Better to save processed vid to a different h/d than original file?

[brassplyer]

Besides my main system C: drive, I have 2 additional internal drives D & F. If I'm using Virtualdub to process a file that's say on drive F, seat of the pants logic tells me that instead of saving the processed version back to drive F, saving it to drive D should be a bit quicker since it doesn't make the F drive have to both seek data from the original drive and redeposit the new version elsewhere on itself.

However, not being a techie I realize there could be factors I'm not aware of, things I have a misunderstanding of, etc.

What say you?

[edDV]

It depends whether your CPU can process faster than the drive can read-write.

Used to be the CPU was the bottleneck so the disk had plenty of time to seek. It is now possible to process say SD MPeg2 at 2x+ play times. This isn't normally a problem for a single drive unless the drive is fragmented but is getting close. Seek times may cause the drive to become the bottleneck.

Best to test both ways for processing times. A single drive will chatter more due to the seeks.

[guns1inger]

Generally yes, it is a good idea, and will produce some speed improvements. These improvements are greatest if the two drives are also on different controllers/channels.

FWIW, I always use different drives for source and target material

[redwudz]

Yes, your logic is correct. I use three hard drives with most computers I build. Boot, Edit and Archive. Slowest is using only the boot drive for everything. The boot drive is accessed almost constantly by the OS, so that slows down transfers.

With some operations like encoding, it doesn't make a lot of difference as the encoding is usually slower than the slowest transfer rate of the drives.
But with editing and other operations, using multiple drives does make a bigger difference.

Other factors are the seek time, cache size, and read/write time of the drives. The HDD controller also factors in, but the drives themselves are usually slower than the controllers.

[edDV]

The extreme is real time processing which requires 1 or more play rolls while recording the ouput all at the same time. This requires separate channels (minimal seeks) from and to a very fast RAID server.