• 64-bit

Questions and Answers about 64-bit

Q: What does "64-bit" mean?

A: A 64-bit computer, operating system, or software application is able to use 64-bit wide memory addresses, while a "traditional" 32-bit computer, OS or software can only use 32-bit wide memory addresses. The maximum memory address space for a 32-bit system is 2³², which equals 4gigabytes. A 64-bit system can address 2⁶⁴ bytes, that is 17,179,869,184 gigabytes.

Q: What do I need to make use of 64-bit computing?

A: You need:

• a 64-bit computer, like Mac equipped with G5 or Intel processor; a PC equipped with AMD64-architecture processor (Opteron/Atthlon64) or Intel EMT-64 processor (some Pentium4 and Xeon; the Core series), or Intel Itanium processor

• a 64-bit operating system, like Windows XP 64-bit edition, Windows Vista 64-bit version, or Mac OS X version 10.5 ("Leopard") or above. (Mac OS X was partly 64-bit in versions 10.3 and 10.4.)

• A 64-bit software application

Q: Is ArchiCAD 64-bit?

A: From version 13, ArchiCAD has a 64-bit version for Windows. When you install ArchiCAD on a 64-bit Windows operating system, it will automatically install the 64-bit version.

Q: What is the benefit of 64-bit ArchiCAD?

A: You can work with larger projects. On 32-bit systems if ArchiCAD's memory usage is close to the memory address space limit, then ArchiCAD might abort operations with "not enough memory to finish operation" error message, or can even crash. On 64-bit system this barrier is completely eliminated, and the only limit is the size of the physical RAM in your computer.

Q: Is 64-bit ArchiCAD faster than the 32-bit ArchiCAD?

A: It depends. If the only change to the computer is a new 64-bit operating system, it is likely that ArchiCAD will operate slower. The reason is simple. When ArchiCAD opens a project in 64 bit mode as opposed to 32-bit mode, the pointers to memory are double the size. That is, every object, in the project now will have a pointer to it that is 64-bit instead of 32-bit. Depending on how many objects are in the project, the additional memory for the pointers could add up to 10-20% of the original file size. If the project was already using virtual memory, it will be using 10-20% more virtual memory in 64-bit mode. Virtual memory can be thought of memory that is slower than the computer's hard drive. Depending on how fragmented the drive is, and the use of indexers and virus checkers on this drive a significant performance penalty could be incurred for the lack of physical memory.

The point is, it is not enough to change the operating system -- memory must be added. And performance gains will only be visible where memory use was intensive. For instance a send and receive with a project that was particularly memory intensive went from 10 minutes to 30 seconds after adding 4GB. Where memory was not in shortage a notable speed gain will not be noticed.

Q: How much RAM can should I put in my 64-bit computer?

A: To make use of the extended memory address space of a 64-bit system, 4GB is the bare minimum, but you should preferably have 8GB or more. It also depends on how much can the motherboard of the computer take, and how much is recognized by the system. E.g. Windows Vista Home Basic operating system has a limit of 8GB, the Home Premium edition handles up to 16GB, and the Business/Enterprise/Ultimate edition can deal with more than 128GB. You will not need that much for ArchiCAD any time soon.

Q: Why is there no 64-bit version for Mac?

A: Converting ArchiCAD to 64-bit on Mac is a magnitude bigger work than on Windows. This is because ArchiCAD is a “Carbon” application – as the majority of the Macintosh applications with 8+ years history. Before ArchiCAD can go 64-bit, it has to go Cocoa. This is a result of Apple's sudden decision in 2007 to stop 64-bit support for the Carbon API. Graphisoft has already started work on 64-bit Carbon ArchiCAD when this decision came, so we had to restart work on Cocoa basis. This is a huge development work, but we hope that the first results will come in ArchiCAD 14, where the BIM Server that is designed to host and serve numerous large projects will be 64-bit compliant on the Mac as well. However, since Mac has a superior memory management that allows ArchiCAD to use up to 4 GB of RAM, memory shortage is not a typical problem on Mac.

Q: Can ArchiCAD run in Mac OSX 10.6 Snow Leopard 64-bit kernel mode?

A: ArchiCAD can run in 64-bit Kernel mode if you have installed WIBU driver version 5.30. As of today, (September 2009) only recent XSERVE machines run in 64-bit kernel mode by default, and most of the recent Macs can also be forced to run in 64-bit Kernel mode. However, 64-bit applications work with 32-bit Kernel as well, and 64-bit Kernel mode is really only necessary if someone wants to use more than 32GB of Memory. All the external peripherals (like printers) need to have 64-bit system extensions in this case. Read more here: http://www.appleinsider.com/articles/08/10/28/road_to_mac_os_x_snow_leopard_64_bit_to_the_kernel.html

Q: How much memory can ArchiCAD use then on the different systems?

A: The 32-bit ArchiCAD can use a maximum of 4GB of RAM. However, some operating systems put a limit on this: Windows XP 32-bit and Vista 32-bit imposes a limit of 2GB.

Also read:

• More info on 64-bit on Wikipedia

• About Multiprocessing

• Windows XP 64-bit edition

• Windows Vista

• Snowleopard

• A good summary on 64-bit Mac conversion