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General Guide to Building a PC for Flight Simulator X

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#1 lnewqban


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Posted 15 June 2012 - 09:13 PM

General Guide to Building a PC for Microsoft Flight Simulator X

By: Juan Hernandez (Lnewqban)


This guide is for users of Microsoft Flight Simulator X (10) who are experiencing issues with performance and want to build a PC for FSX.

This general guide should be read first before asking questions about specific hardware and will cover general concepts users should be familiar with that deals with how the game works and how it interacts with various PC components.

Users must be careful in choosing who to get advice from, and this article should only be the first source that they listen to. Therefore, I claim no responsibility for their decisions.

For reference, I have two and a half years of experience with FSX, I have built three computers with different hardware configurations and as a result I have observed how different brands of hardware affect FSX performance.

Brief History of FSX:

In 2006, when FSX was being developed, CPUs (Central Processing Units) were single-core processors with their clock speed determining primary performance. Microsoft (ACES Studios) thought that as time went on the clock speed of CPUs would become increasingly faster, and that we would eventually reach speeds close to 10 GHz at the end of the decade. This didn't happen.

So, when ACES Studios were developing FSX, they thought they would be able to keep the same game engine they had initially developed back in 1999, during the FS2000-era. This engine relied on processor speed (3.0+ GHz) to function fluidly. As you can see, the problem arose when modern CPUs with multiple cores were introduced, but at much slower clock speeds (2.0-2.5 GHz) than ACES Studio had anticipated. As a result, FSX does not run well on most systems that don't have a CPU clock speed in excess of 3.0 GHz. In fact, the official Microsoft Flight Simulator X site lists a recommended processor speed of 3.6 GHz! The irony is there are few consumer processors that come with a stock speed of 3.6 GHz, even today. So, how does one achieve such a recommended high clock rate? This is what is called overclocking – Running the processor at a frequency much higher than its stock speed.

NOTE: Be aware, overclocking can potentially damage a processor if insufficient after-market cooling is present. However, overclocking is what gives FSX its greatest increase in performance. For now, I will concentrate on explaining how FSX interacts with CPUs in a general way and this should help users understand why overclocking increases performance later on.

The faster the processor, the more it can process in the quickest amount of time. The more it can process means a more fluid gaming experience. This is in direct contrast to modern coding techniques that place a majority of the visual rendering on the GPU (Graphics Processing Unit; Video Card).

Since users are now familiar with how FSX functions on a very basic level and why a fast CPU is what determines FSX performance more than any other component, this leads me to the next section of the guide…

How FSX Interacts with Each Component of the PC:

CPU: We'll talk more in-depth about the CPU here.

In addition to rendering visuals, the processor is also processing a lot of mathematical calculations to simulate flight and other dynamic forces like weather, ATC (Air Traffic Control), etc. This is why FSX needs a fast processor compared to standard video games.

In terms of the number of cores FSX uses, there is a lot of confusion surrounding this question and whether, or not, this effects performance at all. It should be noted FSX is not multi-core enabled by default. However, after Service Pack 1, and 2 were released and multi-threading was enabled, FSX is able to allocate some of its processing to more than one core. In standard configuration, FSX allocates most of its resources on the first core of the CPU (Core #0). For multi-core CPUs, FSX allocates some of its less intense tasks (namely autogen rendering) on the second core of a multi-core CPU (Core #1). If a user has a quad-core CPU, FSX will allocate even fewer tasks on the third and fourth core (Core #2 and #3). Performance, however, might not be improved significantly when using CPUs with more cores, unless a specific tweak such as the "AffinityMask" is used. The overall frames per second (FPS) might be smoother, but not higher, necessarily.

Therefore, it is highly recommended users wanting acceptable FSX performance should have a dual-core CPU at the very least, and one with a fairly high clock speed of e.g. 3.0 GHz, or more.

As discussed, FSX does not require more than two cores at the most to function fluidly, so users do not have to worry if they are on a low budget. FSX will function well with a quad-core, but if users are forced to choose, a dual core with a high(er) clock speed is preferred over a quad-core at lower clock speeds. The ideal configuration is a quad-core at high clock speeds, or with the newer architecture, for example, "Sandy Bridge".

As far as specific processor brands, users should opt for an Intel CPU over an AMD for FSX because Intel processors are usually better when it comes to power consumption and heat. There is usually much more support on FSX forums for Intel, as well.

RAM: I'll begin first by talking about the amount of RAM needed for FSX.

It is highly recommended users have a bare minimum of 2GB (Gigabytes) of RAM for most modern PC applications. However, running 2GB of RAM is also the bare minimum for FSX because it can give users Out of Memory (OOM) errors. These errors occur when more textures from FSX are being loaded onto the RAM when there is not enough RAM available.

Therefore, it is highly recommended users invest in 4GB of RAM, or more to avoid Out of Memory errors.

