Let me share my perspective. I work with various video formats and have a 2009 Mac Pro (see sig.).
Let's first admit that if you can take your source footage, regardless of resolution and fidelity, and just start to work on it right away at native resolution—there are no real downsides: no extra steps and no loss of information at the time of working with the material. If you already have that kind of setup—fine!
That said, I honestly think building a new rig to at all cost be able to playback that 8K (or even 4K) footage in realtime is a brain fart.
My setup is two 2560x1440 monitors. This means that I'm grading on the GUI monitor, which is a no-no for a color suite, but good enough for non color critical commercial jobs. In the next few weeks I'll hook up my BMD Decklink Mini Monitor 4K card and do color managed monitoring on a third monitor, most likely a 55" LG OLED. Sitting very close to a 55" screen would shift my workflow to 4K, but only at that point (and I certainly have no 8K ambitions). OLEDs have been known to calibrate pretty well for SDR content, but this is still almost considered "cheaping out".
While there are some high end commercial color suites that use a similar setup (monitoring on a calibrated OLED for SDR), it is much, much, much more common to use a proper grading monitor in HD from let's say Flanders. Even in HD they are already eye wateringly expensive, and I believe the actual quality is still better in the HD panels compared to higher resolutions. Final quality control at target resolution is done later in a rented theatre.
I'm guessing at this point most hobbyists, even with ambitions, realise that this is actually one level above what they have in mind.
Performance:
Some of my 4K material is .MJPEG or ProRes. I don't need to do anything here. My computer can handle this in a 4K timeline. Some of my material is Mavic 2 Pro 10-bit HEVC. This is tougher. Here I transcode to HD ProRes LT and edit and do initial color with that. Final color and export is done in 4K/UHD. I've routinely worked in 2K/HD so far on my monitors and I see zero need to step that up before going to that OLED setup.
I see lots of users on Reduser.net that ask questions about building a PC for 8K and so on. To me this is much more about a personal giggling curiosity than sound workflow thinking. "I have an 8K camera! I want to see it all the time! I want to, I waaant toooo!!!!"
Computer components responsibility in video work:
The CPU decompresses compressed codecs. RED raw needs lots of CPU at higher resolutions for real time high quality debeyer. H.264 and H.265 need CPU power to decompress in real time. A proper intermediate codec like ProRes 422 or Cineform uses very little CPU power.
The graphics card(s) does the computational work for video effects and color. Things like noise reduction and stabilisation can be accelerated here too. In a software like Davinci Resolve, if you're using ProRes (and you're not limited by CPU), adding a second graphics card might effectively double your playback fps.
If your HDD speed becomes critical or not depends upon: how many simultaneous video streams you need to read/write and your codec. Uncompressed video is demanding (some apps cache data like this). RED raw is compressed and not very hard in terms of data rate (more so on CPU at high quality and resolution). With ProRes 422 HQ I can do 3+ streams of 2K or just about one stream of UHD from a Western Digital Passport 2.5" USB drive. With Cinema DNG RAW I can do two streams of UHD on my RAIDed (x2) SSD volume (SATA limited to around 500 MB/s).
RAM. Hugely misunderstood from what I read online. Doesn't add any speed, but too little can slow you down. A DaVinci Workstations is fine with 16GB for most situations. Since most users with workstations today use at least 32 GB and often more, this becomes a non issue. My 2009 computer has 48 GB and I never had issues in video or 3D. I realise that some workflows can use 100+ GB or RAM to read in textures or assets for single files. But that isn't useful information, in a more general discussion.
LED lights. Annoying, distracting, ugly. Zero performance benefit. But you already knew this. =)
[doublepost=1551008817][/doublepost]Classic: I went on such a rant that I didn't write what I actually intended: a cheap iMac 5K with an i7 from late 2014 or better still performs pretty well from a CPU standpoint. You'd want 4GB graphics memory or more. Only with the 2015 iMac did the display get P3 wide gamut.
I wouldn't invest in an old Mac Pro today. I'd wait for the iMac refresh, likely to get Mini LED displays and updated components. In the Mac world, a carefully configured iMac is the best 'jack of all trades' for most users, including creatives. I'm hoping for a bit more exciting BTO options in the next get iMacs: more cores with better cooling. OK graphics, notably better display, which is arguably already good, with some HDR capability.
Fingers crossed for a consumer friendly Mac Pro, but I fear it will be expensive.
