M395 vs the M395X

Discussion in 'iMac' started by iMas70, Mar 4, 2017.

  1. iMas70 macrumors 65816

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    #1
    I'm configuring the 27" iMac I'd like to purchase this month and am wondering if I will see a noticeable difference if I go with the M395X over the M395 graphics processor. Most of it's work will be for editing 4K drone videos.

    Specs that I'm looking at are -
    • 4.0GHz quad-core Intel Core i7, Turbo Boost up to 4.2GHz
    • 8GB 1867MHz DDR3 SDRAM - two 4GB - I'll upgrade this to 16 or 32GB myself
    • 2TB Fusion Drive
    • AMD Radeon R9 M395 with 2GB video memory
     
  2. xsmi123 macrumors regular

    xsmi123

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    #2
    I have the same configuration WITH 16GB of ram. I haven't run into anything that it hasn't been able to handle. 4K video editing has been fine.
     
  3. givemeanapple macrumors Demi-God

    givemeanapple

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    #3
    There are no speed differences between those cards. Source: I tried them both.
     
  4. John marts macrumors member

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    #4
    How much better is it than the base M380? We just picked up the base 27'' with the 512 SSD. I noticed a bit of lag editing 2.7k video on FCPX, but only when I was editing extra effects.
     
  5. jerwin macrumors 68000

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    #5
    http://barefeats.com/imac5k15.html

    The 395x machine had an i7, though. That could account for most, if not all of the 395/ 395x difference
    The 380 is well behind. Half the speed of a m395x.

    The m390 is closer to the m395 than it is to the m380.

    The problem, of course, lies in the fact that even the m395x is far from the state of the art. A lot of money spent to get something halfway decent, and a lot of money spent to avoid even worse cards.
     
  6. Trebuin macrumors 65816

    Trebuin

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    #6
  7. Zwopple macrumors regular

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    #7
    Not entirely true, GPU's are very important for all sorts of workloads. OpenCL is taken advantage of in macOS quite a lot for the video intensive stuff and Adobe's suite does make good use of the GPU's these days for all sorts of things.

    Video Memory is mostly important for gaming though, or 3D work.
     
  8. joema2 macrumors 65816

    joema2

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    #8
    I edit a lot of 4k drone video using FCPX on a top-spec 2015 iMac. It generally works well but H264 4k is difficult to edit smoothly on almost any computer and software. It is 4x the data of 1080p but our computers are not 4x faster. Both Premiere CC and FCPX support proxy mode, where they generate lower-res files (which is still HD) and for final render/export the full resolution is available. FCPX is fast enough to edit a single stream of H264 4k without proxy but you definitely need proxy for multicam. Premiere is not as fast and does not use Quick Sync so IMO you need proxy for almost any H264 4k editing using Premiere on a Mac.

    Re M395 vs M395X, we discussed this extensively in this thread, including running a bunch of benchmarks. In general H264 editing itself is more CPU-limited than GPU-limited. A faster GPU helps on effects but not all effects use the GPU and the difference from M395 to M395X (while useful) is not dramatic in many cases:

    Benchmarks: https://forums.macrumors.com/threads/m380-m390-m395-m395x-thread.1928278/page-15#post-22210423

    Thread: https://forums.macrumors.com/threads/m380-m390-m395-m395x-thread.1928278/
     
  9. cynics macrumors G4

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    #9
    What software are you going to be using for editing your drone videos?
     
  10. joema2 macrumors 65816

    joema2

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    #10
    Trebuin is correct for the cases he mentioned -- most video encoding and pure editing are CPU-limited not GPU-limited. Anyone can see this themselves by simply doing basic editing operations, rendering and exporting using either FCPX or Premiere CC. Frequently every CPU core will be almost pegged -- because those operations cannot be greatly accelerated by the GPU.

    Outside of pure editing, rendering, encoding and decoding -- in those cases the GPU can help. Since most videos use effects, if those effects can be GPU accelerated, then a faster GPU will help.

    In certain common cases such as using Neat Video noise reduction, the GPU can only help to a limited extent. In that plugin you can select either CPU or GPU rendering (or both) and how many CPU cores to use. The GPU helps but it's not 5x faster than just CPU rendering.

    Another case is generating proxy files. Now that H264 4k is very common, we frequently need to generate proxy files for better editing performance. This is time consuming and I wish it could be GPU accelerated but it's not possible.
     
