How much memory is needed to edit 4K video?

[Scott2014]

Hello,
I am considering buying a DSLR camera to shoot 4K video. I would like to be able to edit this 4K video footage on my iMac (I use Final Cut Pro).

My three questions are:
1. About how much memory is needed for an iMac to smoothly process 4K video footage?
2. How do I check how much memory is already in my iMac?
3. What is the easiest way to efficiently add more memory to an iMac?

Note: These days External hard drives are continuously getting less and less expensive. Therefore I am not concerned about hard drive space. I am only concerned about memory processing.

Thank you.

 

[yjchua95]

Hello,
I am considering buying a DSLR camera to shoot 4K video. I would like to be able to edit this 4K video footage on my iMac (I use Final Cut Pro).

My three questions are:
1. About how much memory is needed for an iMac to smoothly process 4K video footage?
2. How do I check how much memory is already in my iMac?
3. What is the easiest way to efficiently add more memory to an iMac?

Note: These days External hard drives are continuously getting less and less expensive. Therefore I am not concerned about hard drive space. I am only concerned about memory processing.

Thank you.

You need an i7 that's for sure to make use of hyper threading.

I suggest a minimum of 16GB of RAM. I shoot with a EOS-1Dc in 4K and use a 27" with i7 and 32GB of RAM, plus a GTX780M to speed up rendering times.

The easiest way to add RAM to the iMac is buy from Kingston, Crucial or some other manufacturer and replace them yourself. You can only do this on the 27", not the 21.5".

To check your RAM in your iMac, go to  → About This Mac.

 

[Scott2014]

Thank you. I checked, and I have:

-iMac 7.1
-1GB memory
-2.4Ghz Processor Speed

Does it sound like this computer is just hopeless for editing 4K video? Or does it sound like I could add memory and get it work?

If the latter, roughly how much money do you think I’d need to spend on adding the right amount of memory?

Again, thanks so much.

 

[p3ntyne]

Thank you. I checked, and I have:

-iMac 7.1
-1GB memory
-2.4Ghz Processor Speed

Does it sound like this computer is just hopeless for editing 4K video? Or does it sound like I could add memory and get it work?

If the latter, roughly how much money do you think I’d need to spend on adding the right amount of memory?

Again, thanks so much.

Hmmm.... You should probably invest in a new computer. You only have an Core 2 Duo (kinda hopeless for video) and your computer can only handle a max of 6 Gb's RAM. From Crucial, for 5 Gb's (the stock 1 Gb + Crucial 4 Gb's) will cost $105.99 and 6 Gb's (Crucial 4 Gb's + Crucial 2 Gb's) will cost $141.98.

IMO, you should sell the one you have and pick up a refurbished model from 2012.

Hope this helped.

 

[yjchua95]

Thank you. I checked, and I have:

-iMac 7.1
-1GB memory
-2.4Ghz Processor Speed

Does it sound like this computer is just hopeless for editing 4K video? Or does it sound like I could add memory and get it work?

If the latter, roughly how much money do you think I’d need to spend on adding the right amount of memory?

Again, thanks so much.

It's hopeless all right. You need at least 16GB of RAM (your current system can only support 6.0 at the max).

And you need a processor in the 3+ GHz range that's capable of multithreading. That means an i7. The i5 cannot multithread.

If you can find a refurb 2012 27" with 2GB GTX680MX GPU, go for it. Better still, go for a refurb/brand new 2013 27" iMac with i7 and GTX780M GPU. You can always upgrade RAM yourself on the 27" but not on the 21.5".

Considering that you're doing 4K video, you'll need all the speed you can squeeze out of your hard drive. Which means Fusion is out of the option. You've to go for a pure SSD setup.

 

[p3ntyne]

It's hopeless all right. You need at least 16GB of RAM (your current system can only support 6.0 at the max).

And you need a processor in the 3+ GHz range that's capable of multithreading. That means an i7. The i5 cannot multithread.

If you can find a refurb 2012 27" with 2GB GTX680MX GPU, go for it. Better still, go for a refurb/brand new 2013 27" iMac with i7 and GTX780M GPU. You can always upgrade RAM yourself on the 27" but not on the 21.5".

