Apple explains benefits of 64 bit mode

[pdube]

Logic has been updated to 64-bit, but the interesting note I found is this document http://support.apple.com/kb/HT3989 in which Apple briefly explains the benefits of 64 bit DAW apps:

What advantages are there to using 64-bit mode?
The main advantage is that you can address vast amounts of memory. With 64-bit mode, the application memory is not limited to 4GB as with 32-bit applications, so there is essentially no practical limit by today's standards. As a result, all the installed memory that is not needed by the OS is available for use by Logic Pro or MainStage, which can be meaningful if your Mac has more than 4GB of memory installed. This larger amount of memory allows you to run far more instances of memory intensive plug-ins, such as sample-based software instruments.

Later in the document, Apple notes that users shouldn't expect big performance gains in Logic itself from switching to 64 bit mode:

Do Logic Pro or MainStage perform better in 64-bit mode?
Logic's processing has always been highly optimized, so in most cases there are only nominal performance improvements when running in 64-bit mode, other than the ability to run more instances of third-party memory intensive plug-ins. However, since Mac OS X v10.6 Snow Leopard is highly optimized for 64-bit operation, there may be some performance gains in areas where Logic interacts with it.

64 bit operation has been debated here. Maybe the above can provide some guidance.

There are more interesting items, with links to other interesting things, like a 32 bit Audio Unit bridge that lets 32 bit plugins run in 64 bit Logic (with certain restictions). I don't know if it's limited to Logic, forcing MOTU to write their own.

[michkhol]

People often complain that Logic 9 is a memory hog, so instead of optimizing the 32 bit version Apple preferred to release a 64 bit one. This is of course a big benefit for Apple to silence those complaints. I see no other benefits here, the memory problem for sample playback already has several solutions like direct disk streaming (Kontakt), separate 64 bit hosts/slaves (Vienna Ensemble Pro), etc.

[pdube]

People often complain that Logic 9 is a memory hog, so instead of optimizing the 32 bit version Apple preferred to release a 64 bit one. This is of course a big benefit for Apple to silence those complaints.

They are saying that 64 bit does little very little for Logic itself, or any DAW for that matter. Optimizing Logic is not what 64 bit mode is supposed to do. They are saying the benefit is largely for plug-ins, and it would likely apply to any 64 bit DAW software including DP. There have been lots of questions in the forums about what can be expected from a 64 bit DAW. The document cited above appears to be Apple's answer in brief form.

I see no other benefits here, the memory problem for sample playback already has several solutions like direct disk streaming (Kontakt), separate 64 bit hosts/slaves (Vienna Ensemble Pro), etc.

Well the benefit you get may depend on how you use the information. There may not be a benefit on older Macs, or Macs not using the Nehalem architecture. The biggest improvement will be on a computer that can hold lots of fast memory and has the architecture, in terms of memory to processor connections, to take advantage of it. The solutions you list are viable and make sense in some situations, like if you have old computers around that can be used as slaves, but those solutions add complexity to your setup, and complexity often leads to trouble. If 64 bit eliminates the need for separate computers and for managing samples and applications across multiple disks, I'd consider that an improvement.

You can also use the information to make buying decisions. Since they're saying 64 bit is a memory issue affecting plug-ins rather than the performance of DAW software itself, you may be able to buy a cheaper Mac and less memory if you use a lot of outboard equipment instead of plug-ins,. The same could be true if you're mostly dealing with recorded audio rather than sample playback. It may not make sense to expect big improvements from 64 bit if you buy an iMac with 16 gig of memory on which you plan to mostly record live performances. However, if you buy a Mac Pro with 32 gig of memory and use a lot of plug-ins with high quality samples, you may see a big improvement from 64 bit.

[David Polich]

I know we've debated the benefits of 64-bit here before. One thing that
still amazes me is that I run into people who think 64-bit sounds better...like it's an audio spec. I think this is the biggest single
misconception about 64-bit processing.

[michkhol]

They are saying the benefit is largely for plug-ins, and it would likely apply to any 64 bit DAW software including DP.

One "benefit" is for plugins that use a lot of memory. The other potential benefit is that in 64 bit mode the Intel processor has twice more available registers which in theory and with proper optimizations can reduce the time spent on sending data back and forth between CPU and RAM.

If 64 bit eliminates the need for separate computers and for managing samples and applications across multiple disks, I'd consider that an improvement.

It's a big "if". Lifting the memory limit immediately reveals other bottlenecks - the CPU and disk I/O. Generally it is hard to predict precisely the complexity of a given project except that it will be more complex over time. So if you start on one computer and hog the CPU, the cost of going to the distributed environment may outweigh the cost of maintaining that environment from the very beginning. If you use up the resources of a particular distributed configuration you just add more computation units, that's all. A single-computer environment does not scale.

[pdube]

Agreed, you can overload any single machine. You can create such a heavy workload that even a distributed system fails because you have so many machines that you spend all your time patching and troubleshooting them. That's a different type of limited scalability. We each have to pick our poision, I guess.

What I like is that over time it has taken a heavier workload to overload a single machine. As is so often the case with computers, 64 bit mode may or may not help in that regard, depending on the hardware/software available and how it is being used. People have been asking about 64 bit and Apple gave a little guidance, so I thought I'd share it because it can lead to further discovery and may even help when evaluating performance, troubleshooting, or making purchasing decisions.

[Shooshie]

I know we've debated the benefits of 64-bit here before. One thing that
still amazes me is that I run into people who think 64-bit sounds better...like it's an audio spec. I think this is the biggest single
misconception about 64-bit processing.