  11. jerwin, Mar 5, 2017
    Last edited: Mar 5, 2017

    jerwin macrumors 68000

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    #11
    Adobe's Mercury Engine is apparently sensitive to VRAM, with 4K and 5K demanding more.

    https://www.studio1productions.com/blog/?p=302
     
  12. iMas70 thread starter macrumors 65816

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    #12
    I've tried a few programs. I think I'll mostly be using Adobe Premiere Pro.
     
  13. nambuccaheadsau macrumors 65816

    nambuccaheadsau

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    #13
    My suggestion would be to go with what you really want as this machine is going to be lasting you say some five years or so. Also you mentioned the 512GB SSD. Why not consider pure Flash Storage which is faster than an SSD and is available up to 1TB?
     
  14. iMas70 thread starter macrumors 65816

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    #14
    One of the other members here just got an iMach with the 512 GB SSD. I'll be storing a lot of videos so I'll probably go with the 2TB Fusion drive. I'd like this machine to be good for at least 4-5 years so I'd like to spec it right and then not pay attention to whatever Apple introduces sometime this year.
     
  15. Trebuin macrumors 65816

    Trebuin

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    #15
    GPU: Honestly, if you don't play games, then I'd go with the 395 to keep the temps down a little. I've used a video encoder that used the GPU before and it only used about 10% of it so you just won't get much benefit worth the cost. 390 would probably be enough to drive what you're doing as far as the screen goes. Next graphics cards aren't going to help you...you'd go from using 10% to using 5%.

    CPU: you already know to dump your $ in here. This CPU bump will likely give you only up to 10-15% boost. Check the benchmarks if you want to know exactly what to see. I think the 7700K is what's replacing the current chip, which is 6700k if memory serves me right..

    Drive: If you don't want to install a drive yourself, get the apple SSD, not the fusion drive. Encoding large videos does benefit from a faster drive, especially on 2-pass encodes. The hard drive is really the bottleneck of most machines. I wouldn't go large, but just get enough for your apps and OS to live plus some workspace. 512GB would be fine here. If you do install your own drive, know this: Apple's SSDs use a double bandwidth pipe and experiences a doubling of performance, but at a higher price. That's the SSD part of the Fusion drive or the SSD that you buy. If you install a standard SSD, it connects to the front SATA port and regardless will not be able to go near as fast as Apple's SSD. That being said, you likely won't need that speed.

    Memory: buy aftermarket.

    Overkill: get the mac pro.
     
  16. Zwopple macrumors regular

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    #16
    Does the 395X actually run cooler? I don't see how it would given it's the same architecture just running at a higher clock speed. Maybe because it'd get work done faster and be able to "idle" more?
     
  17. joema2 macrumors 65816

    joema2

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    #17
    I don't agree with this. Hard drive performance is rarely a bottleneck for H264 encoding and decoding. Anyone can see this for themselves -- just watch CPU core activity with Activity Monitor or iStat Menus while exporting an H264 video. All CPU cores will be high, which means it's not waiting on the hard drive.

    That said, you can't put much 4k H264 video on a 512GB boot drive, so the faster speed (even if needed) wouldn't help much because the content won't fit. This limitation often causes people to buy a cheap, slow bus-powered USB external hard drive which is far slower than Fusion Drive. But whether SSD or Fusion Drive he will soon require external storage.

    I have both 1TB SSD and 3TB Fusion Drive iMac 27s and I don't see much performance difference in video editing when the content is on a fast external drive.

    Since he's using Premiere he will likely have to transcode to proxy all 4k H264 content to get good performance -- even for a single camera. This will take additional disk space for the proxy files. How much space depends on the proxy resolution chosen, but as a very rough rule of thumb roughly double the storage. So if his camera video is 100GB, he'll need about 200GB of space.
     
  18. cynics macrumors G4

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    #18
    With Adobe Premiere Pro and 4k editing I would go for the m395x. Adobe will leverage the GPU via OpenCL (so the better the GPU the better the performance) and the extra VRAM.

    The difference in performance? Not sure exactly. With FCPX the difference is there but in some cases you need to hold a magnifying glass over it to see it. However FCPX compliments Apples hardware very well so the differences maybe more pronounced with Adobe.

    Have you consider FCPX btw? Just curious everyone prefers something different but with a Mac I find it to compliment the hardware and OS very well.
     
