When running Apple Compressor 4.1 as a bench-mark, the new Mac Pro is faster for some compression tasks and significantly slower for others when compared to a recent model iMac. If video compression is your primary use for a new computer, you may be better off buying a top of the line iMac.
I was totally surprised by these findings. Until we start to see applications optimized to take advantage of the power of the Mac Pro, if video compression is your key task, a high-end iMac is your best choice.
Our own tests show only H.264 hardware compression to be slower on the new "tubes". I suspect there is something that needs to be tweaked to allow the new tubes to do hardware H.264 compression. But everything else on the new tubes are so much faster, especially with 4K, I'd not let compressing H.264 files hold me back. Besides, how many of us buy a Mac to do only video compression?
My understanding is that the new single-pass H.264 hardware codec is using
Intel's Quick Sync
– their brand name for such things in the Core processors.
The issue is that Quick Sync isn't enabled in Xeon range CPUs. If I'm reading the information correctly, it's a specific hardware module that's vastly improved in Haswell-generation Core i5s and i7s, but I'm not clear if the module is even present in Xeons. It's seen as a consumer technology, not a professional one.
This implies that the Mac Pro tube won't see comparable encoding speeds to iMac. At least, not via this route: it's possible H.264 encode will be implemented on the GPUs at some point, which I'd guess would yield comparable results.
...but it's entirely possible that the tube will always lag for this specific task.
...The issue is that Quick Sync isn't...present in Xeons. It's seen as a consumer technology, not a professional one.
This implies that the Mac Pro tube won't see comparable encoding speeds to iMac. At least, not via this route: it's possible H.264 encode will be implemented on the GPUs at some point, which I'd guess would yield comparable results....
Quick Sync is apparently implemented in the on-chip GPU. That doesn't mean it's a GPU task per se, rather the on-chip GPU is where the Quick Sync functional elements were architecturally located. The Ivy Bridge, Haswell, etc Core-branded CPUs have an on-chip GPU, even if your computer has a external discrete GPU: www.intel.com/content/www/us/en/architec...c-video-general.html
Xeon does not have an on-chip GPU -- thus no Quick Sync -- apparently because it was viewed a poor use of on-chip resources for the server and high-end workstation market segment. Even at current fabrication technology, the low-end on-chip HD Graphics 2500 GPU takes about 400 million transistors (out of 1.4 billion available in Haswell and lower-end Xeons): www.techpowerup.com/gpudb/1250/hd-graphics-2500.html
From this standpoint lower-end Xeons would be wasting nearly 30% of their transistor budget on a GPU they'd never use, since those envisioned platforms always have dedicated discrete GPUs. Xeon urgently needs those transistors for workstation-class functions like larger caches, ERC memory, etc.
Intel probably made those decisions several years ago. They likely didn't envision the current ironic situation with consumer-class CPUs with Quick Sync out-performing workstation-class Xeons in narrow transcoding tasks.
Quick Sync is essentially an on-chip ASIC, a hardware transcoder for single-pass H.264 and MPEG-2. It's fast but that's all it can do -- it's single purpose. By contrast GPU APIs and resources are more flexible and can accelerate a broader range of tasks, but cannot currently equal Quick Sync on H.264/MPEG-2 transcoding, no matter how fast the GPU. Intel discusses this on page 10 of their IDF13 white paper "Utilizing Intel Quick Sync Video for High Density Video Transcoding in Communications Servers" (78 MB .pdf):
When the "no Quick Sync for Xeon" decision was made, Intel may have felt one or more of the following:
(1) That functions accelerated by a discrete GPU on Xeon platforms might eventually approach Quick Sync performance for transcoding (that has not yet happened).
(2) They just couldn't afford the transistor budget to put Quick Sync on Xeon at then-current fabrication technology
(3) As fabrication technology advances, eventually putting Quick Sync on Xeon will be possible, thus the current Xeon Quick Sync deficiency is an acceptable temporary situation. The upcoming 15-core Xeon E7 v2 has nearly five billion transistors, so theoretically could better afford Quick Sync (although I haven't seen this planned).
(4) Workstation-class machines typically have longer service lives, so performance factors over that period are more important. When we switch to H.265, it is unclear if current Quick Sync will work with that. You could suddenly find yourself without Quick Sync acceleration. By contrast Xeon-class workstations using GPU-accelerated (not Quick Sync) transcoding would remain fast.
Quick Sync is very fast for the few tasks it handles. However if you watch thread activity while doing video editing or many other demanding tasks, they are often CPU-bound, and GPU is increasingly used. Despite the irritating Quick Sync deficiency (which isn't Apple's fault), I'd rather have an 8 or 12-core nMP for heavy video editing or similar tasks. The faster GPU and core count are broadly useful tools which help many things, whereas Quick Sync is a "one trick pony", albeit a currently useful one.
If it comes down to 4K authoring, then go New Mac Pro.
If no and you want to spend half of what It will cost for the New Mac Pro go buy an IMac.
