64 bit versions of Windows have two distinct advantages over the 32 bit versions. In the first case 64 bit Windows delivers a higher performance for users undertaking computation-intensive tasks like real-time analysis of acquired data or on-the-fly signal generation.
Secondly, the 64 bit Windows versions support clearly more memory than the 32 bit versions. 32 bit Windows can address a maximum of 4 GByte of memory of which one part is reserved for the kernel and another part as address space for bus extensions. As a maximum there are 3.5 GByte available for application data. Compared to this, the theoretical available address space of a 64 bit system is 16 ExaByte (4 GByte * 4 GByte). The physical maximum of memory depends on the motherboard and the Windows version and is usually around 128 GByte.
The use of the 64 bit driver version can extremely extend the usable memory of Spectrum digitizers and AWGs without the need of a cost-intensive on-board memory upgrade. Most of the PC instruments on the market can only use the on-board memory for data storage and need to transfer data after the end of the acquisition to PC. The Spectrum instruments instead allow the continuous data transfer to PC memory with a transfer speed of up to 220 MB/s (PCI-X slot) while doing acquisition. Assuming a recording of 2 channels at 100 MS/s and 8 bit resolution (M2i.2030) a total of 190 MByte have to be stored per second. A Windows 32 bit system is only able to record a maximum of approx. 18 seconds even when equipped with full 4 GByte of memory. Compared to this a Windows 64 bit version is able to record several minutes of data.
The 64 bit support of the M2i cards also allows to use older 32 bit programs – thus without the advantage of the extended address space. The Spectrum 64 bit Windows drivers support the common Spectrum API making card programming identical under Windows 32 bit and 64 bit as well as under Linux 32 bit and 64 bit. A change from a 32 bit Windows version to its 64 bit pendant therefore is only a question of simple re-compilation.
The 64 bit Windows drivers can be downloaded free-of-charge from the Spectrum homepage www.spectrum-instrumentation.com.