Blender runs out of memory while rendering fabric hair on GPU Yes, I do know there are 2 other similar questions to this one that have been answered here, but I believe this might be a different problem since I've not seen it or heard about it behaving this way anywhere else.

So I followed Andrew Price's tutorial on how to make towels to test towel physics and particles for other scenes. After finishing the tutorial I did a test render, only to have the surprise of my render displaying an "Out of memory" message and not much time later crashing. 

This is pretty much what happens:


After pressing the render button, the objects are being synchronized, the BVH is built, etc.
Then after roughly 4 minutes of calculating (no sample has been rendered at all), the render suddenly cancels leaving the simple message of "Out of memory" on the top tab.
And then after that, PC lag starts to intensify, just a little while later crashing Blender.


I had a similar issue before on an older computer (only difference is that blender crashed in seconds, the problem was I was using a 32-bit OS which did not work, quite at all, for cycles hair.)

Since the problem might I also be my computer, here are some of the details:


OS: Windows 7 64-bit
RAM: 4GB
GPU: NVIDIA GeForce 840M 2048MB DDR3
CPU: Intel Core i5-4210U 1.70 GHz 2.40 GHz


I've tried rendering this on my CPU with 128 samples, it taking 10 minutes to calculate and around 20 to render, so if I did a test render, then done some little tweaking for an actual render, then rendered it again it would take +1 hour to render just a simple towel. An architectural bathroom scene (which is what I was currently working on) would take an immense amount of time rendering with such limitations.

So what I'm asking is: What is it that causes this running out of memory? And are there any ways I can still render this hair on GPU, mantaining a reasonable rendering time?

I know I made this description waaay too long, but I want a clear enough description for a clear enough answer.

Here's the .blend file if it helps.
@Wiirexu That simply means that the 2GB of VRAM you have on your GPU is not enough for the scene. If you want to render the scene using your computer's available RAM, you have to render with CPU. If you render with CPU and there is still not enough memory, your only options are to get more RAM, or use a render farm.

You do not have enough VRAM available on your GPU for rendering the scene you are trying to render. Your only other options are: 

You could try reducing the amount of geometry in your scene using the decimate modifier.

You could switch to CPU rendering. This will render your scene using your available RAM, instead of VRAM.
(If you render with CPU and there still isn't enough memory, you will need to add more RAM to your system.)

You could use a renderfarm service, such as SheepIt! (Free)

You could upgrade your current GPU or add another to your system.

You could ask someone to render it for you (I'd probably be willing, I've got 6GB of VRAM)