Melda Production offers a fantastic explanation of the whole 32-bit vs 64-bit topic as it relates to audio software, DAW’s, and audio plugins. What we like about this technical article is that it’s written in a way that mere mortals can actually understand it which is no small feat. They really dig in to build the foundation of bits, memory, and computer processor architecture so that the main question can be properly answered. Here’s an introductory teaser but be sure to head over using the link below for the whole story.
Memory – Let’s start by explaining the fundamentals of memory. RAM (random access memory) is a very fast memory, which is used to store all currently running applications and the associated data needed. In our case this would relate to blocks of audio data, D.A.W. software & related programs, virtual instruments and samples etc. If there is not enough RAM memory available to store all of this data, the O/S (operating system) can ‘swap’ part of it onto the hard drive and load it back into memory when needed. However this swapping comes at a cost – speed.
RAM is not the fastest memory in the computer, in fact it is relatively slow compared to the processor speed. First there is ‘cache’ memory, which is similar to RAM, but is in much closer proximity to the CPU. While RAM is connected to the CPU via wires many centimeters in length, called a ‘system bus’, cache memory is usually integrated inside the CPU itself. Unfortunately, it is also more expensive than RAM, so it is usually only supplied in batches of just a few megabytes. Cache is situated between the CPU and RAM, so when looking for data, the processor visits the cache first and only accesses the RAM when the information it needs is not present.
The fastest memory in the computer is called the ‘register’, which is actually as fast as the CPU itself. Most work is done inside it but it’s size isn’t measured in gigabytes, megabytes or even kilobytes. You only have a few hundred bytes, with the actual amount defined by the CPU architecture.
Do you really need more memory?
32-bit systems can address up to around 3GB of memory. This limit must suffice for the whole system and all running applications, otherwise something will get swapped. In addition, there is another limitation for separate applications – usually 2GB. This 3GB limit still seems generous, but besides actual samples it will also contain all executables and temporary files etc. After all these are taken into account, you probably have around 1.5GB free for your project.
Is this enough? Well it usually is, so let’s look at an example of a large audio project. Let’s say that our project needs 3GB of RAM. 1GB of this will be taken by up by executables and temporary structures and so is effectively lost. The remaining 2GB contains the data to be loaded from your hard drive. This data is usually compressed, so we could estimate that with lossless audio compression and the structures needed for random access, we would need to load about 1GB from the disk. Even though modern hard disks have become a lot faster, with fragmentation and simultaneous operations, a fair estimate of the fastest loading speed would be around 50MB per second. Therefore loading all the data will take 20 seconds. Add to this the time to compute the temporary structures, and even with an 8-core processor, it will take 25 seconds to load.
25 seconds to load a project! Do you really want to wait that long? Well, sometimes you don’t have a choice, but this scenario does highlight the disadvantages of using so much memory.
Why have 64-bit architectures been developed?
Frankly, not for audio. The main reason for development was to meet the continuously increasing demands from servers. Unlike D.A.W. programs, which are basically the exclusive main applications when working with audio, servers process hundreds of requests at once using terabyte databases. They also access the data in a virtually random order, so it is necessary to keep as much of the data in memory as possible.
Now that 64-bit processors have been developed for servers, why not use them in other applications as well? Memory was a major issue for developers back in the days of 16-bit architectures. With the arrival of 32-bit systems, speed became the priority and so we started wasting memory until eventually the limit was reached. With the advent of 64-bit machines, the same situation has happened once again. So now we need lots of memory for audio, video, games etc…
Do you need to go 64 bit? It’s probable that within 5 years most computers will be running 64-bit operating systems and therefore most of the applications will also be 64-bit. Until then, can you manage without upgrading? We cover some key details below to help you decide.