Blackmagic Forum

Hello,

An amateur user here. We started using Livestream for our church and we have been using Davinci Resolve to edit our videos. I move to a mac(personal) from pc(church) to edit. Editing is better in Mac but when it comes to delivery it takes as much time as the PC. I'm not sure if it's a hardware or software issue or maybe a configuration that I can change in my mac to render faster. I just follow the same delivery configuration as the pc. I tried changing it to ProRes but still the same result. I tried optimizing the files before editing, same result. Was using Davinci 17, I downgraded to 16 the same results ( also because 17 is crashing a lot). Im happy using the mac for Davinci until I reach delivery. Please help.

PC
Asus Laptop
Windows 10
Processor Intel Core i7 -7700HQ CPU @2.80Ghz 2.81 Ghz
Memory 8 GB
Graphics Intel (R) HD Graphics 630 4166MB ( 128 MB dedicated video, 4038 MB shared)

MAC
iMac (21.5-inch, 2017)
OS Big Sur Version 11.2.3
Processor 2.3 GHz Dual-Core Intel Core i5
Memory 8 GB 2133 MHz DDR4
Graphics Intel Iris Plus Graphics 640 1536 MB

Both of these are underpowered for Resolve. Yo need better hardware or enough patience.

Uli Plank wrote:Both of these are underpowered for Resolve. Yo need better hardware or enough patience.

Template Response. If it works for him, then his hardware is good enough. He's asking why the Laptop is faster than the iMac in rendering, not whether or not you approve of his hardware.

He likely isn't doing anything beyond FHD, anyways, so his requirements - even using Resolve - are fairly meager given he's probably not using the Color or Fusion pages a ton... just cutting low-res footage and rendering out timelines.

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i7-7700HQ is faster than a Dual Core Core i5 (I5-7360U) from basically the same generation (That iMac is basically an ultrabook in an AIO formfactor - so way weaker than that laptop). 4C/8T on the i7 vs. 2C/4T on the i5 and higher clock speeds. Those iMacs also has slower RAM (2133MHz), which affects iGPU performance. 2400 vs. 2133 is a pretty decent difference: ~9% different in memory speed that directly affects iGPU performance, most likely wiping out any lead in performance the Iris Plus would have over UHD 630, and then some. Iris Plus isn't a massive upgrade over UHD 630.

UHD 630 doesn't have 128GB eDRAM. Only Iris Pro iGPUs had that, and Iris Pro only came with Quad-Core iMacs and MacBook Pro SKUs. Most Windows Laptops did not use Iris Pro, as the OEMs had SKUs with Nvidia MX350 dGPUs that are better for about the same amount of markup to the end user - it wasn't worth it, in most cases. UHD630 only has shared memory, so its performance is affected by System memory speed (and channel configuration).

That iMac is basically a huge MacBook Air.

Decode-Dominated workflows (everything on the edit page) can be sensitive to platform differences - like Decoder Quality, for example. However, Delivery is sensitive to differences in CPU performance to a much larger degree...

Since you're using an iGPU, the memory speed is a factor given how much Resolve uses the GPU. It's going to factor in. ~9% higher memory speeds benefit the UHD630 vs the Iris Plus. I'm seeing the UHD630 in that i7 having 9-10% higher Base and Boost Clocks, as well. UHD630 does not have 128MB eDRAM. Iris Plus has 64MB eDRAM.

It's also likely the i5 in the iMac will throttle under sustained loads before the i7 in the PC Laptop. This is a major factor in workloads like video rendering - especially when the i5 is throttling while the i7 is able to maintain clock speeds in the boost range - both CPU and iGPU.

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Those Dual Core iMacs were never a good value. It was always better to just buy a MacBook Air that you can take anywhere and then get a display to bolt onto it, or just save money and get a Mac Mini and your own display They were basically ultrabooks with an overpriced screen bolted to them, and lacking any and all portability and upgrade options (well... you can always risk opening it up and cracking a screen Apple will charge you $500+ + Labor to replace).

All correct, but I just hope that info will help him.

Thanks for the quick responses. I can see that it's a hardware issue. The iMac was a gift and pass the return period. They had good intentions when they surprise me with it. And I wish I saw the Apple hardware configuration beforehand as well. So my questions are:

For the iMac:
So moving forward, is there a system configuration that I can change to make it work? Most of the video edits that I do are up to 5 video tracks Multicam and light colour grading. So not a lot of heavy editing. Is there anything I can change in the editing setting or delivery settings to render it faster?

For the PC:
I will be lending it to someone else to help me edit. I'm happy with the delivery but not with the editing. Would upgrading the ram and HD to SSD will help?

Both would profit from some more system RAM. I don't know if you can expand it on your own on the Mac. I did it in my 27" model, but I'm not sure about the one you have.
And then, faster storage will help with multicam for sure. Get SSDs.
Finally, is your footage H.264 or 265? If so, transcoding would als alleviate the load.

Use them both. Set one up to remote render while you’re editing on the other one.


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For the iMac:

Are there settings or configurations I can change on the system to make it render faster like codec, and render settings?

What’s your sources codec and what are your rendering right now?

Uli Plank wrote:Both would profit from some more system RAM. I don't know if you can expand it on your own on the Mac. I did it in my 27" model, but I'm not sure about the one you have.
And then, faster storage will help with multicam for sure. Get SSDs.
Finally, is your footage H.264 or 265? If so, transcoding would als alleviate the load.

You can, but you have to open the machine up and practically disassemble it to access the RAM, as it's on the other side of the motherboard. This means you have to take off the screen and then remove a ton of stuff to flip over the section of the motherboard where the RAM slots are.

