LEGION - Improving Simulation Time by Optimizing Hardware Configuration


 Product(s):LEGION Simulator
 Version(s):CONNECT Edition
 Environment:N/A
 Area:Simulation Speed
 Subarea:N/A

Problem Description

Are there any hardware, OS or software tweaks that can help to decrease Simulation time while handling very large models with high passengers attendance?

Steps to Accomplish

Since LEGION Simulator is single-threaded it cannot take advantage of multiple cores.  Marginal gains might be seen in multi-core stand-alone setups because the operating system can dedicate hardware to a simulation instead of sharing CPU time, but this is negligible.

If you are looking to optimize your hardware configuration for LEGION simulations, the tips below may help to achieve improved speed.

PROCESSOR

If you are looking to specify a system, we recommend a 64-bit processor, which may execute some code faster than a 32-bit processor because it can move more data per clock cycle.  However, the main benefit of a 64-bit processor is the amount of memory it can access.  Applications running on a 32-bit processor in Windows can access 3GB of RAM at the absolute maximum, or else only 2GB without BIOS support for using 3GB.  Windows 32-bit itself can use at most 4GB of RAM, but each application can only use at most 2GB, or 3GB depending on BIOS settings.

Crucial CPU factors are:

It’s worth noting that faster CPUs tend to have more cores.


OVERCLOCKING

Some processors can be overclocked to run at a higher speed than their nameplate speed.  This will increase performance, but comes at the cost of needing more power and better cooling. 

To get the best from an overclocked CPU you need to also overclock the ancillaries such as memory and the memory bus. This further increases the power and cooling demands.

POWER

Faster CPUs and memory generally need more power than slower versions.  Newer generations of CPU and RAM generally need less power than previous generations, but within a single generation faster needs more power.

It’s important that your power supply has sufficient margin to operate correctly under demanding loads.  We recommend a 20% power margin for your power supply.  If you expand your system at any point, you should always re-evaluate the power requirements and upgrade the power supply if necessary.

COOLING

Fast means hot!

The faster a CPU and memory runs, the more heat is generated.  If that heat is not removed quickly and effectively, the CPU will automatically slow the system to protect itself.

A well-cooled PC will run with far greater stability than a PC that is only just adequately cooled.  It can also be overclocked far higher.  Generally, the colder a CPU is, the faster it can run.

A variety of cooling options are available, from basic fan + heat-sink combinations, to exotic liquid-cooled systems.

It’s not just the CPU that needs to be cooled.  Memory and graphics processing performance also benefit from effective cooling.

Remember to account for the cooling system’s power requirements in your power budget.


VENTILATION

Getting the heat out of the PC is one thing, but if that heat has nowhere to go, it will accumulate around the PC and you may end up in a situation where hot air is used to cool the PC.  This doesn’t work well, and puts increased strain on the cooling system.  The CPU and other systems will tend to run hotter, so this is not optimal.

Your PC(s) should always be in a well-ventilation location, where expelled heat can dissipate or be removed without recirculating into the casing and cooling systems.
 

MEMORY BUS

This allows the CPU to communicate with the system memory.  It’s important the memory bus speed and bandwidth is matched to the CPU and the memory, otherwise it becomes a communication bottleneck and the CPU spends a lot of time waiting for data from memory.


MEMORY

Large models need more memory than small models.  Complex models need more memory than simple models.  Large and complex models need significantly more memory.

Model complexity derives from many elements, including (but not limited to):

We recommend maximizing installed memory, but remember that only 64-bit processors can use more than 4GB.

Crucial memory factors are:


HARD DRIVES

Ideally, your PC will have one drive for the operating system and use other drives for recording data.  This minimizes input/output conflicts when both Windows and Legion products are trying to access drive data at the same time.

We recommend the fastest drives you can afford.  There are numerous options available.

For traditional, spinning drives, the key factors are:

For Solid State drives (SSDs), rotation speed is not an issue.  These drives tend to have lower capacity than traditional drives, but access times and data transfer rates are much better.  The trade-off is in monetary cost and a limit on how often data can be written to the same memory “cell” of an SSD before degradation.  Write limits are improving with each generation and more expensive units typically last longer.  But longevity should still be a consideration.


GRAPHICS

Graphics must fully support OpenGL and must be discrete – either NVidia or AMD.  We recommend only genuine NVidia/AMD rather than any cheaper imitations and cannot guarantee functionality on such.

We do not support integrated graphics e.g. Intel. LEGION Model Builder and LEGION Simulator make limited use of the graphics card: basic OpenGL functionality for segment rendering and geometric operations. Remember to factor graphics card consumption into cooling and power requirements.