Considering that you're doing 4K video, you'll need all the speed you can squeeze out of your hard drive. Which means Fusion is out of the option. You've to go for a pure SSD setup.

Why wouldn't a fusion work well? If it were my machine, I would get the 3 Tb fusion as an uncompressed 2 hour 4K video is ~500 Gb's. You would want to keep at least 5 hours before needing to move it externally...

 

[yjchua95]

Why wouldn't a fusion work well? If it were my machine, I would get the 3 Tb fusion as an uncompressed 2 hour 4K video is ~500 Gb's. You would want to keep at least 5 hours before needing to move it externally...

Video is I/O intensive.

The Fusion drive only has a 128GB SSD. Which means most of the video, or the entirety of the video would rest in the HDD section, which is slow.

A regular 7200rpm HDD operates at around 150MB/s on a 27" iMac. Way too slow for even 2K video.

A Fusion setup would perform at around 500MB/s read and 350MB/s write.

A pure 256GB SSD would perform at 710MB/s read and 670MB/s write.

A pure 512GB SSD would perform at 750MB/s read and 710MB/s write.

For 4K, you'd need all the power you can squeeze.

The screenshot I attached is from a 256GB SSD from my 21.5" iMac.

I've also attached a speed test of a 7200rpm 2.5" HDD mounted in a Thunderbolt enclosure. As you can see, the HDD just can't cut it for even 720p video.

 

[thekev]

Thank you. I checked, and I have:

-iMac 7.1
-1GB memory
-2.4Ghz Processor Speed

Does it sound like this computer is just hopeless for editing 4K video? Or does it sound like I could add memory and get it work?

If the latter, roughly how much money do you think I’d need to spend on adding the right amount of memory?

Again, thanks so much.

Memory can be added in sets of 2 x 8GB sodimms on some of the new imac models. Avoid the most recent 21" models, due to lack of ram access. If you need to save money, go refurb 27" rather than 21". You can be conservative and buy one set when you buy such a machine. Your current one is an older one. It maxes at 6GB of ram. It's not likely that you will be happy trying to edit at 4K on the thing. It's also very IO bound. Overall I think you would be miserable on that thing with anything past (maybe) 1080. The old Final Cut Pro is also probably not going to cut it. FCPX is cheap, or you can always look at Premiere.

 

[p3ntyne]

Video is I/O intensive.

The Fusion drive only has a 128GB SSD. Which means most of the video, or the entirety of the video would rest in the HDD section, which is slow.

A regular 7200rpm HDD operates at around 150MB/s on a 27" iMac. Way too slow for even 2K video.

A Fusion setup would perform at around 500MB/s read and 350MB/s write.

A pure 256GB SSD would perform at 710MB/s read and 670MB/s write.

A pure 512GB SSD would perform at 750MB/s read and 710MB/s write.

For 4K, you'd need all the power you can squeeze.

The screenshot I attached is from a 256GB SSD from my 21.5" iMac.

I've also attached a speed test of a 7200rpm 2.5" HDD mounted in a Thunderbolt enclosure. As you can see, the HDD just can't cut it for even 720p video.

Well, I guess a DIY fusion would work then...

Perhaps the 1Tb Hard Drive and a 480 Gb SSD.

 

[thekev]

Well, I guess a DIY fusion would work then...

Perhaps the 1Tb Hard Drive and a 480 Gb SSD.

The OP still couldn't do that on his current machine due to lack of space for a second internal drive. It's a very old imac, which is why he's probably looking at both a new one and different software. I don't know whether FCP 7 even runs properly under Mavericks, which is what he would get with a new machine.

 

[yjchua95]

The OP still couldn't do that on his current machine due to lack of space for a second internal drive. It's a very old imac, which is why he's probably looking at both a new one and different software. I don't know whether FCP 7 even runs properly under Mavericks, which is what he would get with a new machine.

Besides the OP doesn't have enough RAM even if he maxed it out.

He needs at least 16GB of RAM.

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Well, I guess a DIY fusion would work then...

Perhaps the 1Tb Hard Drive and a 480 Gb SSD.

Even if the OP put in an SSD in his current machine, it would still fail in 2K tasks, let alone 4K. His current iMac doesn't support SATA 3. So it'll only operate at perhaps 250-300MB/s, which is insufficient for even 2K.

