Which of these two hard drives is best for SD-only video editing?

Question

Before I begin, I will start by saying that I realize the BEST hard drive is generally one's internal drive... but, ignoring that, my question is this:
I have 2 external drives available, and can't afford to buy a new one yet. Which of them is best:
1. 7200RPM drive, connected via FW400.
2. 5400RPM drive, connected via FW800.
I guess another way to phrase this question is, which is the more important factor, rotational speed, or connection method?
Just wondered, as I do not have a 7200RPM drive that can use FW800. I want to use the best of these two until I can afford to get a 7200RPM FW800 drive.
Thanks for any insight, and happy new year!

Answer 1

William,
A few people had chimed in great advise, but I like to add my own. Perhaps you will find this useful.
The speed of the hard drive these days are hardly measured by the spindle numbers anymore. 7200 or even 5400 means really nothing other when it was made. That's the same as saying that my old 2.4Ghz Macbook is going to be slightly slower than a new 2.4Ghz Macbook or Macbook Pro. So just looking at the spindle rate is one thing. You need to look at drive generation, link speed, cache size, platter size and platter amount. For example, today's Seagate 7200 RPM drive is at 7200.12 and last year was 7200.11 (a disaster year for them as the drives would click themselves to death!)
Let's start with link speed. The reason why internal drives are faster (at least with the all in one iMac, Mac Mini and Macbooks) is the fact that even at SATA I, it can operate up to 1.5Gbps, which is fast. FW800 is no match against SATA II at 3Gbps and SATA III at 6Gbps. Secondly, the throughput is well sustained with the help of DUAL PROC (Dual Processors) available on 2 Western Digital Blacks (one in SATA II and the other in SATA III flavours!). Digital Blacks come in 500, 640 and 1Tb. BUT, there is a Seagate most fastest drive in the 7200RPM category that is a 2Tb Barracuda XT which has a SATA III interface, though I doubt mechanical drives will achieve such high rates. These drives will simply saturate a FW800 interface port easily.
When we are taking about throughputs, the 60-70MB/s the 5400RPM puts out is only good for the first 30 to 40% of its capacity, because they lie on the outer platter. As the head moves in, the throughput drops. This is a problem with a single drive. However, if you RAID 2 small drives together, then not only your throughput will more than doubled (saturate the FW800), it can be sustained for more than 40% of its stored capacity. Which is why RAID drives are used by professionals. It's easy to built a RAID drive. You can even buy one from the store. So if you want to buy a 1Tb drive, then you will be buying a 1Tb drive in 2 500Gb hard drive sizes RAIDed together.
Another method I use if I only plan to have 1 drive is to "Short Stroke" it. Short stroking is very popular in the PC gaming world. Basically, what they do is run a program like HD Tune to determine what the best sweet spot that would give maximum throughput before it drops. Say a 500Gb gives the best speed for 140Gb, then they would go into BIOS and force format the drive to 140Gb. For
yourself, you can partition 2 drives. First partition would be the smallest and that can be your "render" drive. The second partition would be for storage. It's quasi short stroking, but this will give you the most throughput if you need maximum speed for real time SD video editing.
And Tom is right, always have a separate drive for rendering and never rely on your internal. However, if your internal happens to be 2.5" laptop drive, you can stick in a Seagate Momentus XT drive with its 4Gb SSD cache, it's enough to reduce disk access to the main drive so that's what I use for my Macbook. That's my read and OS drive and the Firewire 400 as my render drive and it's barely doable. FW800 would be nice!
Good luck on your purchase!
Message was edited by: Coolmax