Well, therein lies the problem. I'm not shooting or editing 4K, but who knows two years from now, or even a year from now.
I have one job this year that the client says they want in 4K because it's for a large screen on an exhibition stand. I know I can edit in proxy, but if I get asked too many more times then I'll wish I had the new MacPro for sure.
But my gosh before you say no to the full spec IMac try one.
Mine has 32 GB Ram with a cheap Raid 0, USB3.
USB3 would be my plan too, at least initially. I have a USB3 raid running off our MacMini and sometimes that renders faster than my MacPro 3,1 !!! Arrgghh! It's especially fast for After Effects for some reason too. Hmmm....
If it's a New Mac Pro then you are more likely to need to buy a Thunderbolt Promise Raid or the TB G-Drive Raid.
Out of interest, why would a USB3 raid work fine on an iMac and not the new MacPro (assuming not editing 4K) ? It seems to me if it works for one it should work for the other for now at least.
...If it's a New Mac Pro then you are more likely to need to buy a Thunderbolt Promise Raid or the TB G-Drive Raid...So trust me, sit down, plan and budget carefully...If IMac get the biggest SSD possible.
The "budget carefully" advice is good. You have to look beyond the computer -- to the overall system budget and performance at a given price point.
E.g, spending on a new Mac Pro could leave no money to buy a Promise Raid. I have seen countless people spend all their money on a given system, run out of storage, then hook up a little bus-powered USB hard drive because that's all they can afford. It doesn't make sense.
Re SSD in the iMac -- it is very fast but 1TB is currently $650 more than a 3TB Fusion Drive, and $800 more than 256GB SSD. If the video files won't fit on 1TB SSD (actually less, on the available space left over), and if an external RAID array is needed anyway, there's a good argument to get a smaller SSD and put the files on RAID.
In our documentary work the shooting ratio is high, so there's no way it would fit on 1TB. Other genres will fit -- if so, by all means get SSD. It is extremely fast. But the utility of SSD depends on whether your software and workflow are predominantly GPU-bound, CPU-bound or I/O-bound. If GPU or CPU-bound, even infinitely fast I/O won't improve things. A chain is only as strong as the weakest link.
I have a 2013 iMac with 3TB Fusion and an 8TB Pegasus R4 in RAID 5, which I use heavily on FCP X. In general I'm happy with it -- it is rarely I/O-bound, regardless of where I put the media and library files.
It is often CPU-bound. So far FCP X does not harness the GPU for accelerated effects to the degree Premiere Pro does. X is very good at background rendering, but if you watch the cores in iStat, they are frequently pegged. In this scenario, the additional cores of a nMP would be useful.
X does use GPU a lot -- you can see that in iStat. For those phases, the nMP's faster GPU would benefit. OTOH we do lots of exports for evaluation, and the iMac's fast Quick Sync encoding is handy. I have tested export perf. vs Premiere Pro CS6 on similar hardware, and X can be 4x or 5x faster.
But overall people shouldn't think they must get a nMP for video editing, outside of specialized situations. A maxed-out iMac is very capable, and leaves money available for external RAID systems and more disks to back up those.
Previous Quote "Out of interest, why would a USB3 raid work fine on an iMac and not the new MacPro (assuming not editing 4K) ? It seems to me if it works for one it should work for the other for now at least."
While USB 3 would function perfectly well on a New Mac Pro.
The natural inclination would be to move to Thunderbolt 2 to take full advantage of the robust architecture of the New Mac Pro. Remember The IMac only have Thunderbolt not Thunderbolt 2 (twice as fast).
The throughput of the media is key to a fast edit for 4K.
The internal SSD is really meant to be for only Application and cache use.
Maybe common media files that reoccur often could be store locally.
I am just future proofing by saying buy a large SSD.
In no way do I mean that media should be anywhere but the Raid or some other fast external device.
Just nice 4 years down the road to know you have a 500 GB SSD for all the apps you might be running.
It's hard to get back into the New IMacs to upgrade, but not impossible.
I think a 3TB fusion drive makes sense in the iMac 27" simply because it gives some room to grow without being quite so horrendously expensive.
In terms of the external RAID, of course TB2 would be the best options, immediate funds permitting, but I'm also hoping that the next iMac update will have TB2 as well.
That being said, until 4K becomes the norm, a slower RAID system (USB3) should prove perfectly adequate, then update to TB2 later when 4K is knocking on the door every day.
Right now we have around 18TB online but it's all running at slower speeds than TB2. Is it a problem? Not really. My big bottle neck right now is the ageing combination of the CPU/GPU/RAM Speed within the MacPro 3,1. That's what needs updating next. The RAID updates can happen some months afterwards.
Our storage problem is not so much of a problem today, it's which CPU/GPU box makes most sense, not just today but in 2, 3 4 or more years time. If the iMac had more TB ports and an HDMI port then the iMac would be a shoe-in. Lack of ports does worry me.