NOTE: To be able to utilize a full 4 Gigabytes of RAM, users are required to run a 64-bit OS (Operating System). This is because standard 32-bit operating systems cannot use RAM above 3 Gigabytes. So, users should take this into consideration before they upgrade their RAM since this upgrade might also force an OS upgrade as well that might increase the overall cost.

Now, I will explain different types of RAM.

There are two types of RAM on the market right now: One is DDR2, and the other is DDR3. DDR3 is the most current type of RAM and the fastest type. DDR2 is slightly slower, but still very fast.

Now that we know what the two types of RAM are, we can discuss how the RAM speed affects the performance of FSX.

FSX, like all programs, loads work and other data in the RAM that will be processed by the CPU. The more RAM available that is present, the more data it can load, obviously. The speed and bandwidth of RAM affects how fast the RAM can move data over to the CPU and the graphics card. Hence, this is why speed of RAM affects the overall performance of FSX.

For example, DDR2-1066 RAM will perform better than DDR2-800 RAM, because the bandwidth is faster on the former. That means there will beshorter wait times for the CPU to receive the data it needs to process. The same exact principle applies for DDR3 RAM.

Graphics Cards: Even though a graphics card is not the most important component when determining performance in FSX, it is still vital to be able to run all of the visuals improvements FSX offers over previous versions of Flight Simulator.

FSX loads most of its visual textures on the graphics card RAM, known as "VRAM", Video RAM. VRAM stores textures and frame buffers required for high resolution gaming.

Typically, the bigger the texture FSX needs to use, the more VRAM is required to store and then process that larger texture. So, using a graphics card with more VRAM is more ideal for FSX because this means more textures can be stored at any one time. The more textures that can be stored means a shorter wait time for those textures to be processed by the GPU. Therefore, faster VRAM speeds and types (GDDR2, GDDR3, and GDDR5) can enhance the speed in which these textures are processed.

It should be noted users wanting to purchase graphics cards with two GPUs on one board, or use two graphics cards in combination (NVIDIA SLI, or ATI CrossFire) are strongly advised not to do so for FSX. This is because FSX is not optimized to run two GPUs at the same time, regardless of configuration.

As far as choosing specific brands of a graphics card, users are advised to go with a NVIDIA because FSX was optimized for that platform. FSX stores most of its textures in DDS (.dds) file format that is a proprietary NVIDIA compression format. This format first needs to be decompressed before being stored in the VRAM. NVIDIA decompresses these files faster. Hence, this is one reason why they perform better than ATI in FSX.

Another big difference between platforms is FS's image quality. Nvidia's drivers have a specific AA mode that ATI doesn't, called the "combined" mode. What this mode does is use both normal multisample AA, which smoothes the edges of polygons, and a supersampling componet, which smoothes the entire scene, including the insides of polygons (textures) and what are called alpha-test objects - the trees, fences, power pylons and so on (anything that looks like it's composed of flat 2D pieces basically).

ATI has two modes essentially - multisampling only and supersampling only. The problem with supersampling-only is that it is extremely intensive on the GPU - it works by rendering the scene internally at a higher resolution (double for 2X SSAA, quadruple for 4X SSAA and so on) and then using that higher resolution image as the "map" for how to blend the pixels to smooth the image. So, if one’s running 1920X1200 and they want say, 4X SSAA, they're actually rendering the sim at both 1920X1200 and at 7680X4800. That puts a huge amount of strain on the card, much much moreso than standard multisample AA. The problem with multisample AA of course is that it only gets polygon edges; it can't touch the insides of polygons or the alpha test objects. This is why one sees "shimmering" usually if they just run a pure MSAA mode.

The mode everyone uses with FS is called "8xS" - this breaks down to a 4X MSAA filter and a 2x1 SSAA filter together. The "2x1" means that only the horizontal resolution is being rendered at 2X the displayed resolution for creating the SSAA "map". So basically it's a lower quality version of supersampling. The net effect though is that one can get something that looks very close to full blown super sampling, but without basically any of the performance hit.

It’s worth noting that the combined mode is hidden by default in the Nvidia drivers. One has to use an application like nHancer or Nvidia Inspector to actually enable it in the FS profile. It is there though and the ATI driver doesn't have anything like it. In most games, the combined mode isn't actually useful, it's still too slow, but because FSX is so CPU-bound, users can use it without problems since the video card is massively underutilized to begin with.

Now, with respect to the hardware itself, I personally don't think it's really accurate to say that either is better - they constantly one up each other with each product revision. If one plays games other than FS, they'll see this on the various review sites. The ATI Radeon 5850 and 5870 were definitely the best cards out there before the Nvidia GTX 4xx series was released. It is true that they use slightly different methods as far as their shader processors go, but it's very hard to say that either method is inherently better than the other. In games other than FS, the ATI cards are perfectly fine.