Absolutely do not recommend anyone do this themselves. Bring to a shop that you can hold liable if they break the machine. There is a very legit risk of damage. I've seen iMac screens spiderweb just while having the tape cut.

Uli Plank wrote:All correct, but I just hope that info will help him.

Best advice is to upgrade the PC to 16GB RAM, put SSDs in there, and use that to edit. Also, get Resolve Studio if you don't already have it - if you're using predominantly H.264/HEVC footage.

That iMac should not be outperforming that laptop while editing Intra footage in Free Resolve, so if that is the case then something else is the problem (like running the Windows Laptop unplugged with default battery power plans, etc.). The render performance difference indicates this, and even pushes the differences in iGPU power to non-factor territory.

It should only outperform when using compressed footage due to Decoder Disparities between the two platforms in Resolve's Free SKU.

What a pain with the RAM in that iMac! On the bigger model you just open a small cover in the rear and put it in by yourself.

Uli Plank wrote:What’s your sources codec and what are your rendering right now?

I'm editing multiple clips consisting of MP4, MOV and some images that are 1080 30fps.

Optimized Media and Media Render Cache:
Optimized Media Resolution Choose Automatically
Optimized Media Format ProRes 422 LT
Render Cache Format ProRes 422 LT

My render settings:
Format: Quicktime
Coded: H.264
Use hardware acceleration if available: checked
Resolution: 1920x1080 HD
Frame rate: 30
Quality: Automatic
Editing Profile: Auto
Entropy Mode: Auto
Key Frames: Automatic
Frame Reordering: Checked

Uli Plank wrote:What a pain with the RAM in that iMac! On the bigger model you just open a small cover in the rear and put it in by yourself.

Yes, it is compared to the other models where it's accessible in the back or the bottom. Though I know how to do it( worked in an Apple repair for a while ), I need to go to the Apple Store so I won't void the warranty.

Let me suggest this then: instead of getting more RAM for the iMac, get a SSD with enough space, connected by TB3. Set your cache to ProRes 422 HQ and your render to the same format, using cached material if available. I bet you'll get pretty fast renders.

Transcode to H.264 with Handbrake for final delivery and compare which one is faster for this step.

Uli Plank wrote:Let me suggest this then: instead of getting more RAM for the iMac, get a SSD with enough space, connected by TB3. Set your cache to ProRes 422 HQ and your render to the same format, using cached material if available. I bet you'll get pretty fast renders.

Transcode to H.264 with Handbrake for final delivery and compare which one is faster for this step.

He's using a HDD on the Windows PC and still getting slower render speeds on the iMac. The bottlenecks in the iMac rated: CPU > GPU > RAM > Disk.

The drive he's editing off of is, frankly, the least of his worries. You can hook a RAID of NVMe disks over TB3 onto that iMac and he'll still eventually run into CPU/GPU/RAM bottlenecks. The Windows Laptop will still render faster off of a Laptop Drive, because the storage is not the issue. The slow CPU and RAM/RAM Capacity are at issue.

Hooking up an eGPU with an RX590 will do about 1000% more than a TB3 drive on that iMac, Lol.

Even Free Resolve on Mac supports GPU Decode so there is limited utility (and arguable gains, especially given the weak CPU in that machine) in transcoding that footage to a heavier - CPU-bound - CODEC. You're just wasting disk space. You're better off just creating 1/2 Res H.264 Proxies at a low bitrate, instead.

I was thinking about caching to the SSD in a format that need more bandwidth, but can be used right away for a ProRes master.
A cache on a spinner doesn't help that much, it's all about access times. And then, he could use that master on the other machine for transcoding, while working on with the iMac. As we all know, Resolve doesn't encode in the background. Remember, he was mainly complaining about the time in Deliver.

You are right that an eGPU would be much more efficient, but does it really make sense to invest into that in the current market situation? They are on their way out anyway. And then, we still don't know his codecs, so we can't tell if his Intel GPU does handle them or not. If it does, the eGPU will only help with demanding effects.

According to Wikichip it supports most of them, but in my experience Resolve is faster if you don't need to encode while rendering with an integrated GPU:

Uli Plank wrote:Transcode to H.264 with Handbrake for final delivery and compare which one is faster for this step.

How do I go about this one?

Yes, the eGPU will be efficient but not affordable. We will not be doing this in the long run and hope to come back to regular worship service soon. We only do these video edits in the meantime while we are doing Livestreams. So we're grateful that we found Davinci Resolve because it's free and found it more user-friendly compare to Adobe Premiere and Final Cut. So I guess we're finding ways(cheaper) to get by until we can meet in person for our worship services.

That's what I assumed. Set your render cache to ProRes 422 HQ:

Make sure that your export in Deliver is set to the same format and under "Advanced Settings" activate "Use render cached images".

Get Handbrake for the Mac (free), drag your master file into it and choose something like this:

Handbrake is available for Windows too.

EddieTed wrote:...Editing is better in Mac but when it comes to delivery it takes as much time as the PC...

The thread title says "Mac slower than PC", but your description says "takes as much time as the PC". Can you elaborate on whether the Mac exports slower than the PC or roughly equal to the PC? If slower, how much slower?

As already stated, your Mac's CPU has half the cores of your PC. The PC's i7 CPU is hyperthreaded, whereas the Mac's i5 is not. So the PC's CPU actually has 8 logical cores vs the Mac's 2 logical cores. Even though hyperthreading does not add linear performance, it does help some. It might be expected a Mac with 1/4 the logical cores might be be slower on some things.

I don't know if Resolve's smart render cache is leveraged for export, but you could try enabling that. It's under Playback>Render Cache>Smart.