For those looking for a quick answer on how to do this, here it is in a nutshell. Everyone I've talked to recently such as Autodesk, other technology firms and IT professionals are saying to make the jump to Windows 7 64bit OS. It is of course up to you to verify that if you are running older hardware and software to ensure they will work on Windows 7 64bit OS. If you bought a new computer in the last year or two, there is a really good chance your hardware will be fine leaving you to ensure just software runs fine.
As for choosing the right hardware, more is usually better - usually. Ask yourself, what do I work with on a day to day basis? Simple AutoCAD drawings that average in size at approximately 1-5 megabytes? Do I work with moderately sized Revit files in the 50-75 megabyte range or really big ones over 150 megabytes? Do I work on large scenes in 3ds MAX with millions of polygons and file sizes pushing the 200 megabyte range?
Each of you may have a slightly different answer which means I can't really give a one size fits all answer to hardware. I can help you understand what is what and where the different parts of the computer will help.
- CPU: This part will help process calculations that process math.The more CPUs you have and the faster they can run, the more that can be processed - provided your software is written to take advantage of them. AutoCAD can take a small advantage from a multiple core CPU. Revit will only take advantage of multiple CPUs if you render. 3ds MAX Design will take advantage of multiple CPUs for math related tasks as well as rendering.
- HD: There are three things to look at with a HD. Type, speed and size. Traditional HD's using a disk will be the least expensive option but the newer SSD HD's will not be. Traditional HD's offer larger a large storage space, SSD are catching up but not quite there yet. Traditional HD's offer varying speed which affect the rate at which data can be accessed - look for something at least 7200 RPMs or above. For SSD, data is access nearly instantaneously. Pick your poison!
- RAM: In the past, RAM wasn't so critical. Now, if you are trying to work with medium to large sized files like I mentioned, RAM will make or break your day. The bigger the file you are trying to open is, the more RAM you should have. I've heard on numerous occasions by IT professionals that you should strive for a minimum of 2GBs RAM per CPU Core on a 32bit OS and 4 GBs RAM per CPU Core on a 64bit OS. There is obviously a limit for your budget and perhaps how much your motherboard can hold, but that's a pretty good rule of thumb to follow if possible.
- Graphics Card: This is what helps your computer display information in your drawing viewport on your screen. For using Autodesk products, try and stay away from gaming cards as they typically are not certified or supported. The better the card and the more on board memory it has, the better things can look and perform in the viewport. Ever try to run 3D orbit on a model to have it skip or jump as it is spun? Most likely you had a card that wasn't up to the task. If you are trying to preview lighting effects, materials in a realistic shade mode or have a lot of data to display, the better the card, the smoother things will go.
Here is a link to some Revit white papers, one of which is called the Revit Model Performance Technical Note. This has detailed recommendations regarding OS, CPU, RAM, HD, Network and other items in addition to keeping your Revit model running smoothly. In the version released for working with Revit 2010, they don't get into graphics cards in great detail so I've been recommending people take a look at the AutoCAD or 3ds MAX certified graphics cards (links to follow).
Revit White Papers: Model Performance Technical Note
Here is the link to AutoCAD Certified Hardware where you can look to see if a card you have in mind is certified or get the latest info to make sure AutoCAD runs smoothly with your graphics card. You can combine the Revit white paper above with a card in this list to ensure compatibility on into the future. Please, when choosing a card, be sure to select one that are Certified, Supported AND Recommended!
AutoCAD Certified Hardware
With 3ds MAX Design, Autodesk gets even more detailed in helping you choose hardware. This goes well beyond showing you which graphics cards are Certified like with AutoCAD. They go so far as to test specific configurations from major manufacturers that are currently available for Graphics Cards, Workstations/Laptops and Tablets. Since 3ds MAX Design is likely to place the most burden on your system, choosing products from the list in here will likely provide you with a system that will meet your needs for a long time to come.
3ds MAX Design Certified Hardware
Then of course there are specific requirements for running Autodesk Inventor and the other products it works with. Please check out the following link for a well put together site to help you choose the correct setup for working with Inventor.
Inventor Hardware Website