  19. Trebuin, Mar 7, 2017
    Last edited: Mar 7, 2017

    Trebuin macrumors 65816

    Trebuin

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    #19
    395, not 395x runs cooler
    --- Post Merged, Mar 7, 2017 ---
    If you're doing a single stream encode or using software that loads the entire dataset into memory, then yes, most hard drives will no impact. If you're running an encode that's multi-pass or using encoding software that reads the original data forwards & backwards to compress it, then you'll experience disk thrashing...which should be enough said. SSDs also help with paging which hopefully won't be an issue in the first place, & with loading of every app & OS. That being said, I don't keep the final products on a SSD.

    The only time I sided with a hard drive for everything was when I moved every file to the outer portion of the drive's plates to read at the fastest rate. That year, I was able to beat performance on up to a second generation SSD. It was between myself & a friend of min, Les, who owns thessdreview. I have over a decade of experience with both encoding, writing encoding software & with hard drive performance.

    The only thing I will back you up on, the bottleneck with go between the CPU & the HD depending on in particular configurations. SSD will give you maybe a 5% boost. If you have an older CPU, that will bottleneck out. If you have newer one, the disk will slow things down at times, especially if it is the OS disk & file to 90% of capacity. try encoding a video off a USB 2.0 drive to simulate the inner portion of a hard drive accompanied with disk thrashing & you'll see what I'm talking about.
     
  20. cynics macrumors G4

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    #20
    I think kept within the context of this thread his post is accurate no? And they did say "rarely".

    We are talking Adobe Premiere Pro with the absolute best hardware being a 6700K and m395x. Admittedly I'm not familiar with Adobe Premiere Pro but I find it unlikely it could max out a 7200RPM HDD for the purpose of encoding.

    I believe you know what you are talking about so out of curiosity what would be a piece of software that could read forward and backwards for encoding? And in general what CPU's could process that data fast enough to bottleneck at a 7200rpm HDD? I'm assuming you mean when its thrashing correct?

    For me storage speed isn't even considered, software encoding via handbrake on a very slow preset with an i5-4760 isn't that demanding for an HDD (2-3 MB/s watching activity monitor right now). But even with a 6700K I wouldn't be setting the world on fire with my specific task.
     
  21. Trebuin macrumors 65816

    Trebuin

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    #21
    I agree with your point on the rarely use.

    If you're wanting to dig more into the encoding, I was more into VC-1 & I've seen avi's with x264 encoded in a way where it does the same thing. To put it simple, the encoder is set to look at a chunk of video for a period of time breaking it by either keyframes or some other parameter the encoder is designed to use. Like you, I don't know how Adobe runs their encoder & I've digressed to handbrake due to get a higher encode. Essentially, the encoder will decide how it will handle that chuck of data. When it uses scene changes, it can customize pixilation to have lower color gradient over a part of an image that is a low gradient smooth area, such as dark spots or walls. If the other half of that image has rain, crank the data on that side of the image, rather than keeping the image a single consistence. With that in mind, consider the dimension of time...look forward to detect how long that technique will work, then roll back to do the actual encoding. If you download a video with only parts of the stream, you can have see how this can actually be a problem if you get 2% of a video, with 100% of it being streamed from the start, but not playing because the data isn't complete. You can do the same thing on another video & notice that it is working just fine. That's because some of the data for that first stream is saved beyond that 2% & not stored in chronological order as a classic movie reel would work.

    If you don't bottle neck a encode on the CPU, using some of the lowest level profiles to keep videos compatible for a PSP in my case with a I7-2860QM, or simply use an encoder that doesn't compress well & reads a fragmented file, you'll see the CPU use around 50-100% while the hard drive is clicking away. I still do encodes on an older 5400RPM internal secondary drive & they do take quite a bit longer.

    On the GPU side, I used an older version of TMPGENC which used nVidia's Physics engine, but I found it used almost no amount of the GPU & the encode was extremely slow because I selected the features that would use the engine in the first place, something I could live without. I hope I didn't lose you too much on the details on encoding. There's some really good reads out there on different techniques of encoding...but I'm doing pretty much what you probably do now with handbrake.
     
  22. iMas70 thread starter macrumors 65816

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    #22
    Trebuin - You suggested a small HD. Are you thinking I should go with an external drive for storage?
     
