I would recommend against using the Fusion drive for the Global Performance Cache in CS6, since this drive contains both the operating system and application. If you're reading and writing data to the Fusion drive and using it as a cache, you'll bog the whole system down.
Ideally the cache should be on a drive dedicated to that purpose. Your question about USB3 leads me to guess that you have a laptop or iMac, in which case a USB3 should be fast enough with an SSD, theoretically you can achieve 500MB/sec transfer via USB3 but there are real-world limiting factors such as the hardware used for the USB interface and the top speed of the SSD. I'd recommend getting a 120GB SSD and a USB3 case for it.
My setup uses a Fusion drive in a MacPro. I have a separate 120GB SSD for the cache, but its internal. Prior installing the SSD I used a mechanical HDD for the cache. The SSD makes a huge difference.
I agree that ideally you'd have a dedicated cache drive, but I disagree with the strength of Ridley's first paragraph. In actual usage, reading from the disk for the OS and applications' operation (mostly application load and OS boot) happens at very different times than reading from and writing to a cache, so there is very little collision.
The thing that you absolutely want to avoid is having your cache on the same drive as yoursource footage or rendered output, since reading from and writing to those do happen at the same time as cache access.
"The thing that you absolutely want to avoid is having your cache on the same drive as yoursource footage or rendered output, since reading from and writing to those do happen at the same time as cache access." – Todd
Todd says it more clearly than I did – I meant the same thing but managed to mangle the sentence. I meant reading your source footage and writing your renders to the same drive as the cache drive.
I have seen what Todd talks about in his last paragraph. I can tell you from my experience with MacBook Pros that you get much better performance with a USB 3 or Thunderbolt drive as the Read Write source than you get when you have disk cache enabled on a single drive system like a laptop. Unless I plug-in an external drive I have Disk Cache turned off completely on my MB Pro. With the external drive, or better yet 2 external thunderbolt drives the MBProR is amazingly fast. Except for very small projects it's my standard configuration.
What capacity SSD makes for a good cache drive? While prices are coming down, they get pricey fast.
Should I add up the raw size of each layer in my comp and multiply by time?
1920 x 1080 x 32bpc = 28MB each layer
x20 layers = 560MB each frame
30 frames = 16GB per second
1 person found this helpful
I think that the 256GB and 512GB drives are a good deal: plenty of room for a project or two of cache files, even for a rather complex and heavy project.
It doesn't scale linearly like your arithmetic is suggesting, because of several factors---e.g., reused items are cached only once, each layer mayer have several history states cached, only things that take a relatively long time (relative to your measured disk write and read times) to render are cached.
So having the disk cache on the same drive as rendered exports is bad? I had read otherwise.
Perhaps you could help me with my next drive purchase? I currently have a Sandisk Extreme 120GB SSD system drive and a 1TB Seagate. I'm keeping my project files and media on the Seagate and the disk cache on the SSD along with the system install. I was going to purchase a 256GB Samsung 840 Pro to use for disk cache, media cache and exports, but should I not write exports to the same drive? Is there anything else you'd advise?
1. separate hdd for operating system and installed software.
2. separate fast ssd for active project and source files
3. separate fast ssd for cache.
4. separate drive, biggest u get, for final output
5. separate nas for archiving the projects after its finished.
Depending on project, could be not possible to get all the source media on the active project hdd but every project needs a bit of planning first, and if u need to work with float 32 HD exr sequences then u absolutely need to set proxy’s.( is old but i still use fnord j2k for making proxy’s for ae or premier, are extremly fast and small and have auto proxy feature and many more options and free http://www.fnordware.com/j2k/ )
Points 4 and 5 can be the same but i use a Nas in raid 1 for archiving, for security. This configuration is the best i found in years and works great with adobe suite and nuke and any software where lets you set the cache paths.
I had a SSD module and bought a $20 USB 3.0 external enclosure and it's plenty fast for a cache drive. I think it tops out at 200MB/sec, but that's only because the SSD is a from a couple years ago. I could probably get even more performance with a modern SSD (like the speedy Samsung 840 Pro at >250GB).
The Fusion drive is fantastic for the OS and apps. But everything else can be done one or two SSDs. Keep in mind, they don't really have any access time like an HDD and the bandwidth of the SSD with USB 3.0 is pretty amazing. So you don't need to split out every activity to a seperate drive. No offense, but I think Darvinius' method is a little overkill.