Building a CAD Computer

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As an Application Engineer at Studica, a very common question I get is “I’m building new machines for my CAD software to run on. What kind of hardware should I get?” Of course, this question is extremely difficult to answer because of the variety that there is in the computer realm; especially when dealing with PC’s. Also, price-points depend a lot on the economic sector that you are associated with; educational, commercial, government, or personal use. Because of these many variations, I never recommend a specific setup. However, I do inform people of the system requirements and how the different pieces of hardware fit in with Autodesk software and what minimum specs I recommend. This post will go over the fundamental hardware of computers and how they interact with the Autodesk hardware and what you need to know before purchasing a computer system.


Processors are pretty much the most important part of a computer. They play a large role in CAD software. Basically, the computer uses the processor to do everything. All of the calculations a computer makes are handled by the processor.  As such, the faster the processor, the quicker everything runs.

Of course, this begs the question; “what processor should I get?” When shopping for a CPU/Processor for your new machine, think about what you NEED to do with your machine. If you are an architect who simply uses AutoCAD to design 2D layouts, then you do not need a beefy processor. Autodesk’s products all work differently but it’s usually recommended to get a quad-core processor when dealing with design software. The reason for this is for rendering 3D Models. When a command is sent to render a 3D Model in Revit, 3DS Max, Maya, etc. then the computer begins to utilize all of its hardware to complete the task. The more cores that you have on your processor, the more available processing power the software has available to use for rendering. For example, if you go to render a simple model in Revit Architecture and you have a dual-core processor, then Revit will utilize both cores to their full potential until the render job is done. However, if you have a quad core processor and perform the same render; it will get done quicker. This is because Revit then uses all 4 cores to process the rendering. This essentially speeds up the rendering process by two times because instead of just having 2 cores to render, you now have 4 available for the software to use.

Keep in mind that cores are not the only thing to look for. You do want a decent speed on your processor. It’s recommended to at least get 2 GHZ of speed on your processor to run the current Autodesk products. Based on personal experience and client testimonials, I would recommend at least 2.6 GHZ or higher. Most processors nowadays are usually about 2.22 GHZ or higher. Of course, the higher the speed, the quicker things are. Also keep in mind that this speed determines the speed of your individual cores. If you have a quad core processor clocked at 3 GHZ and a quad core processor clocked at 2.5 GHZ and both are rendering the same thing, the 3 GHZ will finish quicker because it has 500 more MHZ of processing speed across its 4 cores. This allows the computer to process the render data quicker.

When you’re dealing with just 2D features such as 2D Drafting and Annotation in AutoCAD, then you may not need more than 2 cores or a 3 GHZ processor. Although, it’s important to note that the processor is always used by idle processes within your Operating System. Remember, the processor is the brains of the computer. Having a slow processor simply means you will have a slower work environment. CAD software is just a part of what the processor is dealing with at any given time. If there’s any item in your computer that you don’t want to short-change, it is the processor.

Currently, you can buy processors that have up to 6 cores. In some cases, you can get two CPU sockets on a motherboard, allowing you to pop two 6-core processors into one computer, creating a 12-core machine. I have talked with clients who use 12 core machines, although I do not recommend it due to limitations with CAD software and using 12 hyper-threaded cores.


RAM (Random Access Memory) is another critical component for computers. RAM will help you multi-task on your computer. For CAD software, RAM is a crucial component. Almost all of Autodesk’s products utilize quite a bit of RAM. I always recommend that you get at least 3 GB of RAM in your machine. Ideally, you will want a 64-bit operating system running 4 GB or more of RAM. If you are utilizing Revit, it’s highly recommended to get at least 4 GB.

Autodesk products are very RAM-intensive. With the introduction of Windows 7 into the marketplace, RAM is becoming a more and more important component. As such, if you want to run your Autodesk products without running out of Memory or running into performance issues, you will want to secure yourself a good amount of RAM.

The standard for RAM right now is DDR3. The standard RAM speed for DDR3 chips is 1333 MHZ. Most of the time you will purchase a computer from a major manufacturer, you will be getting DDR3 1333 RAM.

RAM and Revit

There are some things to note about RAM if you’re going to be using Revit a lot. Revit is extremely RAM-intensive. The computer needs more and more RAM as your project files get larger and larger. One of the most common fatal errors people have when using Revit is a lack of RAM on their machine.  Most commonly, these people are using 32-bit Operating Systems with 2 or 3 GB of RAM. This is not enough RAM for serious Revit files.

As stated above, if you are primarily using Revit, I highly recommend a 64-bit Operating System with at LEAST 4 GB of RAM, if not 6 GB. There is also another limitation with using a 32-bit Operating System and Revit; the 3.25 GB RAM limitation. 32-bit Operating Systems can only read and utilize 3.25 GB of RAM in a system. Even if you have 4 GB of RAM, you will only get 3.25 GB of it when using a 32-bit OS. Also, in 32-bit Operating Systems (mostly Windows XP), programs can only utilize a maximum of 2 GB of your available RAM. In order to really use Revit in a 32-bit OS environment, you need to enable the 3GB switch, which will tell Windows to allow programs to utilize more than 2 GB of RAM. If you do not do this, you are likely to face fatal errors in your Revit. This article describes how to enable the 3GB switch and what it does:

The bottom line is that Revit needs a good amount of RAM. If Revit is your main product, then do not short-change your RAM.

