Video Card Ram causing stuttering?

johnnyjelkojohnnyjelko Website User Posts: 93


Just found out about hitfilm last week....amazing.

Now onto the question - I am getting a new video card for a computer I built a few months ago. I hope to buy it... tomorrow. And I think I'm going with an r9 390 8gb. I wanted to know how much the video ram effects the editor/compositor. 

As soon as I add one or two effects, the video playback is about 2fps.. and I noticed it's about the same on my work computer and home computer. So I'm guessing it's the vram because they are both similar spec wise as far as video ram goes..

Home PC: 

i7 5820k, 16gb ddr4, 240gb ssd, radeon 4850 512mb

Work PC:

i3, 4gb ddr3, 120gb ssd, hd graphics 2500


So can we chalk this up to the vram since I believe I'm at minimum? Kinda want to make sure I'm making the right decision on gpu. I 3d model too and am unbiased to cuda/opencl.

Thanks in advance!


  • NormanPCNNormanPCN Website User Posts: 3,945 Enthusiast

    It all depends on exactly what you are doing regarding exact playback performance. Some things are fast, aka real time, and some things never will be fast no matter what GPU you have.

    Some things are CPU bound and some things are single threaded (cores). For example, I just did a typo and entered 50000 particles per second, when I wanted 50. Oops. The CPU stayed at 12% (one thread) and the GPU was at zero. It took 20-30 seconds before I could change the typo back to 50. CPU bound and single threaded.

    The bottom line is you have to be 100% specific when you talk about performance. Just saying one or two effects is too ambiguous. Generally speaking a more powerful GPU helps.

  • Triem23Triem23 Moderator Moderator, Website User, Ambassador, Imerge Beta Tester, HitFilm Beta Tester Posts: 18,262 Ambassador

    Hitfilm uses the GPU for most rendering tasks, so, yes, that GPU will give you a massive increase in performance. As you already noted, your current configuration is just at minimum spec. 

    Cuda and Open CL aren't considerations for Hitfilm. Hitfilm sticks with Open GL. It might make a difference to your modelling software. 

    For Hitfilm work you've chosen a solid GPU. It's NVidia competitor is a little faster and has more overclock potential, but has less VRAM, and that 8GB will allow you to build bigger, more complex scenes. 

  • Triem23Triem23 Moderator Moderator, Website User, Ambassador, Imerge Beta Tester, HitFilm Beta Tester Posts: 18,262 Ambassador

    To build off Norman's comment, in general, Hitfilm uses the CPU for calculating particles and models... Maybe a few other things, but all rendering tasks are sent to the GPU. Even though you haven't been specific in terms of effects you've used, you are still going to see a massive speed increase with that GPU. 

  • johnnyjelkojohnnyjelko Website User Posts: 93

    Thanks for the great answers. The effects being used didn't seem to matter much when we're added to the time line so I didn't get too specific. But that is a good note and I'll try to pin down the difference in overclocking the cpu compared to gpu upgrade. As I believe I was using the 5820k at stock 3.3ghz... which is probably also in line with my work i3. I've had the i7 upto 4.2ghz without too much increase in temp and sound. So I'll be sure to see how much hitfilm appreciateso the increase there. 

    I was originally set on getting a 980 ti but the new baby is having me wait on that buy. And the 970 didn't  seem like it's vram would be good for me down the road since I don't even plan to game on it. Although I've read it's opengl is better than the 390..

    I'm just really excited with thus software. Love the learning curve compared to say adobe, much more intuitive.. for me at least.

  • NormanPCNNormanPCN Website User Posts: 3,945 Enthusiast

    Hitfilm is extremely GPU centric. I can hear it. By that I mean I can hear the GPU fans spin up, but the CPU fans mostly remain idling. It is a unique sound. At first I thought I had a fan bearing going bad, but I quickly realized it was the GPU fans solo from CPU which I never heard before.

    Most apps will only spin up the CPU. Video games spin CPU and GPU up all the way. Hitfilm really only spins up the GPU as it seems the primary task for the CPU in Hitfilm is to tell the GPU what to do next. The later seems to be mostly single threaded so a core fast clock rate is likely more of a help here than cores.


  • RobinRobin Website User, HitFilm Beta Tester Posts: 1,671 Enthusiast

    "it seems the primary task for the CPU in Hitfilm is to tell the GPU what to do next." Hehe. I like thought of my CPU standing in my computer and bossing around :D But seriously, it really depends on what you're doing - if you're busy pumping millions of particles into a scene the CPU will have so much to do with calculating the particle physics that it will have barely enough time to boss the GPU around. Also, video encoding and decoding all runs on the CPU, so a bad (read: delivery) codec will quickly bring the CPU too it's knees as well.

  • johnnyjelkojohnnyjelko Website User Posts: 93

    Hmm good info!

    I'm actually glad to hear it's very "gpu centric" because I debated for the longest time if I should get a 4790k for single thread performance or 5820k. But I'm very happy with my 5820k and it overclocks decently, quietly, and cooly.

    I ended up buying a r9 390 8gb this morning which should hold me over for a  year or two and then I'll probably grab myself a 980ti.


  • NormanPCNNormanPCN Website User Posts: 3,945 Enthusiast
    • "it really depends on what you're doing"

    Yup. I've mostly done pure CG particle stuff and I see my GPU at low utilization, and thus fans silent, as the particles setup seems to be single threaded. During all this only one CPU core is really doing anything and the one thread is pegged. So the CPU is the performance limiter for this specific stuff on my machine. A killer GPU would not help here.  There is room for big performance improvements here, which is a good thing. Worth any upgrade price.

    I've done other pure CG stuff without particles and my CPU was idling (4%) and the GPU was pegged and the fans start a blowin. A killer GPU would help here.

    Hitfilm does seem to put video decode into separate threads for each video file simultaneously displayed on screen. I would presume, I hope, that the particles compute thread is separate from video decode and UI and whatever other housekeeping threads exist.

    GPU = AMD 7950, CPU = 4770K 4Ghz

  • johnnyjelkojohnnyjelko Website User Posts: 93

    Thanks, I'm doing some benchmarking now to see where I'm making improvements. More so for the wife so she can see how I wasn't wasting money on gadgets..

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