The faster the processor used, the faster you will be able to manipulate and solve your LUSAS models. LUSAS is CPU intensive, especially when solving an analysis.  Therefore an increased processor speed will decrease analysis times. A dual-core or multi-core CPU will mainly offer improved efficiency when multitasking with LUSAS and other applications simultaneously. If running LUSAS in the background and you are using another application then one core will be dedicated to LUSAS while another will be dedicated to the other application. In general we recommend that once a large analysis is set to be solved, the computer to be left alone so that the CPU can dedicate itself to solving the analysis. Modeller currently will run on only one core/processor at a time.  LUSAS Solver will use multiple cores/cpus during the "Assembling Elements" stage and Fast Solvers will also use multiple cores/cpus during "Solving equations" process. Some of the latest multi-core Intel processors also have the ability to speed up those cores that are in use, when other cores are not being used (called “Turbo Boost Technology”).

Increasing the processor speed for multi or single processor machines would be virtually lost if there is insufficient physical memory since the analysis would be "disk-bound" - that is, the processors would be spending a lot of their time simply waiting to retrieve data from the system swap file or the application scratch files.

The memory requirements for LUSAS when solving medium to large analyses is typically underestimated when purchasing new machines in our experience. In general, both Modeller and Solver will respond significantly better when the processing can be carried out in physical memory. For this reason, we would recommend at least 2GB of physical memory. Nowadays it is common to get a machine with 4GB in 32 bit systems and 8GB or more 64 bit systems.

If you intend to run large jobs it is strongly suggested to use the LUSAS fast solvers, which can reduce the solving time by a factor of 5 to 10, using multiple processors during the solving of equations.  See Fast Solvers for further details.

Additionally Solver performs significantly better with fast disks. You should always ensure that there is plenty of disk space free (generally > 12GB or 3xResults file size) when running a large analysis as LUSAS temporary files can become quite large and an analysis can also use up a large amount of Windows swap space. Moving large files off a hard disk temporarily, keeping as much space free as possible and in large contiguous blocks and defragmenting the disk regularly will all speed up the reading and writing of large files like results and output files significantly reducing the time Solver is running for large analyses. Solver will also benefit significantly from a fast Hard Drive (and there are various different types available these days) which will speed up reading and writing to disk. If you have two internal local hard drives, then save your model on the one that does not have LUSAS installed on it. If you have three internal drives, have LUSAS installed on one, the model saved on another, and your temporary file locations set on the third. This should help speed things up because reading and writing can occur at the same time on separate disks. Also moving files of the disk you are using temporarily should help to free up space and reduce possible fragmentation of the working files.

32bit LUSAS will work on a 64-bit machine operating in 32 bit emulation mode. A 64bit operating system, and commonly a larger resource of installed RAM on a 64bit machine, will both enable 32bit LUSAS to run moderate to large sized models much faster in memory (in RAM) where paging (swapping to disk) would have slowed things down for the same model on a 32bit operating system. Currently, if LUSAS is run on a 64bit operating system 32bit Modeller will also benefit from being able to use up to the maximum of 4GB of memory (the limit for any 32bit application 2^32 bytes) running in 32bit emulation, allowing larger models to be handled than possible on a 32bit operating system. If you have a 32bit PC, then you can also set the data partition in 32 bit Windows to be 3GB rather than the default 2GB. If you need help in changing the system values to get 3GB per application in 32 bit Windows please email to support@lusas.com for more information. 

64bit LUSAS Modeller (mesh only) and 64bit Solver were released in V15. A full 64bit Modeller is under development for a future release. 64bit Solver can also be used with 32bit Modeller to allow much larger problems (requiring over 4GB of memory) to be solved, the size being limited only really by the PCs operating system and memory resources. A 64bit PC with plenty of RAM may solve large problems (between 2.5GB and 4GB) quicker with 64bit Solver than with 32bit.  However, the main gain of 64bit Solver is the size of problem that can be handled which will be limited by the resources available on the PC. 

The important point is that in 64 bit Windows the memory limit allocated to each 32 bit application is 4GB (2^32 bytes) by default while it could be up to 3GB in 32 bit Windows. Thus although currently LUSAS Modeller is a 32 bit application, we suggest obtaining or upgrading to a 64 bit Windows machine for large jobs. 64 bit LUSAS Solver and the 64-bit Solver results files can be read in the 32-bit version of LUSAS Modeller for post-processing. A 64bit mesh only Modeller is also available if you are creating a model from an imported mesh rather than created and meshing geometry.  A full 64-bit version of LUSAS Modeller is currently under development.

LUSAS Modeller has had a significant amount of work carried out to speed up the graphic rendering. A separate (not integrated), fast graphics card, with a large amount of memory, from a well-known manufacturer (e.g. NVIDIA, AMD or ATI) that specifically claims to fully support (and optimise for) OpenGL would most certainly increase performance in terms of the graphics quality and speed of refreshing the graphics screen. Integrated graphics cards tend to be slower. This choice may not be available with certain small-box PCs, especially laptops. If you are forced to use an integrated display card, LUSAS recommend using the Advanced Software OpenGL driver graphics setting in the LUSAS Configuration Utility. Before installing LUSAS, go to the graphics card manufacturer’s website, download and install the very latest drivers for your card. Recent improvements to the OpenGL implementation in LUSAS have helped in providing faster graphical displays.

For information on the general type of hardware specification for use with LUSAS see PC Hardware Support.