Graphics Card

The next most important component after your processor is your graphics card. When dealing with CAD software, you need to have a good graphics card. Even if you’re only using AutoCAD for 2D Drafting and Annotation, you will want at least a decent graphics card.

Graphics cards used to be a luxury to have in your computer, but nowadays, they are becoming a standard that is necessary just to run your system smoothly. Graphics cards are dedicated to tasks that deal with rendering graphics. This helps take the payload off of your processor so your processor can be used for other basic functions such as running the program or performing different commands within the program. They are a major component for 3D Modeling. Having a graphics card will improve your performance dramatically when dealing with CAD software.

When shopping for a video card, again, you must consider what it is that you are doing with your software. Using my previous example, if you are just a 2D Drafting and Annotation guy who uses AutoCAD for 2D drawings, then you do not need a beefy video card. However, I do still recommend that you get at least a low-range video card. A video card with 256 or 512 MB of RAM would be more than enough for somebody who’s only using 2D functions in AutoCAD. Now, if you are a person who uses 2D Modeling in AutoCAD, then exports that file into Revit to draw up the 3D model and then exports that 3D Model into 3DS Max to create an environment around that 3D Model, then you will want to get a beefier video with 512 MB or more of RAM on it.

When it comes to manufacturers, Autodesk’s software is designed around NVidia graphics cards. This does NOT mean that ATI cards will not work with Autodesk products. For CAD programs, it’s usually recommended to purchase the NVidia Quadro series of cards. This is not required, but you get better performance out of the Quadro cards than you would out of an Nvidia GeForce card. GeForce cards will run the software perfectly fine, but Quadro cards will give you the best performance. Keep in mind that the Quadro series will cost a bit more money. When you’re looking at ATI cards, you will probably want to go with ATI’s Radeon HD series of cards. Whatever product line/manufacturer you choose, just keep in mind that you will want to get a video card with at least 512 MB of RAM. If you’re not doing much 3D modeling or are on a strict budget, then you can probably get by with a 256 MB card.

Before purchasing any video cards, ALWAYS check hardware compatibility so you can make sure that the card you’re looking to purchase will work with your software. You can find a database of Certified Graphics Cards for CAD products on Autodesk’s website. The easiest way to find it is to go to and use the search function at the top-right of the page to look for “productname certified hardware” where productname is just the name of the specific product that you have an inquiry about such as AutoCAD or 3DS Max.

Hard Drives

Hard drives hold most of the data on your computer. Hard Drives also house your Operating System files as well as the files that your programs need in order to run. Hard Drives are an important part of a computer. When dealing with CAD software, you will always want a good-sized hard drive. Programs like Revit, AutoCAD, Inventor, etc. all can generate very large project files upwards of hundreds of MB. If you’re doing a lot of these kinds of projects, then your hard drive can fill up on data rather quickly. Not to mention, the programs usually take several gigs of data just to install themselves.

When purchasing a hard drive, there are two main things you want to look for; space and speed. Nowadays, it’s easy to find hard drives that hold 1-2 Terabytes of data. A terabyte is approximately 1,000 Gigabytes. A Gigabyte is approximately 1,000 Megabytes and so on. For a dedicated CAD machine, you will probably want a hard drive with at least 320 GB of space or more. Again, as your project files get larger and larger, you will find yourself running out of hard drive space rather quickly. Considering how inexpensive hard drives are these days, lots of people just get 1 Terabyte drives because the value is so good. 1 Terabyte is more than enough space for you to run a CAD machine on.

The speed of a hard drive is very important. You always want to install your Operating System and your programs on a fast drive. This allows for programs to open up quicker and run quicker. The standard for most 3.5” internal hard drives is 7200 RPM. 7200 RPM is a great speed that is capable of running tons of programs as well as an Operating System with pretty fast speeds. You can find hard drives that are 10,000+ RPM, but they will cost you quite a bit more money. However, they are very fast. Your programs will open and operate very quickly; much faster than a 7200 RPM. Keep in mind that drives that go beyond 7200 RPM usually don’t have as much data storage. I haven’t seen a drive beyond 7200 RPM that has more than 800 GB of space. If you’re looking at getting a really fast drive, I recommend getting a second drive to store project files and data on so you don’t run out of space.

There are new drives on the market called Solid State Drives. These drives utilize a new hard drive technology that allows for the drive to reach read/write speeds never-before seen in consumer hard drives. The downside is small disc space, a high price tag, and technology-specific issues that may still need to be worked out. I have not used solid state drives yet so I cannot provide a direction on them. If you have the money, then it might be worth checking into. I recommend doing a lot of research if you’re thinking of purchasing a solid state drive.


Hardware is a critical component for any computer. For CAD software, you will want to create a computer that is more catered to your needs. This does not mean that you have to go and make a completely customized machine. You can get a more-than capable computer from many of the main manufacturers such as Dell, HP, Gateway, etc. This post will hopefully give you a list of things to look for when purchasing your next CAD machine. The most important thing is to get a computer that meets your financial needs but can still run all your programs smoothly and error-free.

Author: Mark Phillip

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