ISO performance tips for editing 4K video

mistergarth Posts: 32 Just Starting Out*

I recently made a major upgrade to my camera gear. I bought a Lumix G9. Previously, I'd been doing my videos on an ancient Canon Vixia HFS-100. Not only do I now have the option of shooting 4K, but the upgrade opens up a whole Pandora's box of possibilities with color profiles and grading.

Here's the problem though: my trusty old iMac*, which edits 1080 footage just fine, slows to a crawl when I try to edit 4K footage in Hitfilm Pro. The Viewer just hiccups and glitches and herks and jerks. I can put clips on the timeline, export the series, and look at it, but I can't really tell what I'm doing with any careful editing.

Buying a new computer right now is not an option; I over-extended myself financially with the shooting gear.

Are there any tricks to make this work, or should I stick to 1080 for now?

I've looked through the archives a bit trying to find answers to my question, but haven't found much that's applicable.

* Late 2015 5K iMac, 64GB RAM, 3.3GHz Intel Core i5 processor, OS 10.14.6

thanks in advance,



  • Triem23
    Triem23 Posts: 20,511 Ambassador
    edited January 22

    You can try turning off automatic Timeline Caching in File>Options>Cache.

    You can try lowering Viewer Resolution to 1/2 or 1/4.

    Otherwise, there's not much more to do. You have an aging integrated GPU and 4k footage has four times the pixel data of 1080p. There's really no way to get around that.

  • GrayMotion
    GrayMotion Posts: 1,613 Enthusiast
    edited January 22

    I got to interject.

    First. I'm a long time iMac user. I'm also a long time user of FCPX , Motion 5 and Hitfilm Pro.

    Your 5k iMac is plenty powerful to handle 4k . Your iMac should have a Radeon GPU w 2GB VRAM. That is plenty. Hell , one of my iMacs (Late 2013 Nvidia 1gb VRAM) can still handle 4k just fine. The problem is the software you choose to do your editing. Hitfilm Pro is the problem.

    I'd suggest the first chance you get, once funds are available, is to get a copy of FCPX. Use software that is made and optimized for your Mac. You'll get 50 times the mileage out of the "ole iMac" if you use Mac software. The plain old truth.

  • Triem23
    Triem23 Posts: 20,511 Ambassador

    @GrayMotion can't argue with that.

    Ah, didn't think to double check the specs... Been a very busy day at my end.

  • mistergarth
    mistergarth Posts: 32 Just Starting Out*


    It looks like I'll be sticking with 1080 for now. At least I can practice color grading the Vlog-L footage and get good at controlling contrast.

  • mistergarth
    mistergarth Posts: 32 Just Starting Out*


    Hmmm... that's very interesting. I've been reading about using proxies for editing. I bought HF Pro 13 or 14 months ago, and didn't download V17, which supports proxies, fast enough. Now I'm supposed to buy HF Pro all over again. Ain't happening.

    I've been looking at other editors which support proxies. For whatever reason, I hadn't really thought about FCP, but now that you mention it, Apple software should be optimized to squeeze the best performance out of an Apple computer.

    I'm gonna give Davinci Resolve a spin for the moment while I save my nickels.