  23. joema2 macrumors 65816

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    #23
    The OP was asking specifically about 4k drone video, Premiere Pro, and how SSD vs 2TB Fusion Drive might effect editing or rendering performance. He was not asking about performance using 3rd party transcoding tools, nor was he asking about using a USB 2.0 external drive. Nobody in their right mind would edit or export/import 4k video from a USB 2.0 drive.

    I just did several multi-pass encoding tests using H264 4k video from a DJI Phantom 4 on both Premiere and FCPX, using both a portable USB 3 bus-powered hard drive and the local SSD drive of my 2015 iMac 27.

    Results:

    (1) No difference in Premiere multi-pass H264 encoding/export performance whether media was on a 100 MB/sec portable USB 3 drive or an 1800 MB/sec SSD.

    (2) Total data volume and I/O requests read/written for multi-pass encoding of an H264 4k file is very low, averaging about 1.4 MB/sec reads and 2.2 MB/sec writes over the encoding period. This is well within the performance capability of a USB 3.0 external drive or a Fusion Drive.

    (3) Premiere CC 2017 H264 export is highly CPU-bound, with all cores at 100%. This alone tells us it's not I/O-limited in the slightest, otherwise it would be waiting on I/O, and CPU would be lower. However Activity Monitor gives the actual I/O performance numbers which confirms this.

    I'm not particularly advocating he get the 2TB Fusion Drive iMac, only that it won't make much performance vs SSD difference for a few small 4k drone videos. However if he does much video work he will rapidly need an external drive, so in that case why not get the SSD iMac? He will also need a backup drive so he'll actually need two external drives.

    Even though pure exporting to H264 does not require a fast drive, other editing tasks may. This includes editing multicam 4k from lower-compression codecs such as ProRes or DNxHD. So whatever external drive he gets, it should not be slow.

    Although he was interested in Premiere I tested the same clip in FCPX and the export numbers are below:

    Material: 1 min 30 sec 4k H264 video from DJI Phantom 4 drone, size=681 MB, bit rate = 60 mbps

    Premiere CC 2017 multi-pass export to 30 mbps 4k H264: 7 min 19 sec
    Premiere CC 2017 single-pass export to 30 mbps 4k H264: 3 min 41 sec
    Premiere CC 2017 export to DNxHD MXF: 3 min 1 sec

    FCPX 10.3.2 multi-pass export to 30 mbps 4k H264: 2 min 11 sec
    FCPX 10.3.2 single-pass export to 30 mbps 4k H264: 1 min 7 sec
    FCPX 10.3.2 export to ProRes 422: 1 min 3 sec
     
  24. Trebuin macrumors 65816

    Trebuin

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    #24
    thinking back on the drive design, if the drive is large enough, the speeds should be high enough today to be no impact. USB3.0 won't help to simulate the inner portion of a hard drive or fragmentation. I brought up USB 2.0 because that allows some maxed drive simulation to show what I'm talking about. USB 2.0 might be good enough to simulate working with fragmentation, but is too slow to compare to a large 7200 hard drive even on the inside of the drive. What joema2 is pointing out is good info. The 100MB/s description on a hard drive is extremely relative because a spinning hard drive's speed varies by approximatly 100%. Google "Hard drive HD tune" & look at the first image to see what I'm talking about.

    Even at the low end, say 80MBps, you're not going to run into issues provided your drive is not fragmented. If you're not going to use up even 3/4 of a 2TB drive, you're good sticking with that. You shouldn't run into a non-sequential read issue. My other example is on older generation hard drives where you could easily see some non-sequential read issues.

    USB 3.0 & TB both also give you a great deal of flexibility. SSD shouldn't have any impact on today's encoding. & SSD is really only going to help with program loading time & boot time, unless you have a decent SSD portion of a fusion drive. You can read in other threads about that.
    --- Post Merged, Mar 8, 2017 ---
    That's what I would do, but I have over a TB of maps loaded on my computer. If you don't use that much space, you might only create a backup of your drive externally, or you can use an online service. I do both considering I live downstream from the Oroville Dam that has two giant holes in the side of the mountain.

    The 2-3TB fusion drives have enough flash space to store your OS & several programs & are cost efficient. 1TB, not so much space. SSDs probably only will benefit people with a lot of games & for people who run windows in bootcamp as well.

    Basically, we're pointing you towards the fusion drives.
     
  25. iMas70 thread starter macrumors 65816

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    #25
    I just took a look at the size of some of my videos. They range from 450-800MB. Photos are 7-8MB. The drone will be getting a lot of use after the weather warms up.
     

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