FCPX: what is CPU-driven and what is a factor of SSD-speed

[DoctorK4]

Trying to determine what processes are driven by the speed of the CPU and which are more dependent upon speed of HDD/SSD and/or RAM.. Pretty sure I'll be getting an i7 but maybe an i5 will do.

Exporting from FCPX uses CPU but what about...

- scrubbing video in the timeline?
- playing a preview of an edit with transition/ effects in the 1/4 size preview window
- playing the same preview full-screen
- layering three or four video and/or audio tracks in FCPX

 

[simsaladimbamba]

It depends on what codec you will be using with your footage and if you will allow FCP X to optimise the footage, meaning to transcode the imported footage from a non-editing-friendly format to a very editing friendly format.

If it is the first, the CPU will be taxed more, if it is the latter, the SSD will be taxed more, but it is also advised to use external storage for the footage to edit with, USB 3.0 HDDs should suffice.

This may be of interest:

And while the following is a bit older and does not tangent FCP X, the same principles apply:
Video Compression
Why It Matters & How To Make The Most Of It

which includes the following sections:

• GOPs, Macroblocks & Wavelets
• Acquisition Formats
• Editing & Post Formats
• Final Cut Pro
• Avid Media Composer
• Adobe Premiere Pro
• Which Codec Should I Edit With?
• Conclusion
• Camera Codec Summary
• Apple ProRes Variations
• Avid DNxHD Codecs

 

[DoctorK4]

Wow, thanks for all the detail. Frankly it's just 1080p video shot on an iPhone (vacation videos mostly) so not the highest quality stuff. I'll read through those links and try to learn a little more.

 

[simsaladimbamba]

Wow, thanks for all the detail. Frankly it's just 1080p video shot on an iPhone (vacation videos mostly) so not the highest quality stuff. I'll read through those links and try to learn a little more.

The iPhone records its video with a highly compressive codec called H.264 to keep down storage space. That also means, that FCP X and the CPU also have to do a lot more work to play the footage and make precise edits, since the footage does not contain every frame. As you mentioned using FCP X, I presume, it is better to know how input and output is generated and what goes where.