Will a RAMDisk improve Carrara rendering time?
cryan_1832017
Posts: 0
Hello all.
I'm contemplating setting aside some RAM on my Carrara 8.5 rendering machine for a RAMDisk -- maybe 12 GB, since RAM is getting so cheap these days.
Does anyone know if this will significantly improve rendering time if the RAMDisk is set as the location for Carrara temporary documents?
Thanks.
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Good question. I've never tried it. You could give it a shot.
Whenever I check resources during renders, my 16 GB RAM is barely working, while my eight cores of cpu are trying to explode with heat ;)
It has been said that, to improve render times for Carrara - the best enhancement is more cores and faster cores in cpu. Adding great graphics cards has been sworn in to aid in setup performance, smoothing out your OpenGL in the work space as you build your scene.
The developer at Dogwaffle told me the same thing - get more and faster cpu before thinking about 'me' getting more RAM. Faster Hard drives - he said that too. I'll be going SSD sometime soon. Until then, I like my ultra large 6GB/sec SATA drive. More room make for easier, faster targeting. But I've heard people say that they could really tell the difference going to solid state drives. We'll see.
I have been told that making sure that you do not have a drive reading and writing to itself at the same time is important for speed as well.
In my system I have separate drives for programs, for data, for audio and for video. I make sure to render to the data drive so that the program is read from the C drive, the audio files are read from the E drive, the video files are read from the F drive and the render is written to my D drive. Like you, I also have a retinue of external drives for archival and backup purposes as well archiving important stuff to Blu-Ray discs.
Although, I have read that the life span has been improved for SSD drives they DO have a limited life.
Interesting. I checked the resource monitor (Win7Pro) during a render, and see that no more than 7GB of RAM is being used. The CPU is working as hard as it can, and there is a *lot* of disk activity.
So using a RAMDisk for the Carrara temporary files instead of writing to the physical disk might make a real difference.
I'll go ahead and compare render times for the same Carrara files with and without a RAMDisk. (Gimme a day or two for the results).
I am assuming what the OP means by RAM disk is allocating physical RAM as a virtual disk. It's not an SSD. I've used them in the past on my old Mac (mostly as an experiment) and they really do speed things up, but there's a couple of trade-offs in my experience: You can't use that RAM for anything else. Also, you need to make sure that there's a place to save the data to when the computer is shut down, and then it needs to be reloaded into RAM when the computer is restarted. My old Mac had this ability, but I haven't really looked into it for my current version of OS X.
Another trade-off was data corruption and stability. Granted, this was using Mac OS 9, which was the last OS before OS X, and it's Unix underpinnings, so maybe the stability has increased for Mac versions. Can't speak to Windows machines.
Using a RAM Disk for a scratch disk may be a good experiment, as when you quit Carrara, most of the contents should be erased. Unless Carrara crashes.
To the OP, if you try it, I wouldn't do it on any mission critical scenes, or if you have a deadline to meet. Heck, I'm kind of curious myself now. I may try it if I can figure out how to set one up again.
So I can set up a RAM disk using the Terminal in OS X. I set up an approx. 2 GB disk. I loaded a simple scene using NLA clips, a V4 and bikini with jiggle deformers and a customized procedural shader that uses functions such as color gradients, noise functions and reflections. I use a large spherical image in the scene's backdrop slot to provide reflections and a simple color in the backdrop to hide the background.
Here's a screen shot of Carrara's RAM use and scratch disk, which shows a lack of disk activity, meaning the computer isn't reading or writing to disk. There is a 2 MB or so spike when I activated the screen shot function.
Okay. I set up an 8GB RAM disk on my Win7Pro64 machine (using RAMDisk software - http://memory.dataram.com/products-and-services/software/ramdisk).
I then set the Carrara preferences for the scratch disk to use the RAM disk instead of the physical disk for temporary files. No other changes were made on the system.
Then when I rendered a movie that took 8:05 minutes before installing the RAM disk, it now takes 8:00 minutes -- a bit more than a 1% improvement. The resource manager showed a huge reduction in disk activity, though.)
I haven't yet tried setting anything in the Windows system to use the RAM disk. Not sure if there are any other ways to configure Carrara to take advantage of the RAM disk (which operates 300 times faster than a physical disk, according to the software manual.) The RAM disk is apparently most beneficial for databases, virtualization and thin-client software -- so maybe Carrara isn't optimized to take advantage of a RAM disk.
Here's a free virtual drive program for Windows: ImDisk
I've only used it for the ramdisk functionality and it seems to work fine. It's also open source, if that sort of thing matters to you.
I haven't tested ramdisks with Carrara though.
if you run the application from a ram disk, that is installing the app to the ram disk, it will open faster and some gui processes are faster. other than that no advantage to a ram disk. doesnt do anything for cpu intensive work or screen redraw
It's really more of a curiosity or an intellectual exercise.