 

[thekev]

Besides the OP doesn't have enough RAM even if he maxed it out.

He needs at least 16GB of RAM.

That is true. His maxes at 6. Apple officially says 4. The memory controller will recognize up to 6. If he's on a budget, he will have to be careful due to the need to simultaneously update hardware and software that may not work on the updated OS. That's also why I suggested he test 16 first, then go from there. Depending on what he is doing, it may be fine. I get the impression that the camera cost alone has invoked a minor amount of sticker shock, so he's trying to control associated costs (not that I blame him).

 

[joema2]

...And you need a processor in the 3+ GHz range that's capable of multithreading. That means an i7. The i5 cannot multithread.

The i5 does multithreading just fine. Each thread is an asynchronous task which is the finest-grain item managed by the OS scheduler. Each thread can run on a single core, so all multi-core CPUs and all multi-CPU computers are can run concurrent multithreaded work.

Intel i7 and Xeon CPUs have an additional feature called hyperthreading, so that under limited conditions each CPU core can run two threads. However this by itself doesn't make the CPU multi-thread capable - any multi-core CPU is. A hyperthreaded CPU like the i7 may get 10-30% extra benefit on an favorable multithreaded load, but the typical benefit is less. However for 4k video editing, every little bit helps, so the i7 is a good idea.

....Considering that you're doing 4K video, you'll need all the speed you can squeeze out of your hard drive. Which means Fusion is out of the option. You've to go for a pure SSD setup.

You don't need SSD to edit 4k video. 4k cameras like the 1DC record to CF cards, which can only do about 150 megabytes/sec. A Fusion Drive has over 2x that writing rate and 4x that reading rate.

Newer high-efficiency codecs cut this data rate further, at the cost of higher CPU load. It appears that H.265 will allow 4k video using only about 4 megabytes/sec: https://blogs.iis.net/alexzam/archive/2013/01/28/h-265-hevc-ratification-and-4k-video-streaming.aspx

Some edit suites like Premiere Pro can edit in the native capture format, though not optimally. This further reduces the I/O load. If the edit suite requires transcoding to a less compressed format, that decreases the CPU load but increases the I/O load. So part of the decision is what codec and edit suite are planned.

That said, your basic point is correct -- the OP needs a new, high-end machine to effectively edit 4k video. Personally I would get a top-spec iMac with SSD and a thunderbolt RAID array, if not a Mac Pro. However a top-spec iMac with FD would probably work, just not quite as well.

 

[p3ntyne]

The OP still couldn't do that on his current machine due to lack of space for a second internal drive. It's a very old imac, which is why he's probably looking at both a new one and different software. I don't know whether FCP 7 even runs properly under Mavericks, which is what he would get with a new machine.

I was not referring to his current machine.

 

[CH12671]

Instead of spending all of your money on a new machine, why not just use proxy media? Should be able to edit just fine, then output to full resolution.

 

[Scott2014]

The old Final Cut Pro is also probably not going to cut it.

What is your definition of "the old" here?

 

[thekev]

What is your definition of "the old" here?

Typically if someone mentions it as final cut pro, they mean final cut pro 7 rather than FCPX. Given the older hardware I figured you might still be on that, speaking of which there's nothing wrong with older hardware. I just don't think it's up to task for what you want to do now. You could always see how it goes, but I wouldn't invest too much money in aging hardware.

 

[Scott2014]

Hmmm.... You should probably invest in a new computer..

I appreciate your input, and you probably have a smart idea. But I can be stubborn at times, and I just refuse to buy a new computer.

I currently use this iMac to edit 720p video, and it works great… I’d like to update my camera (which dates back to around 2000)... But I just bought this iMac back in 2008. I believe that’s too recent to replace it while it still functions as well as it ever did.

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It's hopeless all right.

If that's the answer, so be it. Thank you.

Now, my next question is:
Can I add memory and make this computer able to efficiently process 1080p video?

 

[CH12671]

Proxy media

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You can do 4K video just fine with what you have. Adding some RAM will help, but you could do it with what you have. Just choose the Proxy media your machine will handle.

 

[p3ntyne]

I appreciate your input, and you probably have a smart idea. But I can be stubborn at times, and I just refuse to buy a new computer.

