene is using 3 gb ram of your graphics card or your computer, as you said that you dont have a graphic card and you are rendering with your cpu??
Like I personally might buy a 2gb vram card as I myself am a beginner and dont have really large scene to render but they could be large enough for e.g to render this scene how much vram would it take?
Like will a 1.5 or 2 gb nvidia can handle it atleast or not???
Like can a core i5 or i3 with 8gb ram and gtx 660ti handle that scene?
The Island Scene doesn’t take too much memory, but thats cause it’s basically just one tree, just instanced a lot which doesn’t use much more memory… It peaks at 150MB. I would not take this as a reference…
Rogper’s Opel GT uses 800MB
still, i would go with 3 GB 580. Just imagine the Situation where you’re working on your nice Scene to find out it’s too big and then have to go back, deleting, optimizing, make textures smaller, split into different Scenes, all that Headache… for 200 Bucks?
4GB is only in 6xx Series, afaik. Since 580 is faster (for cycles) i would consider it just for 4GB.
well actually the problem is I cant afford a 580… I am looking for the best config in my budget…
you can say my budget is around $600
So should I look for greater VRAM or greater cuda cores???
As the computers ram is very cheap I can afford 8 gb ram. But will that 8gb ram help in the scene or the scene is calculated on the graphic card’s ram…