Scratch Drive question

everything here says the internal is better. what leads you to think otherwise?
keep in mind that the optical drive usually runs on a sata1 speed and that can slow it down a bit.

I did the same thing with my old macbook. It was awesome.

My 2 cents.

I use the same setup for my MBP. I am not exactly sure what you are asking but here is my 2 cents.

What options are you contemplating? A different internal drive? A better external? As I mentioned I have the same setup and can not notice a difference between my SSD and HDD in FCP X. Yes things like copying files are faster on the SSD but for actually working in FCP X the difference is negligible. Forget the numbers they are not always right. What do your experiences tell you? Is your external drive 3.5 inch? Has the internal drive been in use for a while? A full format on the internal might improve the results. Often external drives have a larger cache size. Have you compared the specs for each model?

1920 × 1080 in ProRes 4:2:2 with PCM audio requires approximately 16.77 MB/s or 59 GB per hour. Video for the most part should not require tons of random R/W's and more likely it will be R/W's in larger chunks. Obviously the CPU/GPU have a greater impact on the video side. From my own experiences with Apple and the optical drive replacement, it does not always do what you expect. For example my SATA III SSD would negotiate at SATA II speeds in the CD bay but when I put it in the factory HD location it would negotiate at the full SATA III speed, even though both are SATA III capable.

Now for your question, "Based on these results, should I consider not using the internal drive as a scratch drive? Any other recommendations?"

Again forget what the numbers say, are you satisfied with the performance in FCP X? Yes you can get better results in the test with other drives but what are your needs? My planned upgrade path is a replacement for the drive in the CD bay with a 960GB OWC Mercury Electra SATA II SSD its current price is $1,117. I don't have high hopes for getting the full SATA III from my CD bay drive so I am ok with a SATA II drive, plus SATA III SSD's in the 1TB variety are well over $2000. I am however very happy with the performance of my current configuration and until I start shooting RAW video I not in a hurry to upgrade.

For external drives there are many possibilities out there but thunderbolt will be the best for performance. We have a 12 TB Promise Pegasus R6 RAID array using Thunderbolt at work, and it is the fastest drive I have ever used. Personally I am thinking about getting a Drobo Mini if the price would come down a little bit and it gets favorable reviews. If you don't know the Drobo Mini holds four 2.5 inch HD drives and one mSATA drive. It can be configured in a RAID or JBOD using the mSATA for a cache. As the price of SSD's come down you could build an array made entirely of SSD's, put that in your XBench tests and smoke it.