Of COURSE it sounds better. Just try it: say "32 bit." Ok? See how small and wimpy it sounds? Now say (in a deeper, Darth Vader voice, if possible) "64-bit." There. You see? It sounds... well... TWICE as good! Why stop there, though? I think "1024 bit" would sound incredibly heavy! Surely that would fatten up your low end and spank those highs.



Technology marches on, but Mythology stays many leaps ahead of it.

Shooshie

[pdube]

Yeah, there's lots of confusion on the sound quality. This was on AppleInsiders story about the Logic upgrade:

The company noted that there is no difference in sound quality between running the applications in 32-bit or 64-bit modes. Prior versions of the software used 64-bit processing resolutions for plug-ins when it was decided there was an audible benefit.

What is a 64 bit processing resolution?

[newrigel]

This is the reason for Apple developing the Light Peak technology because it removes that bottleneck and QPI makes the FSB a thing of the past as far as bridges to and from the CPU to ram...
They have moved the PCI and other controllers on die which helps also...

[papageno]

As explained before, the advantage of the host app. being 64-bit is mainly for VIs loading samples in RAM. The memory limitation of 32-bit apps is really too small, nowadays CPUs can handle a lot of RAM.

I am very happy with NI-s approach, started in Kontakt 3.5 and continued in Kontakt 4. The possibility to use memory server has a few advantages:

* doesnt matter if the host app is 32 bit. All samples are loaded to memory server app, outside the host.

* samples can be unloaded manually- changing the audio buffer size in DP takes so much less time now because the samples stay loaded in the memory server if the corresponding option is selected in Kontakt.

The only downside is that I sometimes forget to purge/unload the samples and RAM will fill up.

[michkhol]

What is a 64 bit processing resolution?

It's when you use 64 bits per sample for calculations, either integer or floating point.

[michkhol]

This is the reason for Apple developing the Light Peak technology because it removes that bottleneck and QPI makes the FSB a thing of the past as far as bridges to and from the CPU to ram...
They have moved the PCI and other controllers on die which helps also...

It is actually Intel's and it is for peripheral data exchange only. It does not help CPU because the CPU still performs only a certain number of operations per time unit and it does not help disk I/O because no matter how fast the data transfer is the disk is still much slower.

[newrigel]

This is the reason for Apple developing the Light Peak technology because it removes that bottleneck and QPI makes the FSB a thing of the past as far as bridges to and from the CPU to ram...
They have moved the PCI and other controllers on die which helps also...

It is actually Intel's and it is for peripheral data exchange only. It does not help CPU because the CPU still performs only a certain number of operations per time unit and it does not help disk I/O because no matter how fast the data transfer is the disk is still much slower.

OK: http://www.engadget.com/2009/09/26/excl ... -could-be/

Engadget has learned -- thanks to an extremely reliable source -- that not only is Apple complicit in the development of Light Peak, but the company actually brought the concept to Intel and asked them to create it. More to the point, the new standard will play a hugely important role in upcoming products from Cupertino.

AND it can be implemented for any type of data and it has been shown http://www.youtube.com/watch?v=khPx1dEIPnA copying huge files... so you do record to a FW drive right? This would make it look like a floppy drive.
But the reference to QPI is no more FSB to/from anything... it runs 1:1 with the clock... so when speed step kicks in, it's faster there too...
My post was just referring to the advance towards the greater B/W 64 bit will require and that the infrastructure for that is being put into place as we speak... could be in the next MP's.
I don't know if on your system when you change the buffers the processor have to work harder... so wouldn't the DSP performance be effected in the DAW? The faster the drive bandwidth the easier it is on the processor for those tasks. Yes, the DSP needed for plugs has nothing to do with disk activity unless it's a VI accessing audio files to stream from disk or anything along those lines, but opening up the I/O to and from anything is going to help the processor with it's tasks @ hand overall.

[Larry Mal]

I want to say this about it: having used it for a couple of days, it has become very clear to me that the 32 bit version of Logic 9 was just not what it was supposed to be- it used RAM much more poorly than version 8, and error messages slowing work down was common.

Since it's gone 64 bit, it's much more stable- I was telling folks here that I slapped together a 35 audio track project, with four or five convolution reverbs, linear phase EQ on every track, and a scattering of other plug ins, all running at 96k. This project (which originally didn't have all of that, I'm no maniac) was done on 8, ran very poorly on 9, and now is running like a champ on 9.1.

Now, I know they didn't optimize the code much, and I can't explain why it's handling things better that are CPU intensive like this- there are no VIs on this, and the real world RAM use is only about 2.5 GBs. But, this was often the actual limit to Logic, and I can't say if it's using virtual memory a lot less and that's what's making it stable or what.

But I'm digging it- it's actually very cool. When I'm done with what I'm doing, I'll try and dig more into it.

Anyway, just to let you all know.

[pdube]

If you get a chance to dig in, I'd be interested to know if you found that the performance improvement is mostly in the host or the plugins. It may be some of both, but is it weighted toward one or the other?

The memory server mentioned above is interesting because it does seem to remove the 64 bit issue. I can't help but note though, that while the memory server solves one problem, it creates another when papageno forgets to purge/unload. Adding more parts to the system increases the amount of management required. And then there is the possibility that changes to the host will eventually have a negative impact on the performance of the memory server. Again you have to pick your poison: go with 64 bit in the host and trust the host developer or take the added time to manage the memory problem yourself.