I've found that to be true. And it makes sense, too, because the OS is CONSTANTLY accessing the hard drive - even when you are essentially doing nothing with your app(s). The other reason is that, in the case of PD, when you are rendering a project, the program is basically reading from your source drive, processing that info (rendering) and then writing the output to the same drive. And since those two locations - the source 'folder' and the destination folder - are not necessarily close to each other on the drive, the drive head has to go back and forth continuously between those two points. Not only does this slow your system down, but it puts more wear and tear on your hard drive. This applies to mechanical hard drives. SSD or RAM drives drives can randomly access any area of its storage (RAM) at any time and so the wear and tear is virtually non-existent (The flash memory used by SSD drives does eventually start breaking down, but that's another matter).
Because of the random access nature - and speed - of SSD drives, you can put your OS and PD source files on the same drive and still see large performance gains. Here's what I do: Since I only have a 250GB SSD in addition to my 3 mechanical drives, I only have about 50GB of free space on the SSD once I migrated my OS from my old mechanical OS drive to the new SSD drive with all of my installed programs, etc. So, I COPY (keep the originals in a safe place, always) my source files - all of them, including audio tracks, subtitles, whatever - to a folder on my SSD drive during the render. Once everything is done I delete the copies. This seems to have a significant impact on overall speed of PD, especially on HiDef types of projects.
Lots of system RAM is helpful, too. In fact, if you have a lot of it you can get a program such as DataRam's RAM-Disk (free for non-commercial use but limited to 4GB of 'storage') and use your own system RAM as an extra drive! And system RAM is even faster than SSD memory - by a LOT (DDR3 has a throughput rate of 6400 megabytes per second - Really fast SSDs have a rate of between 500 and 900 megabytes)! One downside to this approach is that system RAM is volatile - It will cleared when you shut the system down. However, DataRam's Ram-Disk has an option where it can copy its contents to your physical hard drive when you go to shut down and then do the opposite when you boot back up (copy it back into RAM). This can make shutdowns and reboots take a bit longer, but it may be worth it. [note: Windows 7 Home Premium and lower can only access 16GB of memory - no matter how much RAM you actually have installed. I found this out the hard way. You need Windows 7 Professional or higher to have access to all of it (up to 192GB!). If you have a 32 bit OS, then you will be limited to 4GB no matter what.]
Anyway, yes, I would highly recommend an additional drive for source files. If you instead migrate your OS to the SSD and use your old mechanical drive for the source files you will not only make PD faster, but your overall system will be much faster as well, including other programs you have. Loading of programs, for example, is virtually instantaneous. If I had another SDD for source files only, I'd be in heaven!
Russell1967
p.s. DataRam's RAMDisk can be found here:
http://memory.dataram.com/products-and-services/software/ramdisk (scroll down about halfway and click on the 'RAMDisk Lite' download button under the 'Personal Use Software' section).
p.p.s. The non-free version of the personal use RAMDisks from DataRam comes in 4 'flavors': 12GB, 24GB, 32GB and 64GB. The 12GB (which is more than I would probably need in 95% of projects) is only $9.99. Although it looks like it's a physical product on the website, it is actually just a program that supports a certain amount of RAM disk storage.
p.p.p.s. (Whew!) There's a totally free RAM disk program that supports more than 4GB called ImDisk. It can be found here:
http://www.ltr-data.se/opencode.html/#ImDisk
I don't know anything about it, but it may be worth a look if you don't have the $$ for the other RamDisk option.
This message was edited 1 time. Last update was at Jan 26. 2014 11:05
System specs: Windows 7 Professional x64; Gigabyte Z77-DS3H motherboard with i5-3579K 3.8Ghz processor with 32GB RAM; Zotac GTX 760 w/4GB; 1xWestern Digital 1TB 10,000RPM HD; 1x Samsung 840 Pro SSD System Drive