I currently use this iMac to edit 720p video, and it works great… I’d like to update my camera (which dates back to around 2000)... But I just bought this iMac back in 2008. I believe that’s too recent to replace it while it still functions as well as it ever did.

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If that's the answer, so be it. Thank you.

Now, my next question is:
Can I add memory and make this computer able to efficiently process 1080p video?

You will be (just) be able to with 6 Gb's RAM. Also, an SSD (and HDD to if you want) and a processor upgrade will help make everything a bit more responsive...

 

[joema2]

...I just refuse to buy a new computer...
I currently use this iMac to edit 720p video, and it works great… I’d like to update my camera (which dates back to around 2000)... But I just bought this iMac back in 2008. I believe that’s too recent to replace it while it still functions as well as it ever did...

See attached graph. Note the bit rate increase from 720p to 1080p to 4k. It is gigantic. The vertical axis is x kilobits/sec. I think this is the MPEG-2 encoded rate, by current standards a low level of compression. More sophisticated codecs attempt to lessen the data volume -- at the expense of CPU load. So you have to pay one way or the other -- more CPU or more I/O.

When commercial HD broadcasting began, FOX, ABC and ESPN chose 720p/60, and most other networks choise 1080p/30. There were two reasons:

(1) Fox, etc had significant sports content which was rendered more smoothly at 60 fps.

(2) The 1080p cameras could not do true 1080p because of the increased data volume. They were silently down-sized from 1920x1080 to 1440. Only the networks using 720p/60 were getting the specified resolution. Finally after several years the 1080p networks started delivering true 1080p resolution.

So they were unable to move to full 1080p, despite having cameras and distribution systems costing millions of dollars. Your 2008 iMac may be hard pressed to handle 1080p, and I doubt it can effectively handle 4k.

2008 iMacs had a dual-core Intel Core 2 CPU, at 2.4 to 2.8Ghz. Since then the CPU generations have been Core->Penryn->Nehalem->Westmere->Sandy Bridge->Ivy Bridge->Haswell.

The CPU in your iMac is (depending on how you count it) six generations old.

4k video is one of the most demanding tasks today. I would definitely suggest getting a new top-spec iMac, at the minimum.

 

[CH12671]

I'll keep saying it because apparently I'm dawning my invisible cloak again....PROXY MEDIA
I don't have any graphs to support my idea
Proxy Media
Proxy Media
Proxy Media

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Proxy Media

 

[Scott2014]

I'll keep saying it because apparently I'm dawning my invisible cloak again....PROXY MEDIA
I don't have any graphs to support my idea
Proxy Media
Proxy Media
Proxy Media

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Proxy Media

Okay. And now I must ask my stupid question: What is Proxy Media?

Please explain in the simplest terms possible, otherwise you'll most likely just leave me confused.

 

[CH12671]

When you import media into an event for a project, you need to click on "create proxy media." This will put a lower resolution clip in your event to work with. Once you share the media, FCP will re-optimize it for you, giving you a full resolution output.

What version of FCP are you using?

 

[joema2]

When you import media into an event for a project, you need to click on "create proxy media." This will put a lower resolution clip in your event to work with. Once you share the media, FCP will re-optimize it for you, giving you a full resolution output...

Proxy media is 1/4 the size of ProRes 422, which itself may be 10x the size of a highly-compressed camera native format. E.g, say the 4k camera captures in AVCHD, it is probably writing about 7 gigabytes every 10 min to storage.

That 7 gigabyte file if converted to ProRes 422 might be 70 gigabytes. Fortunately Proxy media is only about 1/4 the size, so it's "only" 17.5 gigabytes, or double the size of the camera native files. Generating those proxies is a transcode, so this also takes a long time on an underpowered system.

So proxy media does enable HD or even 4k editing on some lower-powered systems, but it's not a magic solution. At 4k you still need lots of disk space -- even for proxy files -- and you pay the time penalty of the transcode.

If the OP wants to give it a try, have at it. Before even getting the 4k camera, he can probably find some 4k camera native files to download and try editing. I think he'll find it doesn't work well (maybe at all) on his 2008 iMac, but I say give it a try and post his results here.