In conclusion, users are advised to purchase an NVIDIA graphics card that fits their budget that has as much VRAM as possible. For specific models, users should research various gaming and Flight Simulator forums (like this one) to find out exact performance, benefits and cons before making their final purchase.

Operating System: Operating systems (OS) have the least influence on performance in FSX. However, it is necessary to know which operating system is best suited for a user's needs, as well as how to optimize it for FSX.

As mentioned previously in the "RAM" section, FSX is a 32-bit application and cannot use more than 4GB. In order to use 4GB of RAM (or more), a user must have a 64-bit operating system installed. OSs with the least amount of software preloaded (“bloatware”) are recommended, as more hard drive space can be used for FSX.

Hard Drive:

In choosing a hard drive, users are advised to purchase a 7200 RPM (Revolutions Per Minute) hard drive. This speed is recommended because like RAM, the faster data can be loaded into RAM and then processed by the CPU means increased performance.

In terms of hard drive interfaces, SATA (Serial Advanced Technology Attachment) hard drives are more or less the standard now and can make a big difference in loading times versus old IDE (Integrated Drive Electronics) drives. IDE is slower due to the older technology's bandwidth limitations. SATA interfaces are faster in large part due to their point-to-point connections that allow them to only need a single four-wire cable versus the older, ribbon interfaces IDE drives use. Solid State Drives (SSD) are available and are reported to load textures much quicker, but they are very expensive and do not provide as much space as traditional hard drives do at the current time.

In addition to drive speed interface, users are advised to put FSX on a separate hard drive that is separate from the OS. This will keep the hard drive clean(er) and defragmented less versus having it on the same drive with the OS. Consequently, the time it takes for the loading bar in FSX to complete is dependent on the speed of the hard drive, and not necessarily the CPU.

Also, RAID arrays (0, 1) have ZERO effect on any game performance, regardless of what so-called experts claim. The two most common RAID arrays used are RAID-0 and RAID-1. RAID-0 does affect the speed of writing data into the drives. As users write half the data into each drive they get double the speed (in theory) but at least a performance boost when writing data. This will not affect gaming though, as users often don't write data to the drive while gaming. Although, if users copy something from one place to another in the OS environment, then they will notice a difference. For RAID-1, this is mostly used for security (backup) reasons. If one drive crashes, users still have the other intact with all the data on.

Motherboard: This is one of the last components that users most consider. It will join all of the parts to work together.

Users must think about what features they want and the compatibility that it has with the parts that they chose before.

Power Supply: The PSU is simply used to power all of the parts of the PC.

It is the last thing users must consider before ordering all of the components of their new build. They must calculate the amount of electricity that each part will need and add them all up. Later, they must see if it is compatible with all of their parts that they will need to connect it with.

Case: This is to hold all of the components together.

Users must make sure to calculate how much space they will need inside of it, as well as the the space needed to place it in their desired room. Just like the motherboard, they should find out if it has all of the features they need.


As you can see, this guide has covered many different aspects of hardware that influence performance in FSX.

FSX was made in a poor manner and at a time when the hardware industry was taking a different direction than to what the developers thought.

Users are advised to purchase a CPU that can be overclocked to achieve better performance. Fast RAM is needed to ensure a quick transfer of data between the RAM and CPU. Users must be aware that they must also purchase a certain high amount of RAM to ensure stable performance and they must know that FSX can only use a maximum of 4GB of RAM. A NVIDIA graphics card is strongly recommended for smoother and better performance because of the topics covered previously. SLI and CrossFireX are highly discouraged and it is not needed. More VRAM is like RAM by providing better visual performance. A fast hard drive with optimized configurations is vital to handle all of the tasks and data loaded onto it.

Once these concepts are understood, users will be more prepared and confident when deciding on which hardware to choose for their new PC.

That's all you need to know for becoming an educated PC builder for FSX! Good luck on building your new PC, and have fun and learn while doing it!


-Intel vs AMD: "Intel vs AMD Processor Comparison 2012" by Buzzle.com (http://www.buzzle.co...arison2010.html)

-Info on RAID arrays: (http://www.hardwarea...nt/topic/67628/)

-"John" from GearDownFS contributed info to the "hard drive" section

-Info on VRAM: "Flight Simulator X Custom Settings Guide" by ProFlightSimMedia on YouTube

-General info about FSX PC part interactions and history: "For Your Consideration: Flight Simulator X" by The Follys of Flight Simulator (http://flightsimulat...mulator_05.html)

-Info on history of FSX and CPU core usage: "Building a PC for FSX" by GoArticles (currently offline)

-Info about graphics cards (ATI vs NVIDIA) by PMDG developer.

All other information presented was from general knowledge collected from the past few years on many other websites, and trial and error on my own machines.


Lnewqban - Primary researching and writing

ProFlightSimMedia - Additional information and revision

Anonymous PMDG developer - Additional information

"John" from GearDownFS - Additional information


Copyright 2012 - Lnewqban

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