Revit Hardware Guide

Workstations for Revit need not be obscenely expensive, you just need to know what part of the system really matters or more so, what parts you can cut if you’re on a budget. Years of experience has shown the the IT department usually hears Revit and think “modelling spec” and configure high end rendering/CAD systems or at the other end of the spectrum, they purchase based on the Autodesk minimum recommended hardware, both scenarios are rather lacklustre when it comes to driving Revit on a day to day basis.

Here are a list of my recommendations for 2014 based on experience building Revit machines and referencing articles such as Autodesk’s Model Performance Technical Note; even if you’re not building yourself, you can compare these recommendations with specifications from major manufacturers.

Before I start, this page is subject to change and is by no means intended to be set in stone machine specs, but rather a guide to get you started if you’re not sure where to begin.

The CPU

ivy-bridge-b3In 2020, Revit remains mostly only optimised for running on a single thread. That means unless you’re rendering, CPUs that have been designed for multi-threaded workloads will never be fully utilised and are may not be the wisest investment from a hardware perspective if operating Revit or even AutoCAD is your bread and butter.

According to Autodesk, multi-threaded components of Revit are:
  • Vector printing
  • 2D Vector Export such as DWG and DWF
  • Mental Ray Rendering
  • Wall Join representation in plan and section views.
  • Loading elements into memory. Reduces view open times when elements are displayed for the first time in a session.
  • Parallel computation of silhouette edges (outlines of a curved surfaces) used when navigating perspective 3D views.
  • Translation of high level graphical representation of model elements and annotations into display lists optimized for given graphics card. Engaged when opening views or changing view properties.
  • File Open and Save
  • Point Cloud Data Display

So as you can see, for the average Revit user, the only advantages of the best of the best multi threaded chip are really with file open and save operations and vector printing which is only a small portion of the daily grind.

So where do we start? Firstly lets compare CPUs aimed at multi-threaded performance vs. CPUs that have better single threaded performance. The links below compare just this; the results are based on synthetic benchmarks so they should be taken with a grain of salt, but they’re still a great reference point to compare the capabilities of various CPUs.

Passmark – Multi Thread Benchmarks
Passmark – Single Thread Benchmarks

As you can see, the CPUs that take out top spot on each chart are different between single and multi thread. The CPUs that are king at multi threaded workloads tend to fall behind in single threaded workloads. Unless you’re doing all your rendering on your own PC, maybe look at spending your money somewhere else in your system if you’re purely using Revit to for modelling. If your business prefers to run Xeon based workstations, then the chips that score higher in single threaded performance should be the preference, otherwise AMD Ryzen 7 or Intel i7 based systems are the way to go. 

A Quick Note on CPU Cache

The Autodek Performance Technical note states that there are substantial performance benefits to using CPUs with L2 caches of 2mb or more. This is a little misleading when looking at today’s hardware, as Intel has not had large L2 caches since the Core 2 days. With the i series chips, Intel has moved to using larger L3 cache and utilise a smaller L2 cache.

The principle of caches is rather simple. They buffer data as close as possible to the processing core(s) in order to avoid the CPU having to access the data from more distant, slower memory sources. Today’s desktop platform cache hierarchies consist of three cache levels before reaching system memory access. The second and especially the third levels aren’t just for data buffering. Their purpose is also to prevent choking the CPU bus with unnecessary data exchange traffic between cores.

The current range of Kaby Lake i7 chips have 64kb of L1 cache per core,  256kb of L2 cache per core and for the desktop processors 2MB or more of L3 cache per core depending on the chip you’re looking at.

The new AMD Ryzen CPUs are solid contenders for use in Revit machine, they have 64kb of L1 cache per core, 512kb of L2 cache per core and 2MB of L3 cache per core.

If you’re looking for the absolutely best CPU you can get for Revit modelling, there is a lot to choose from in 2020, there are a lot of great offerings from both AMD and Intel that will perform well, both companies have been closing the gap in laptop performance as well, for every day work even laptop CPUs in the 15w TDP range will run Revit buttery smooth. If you are going to be creating a lot of rendered images or video though, laptop chips tend to still be weaker than their desktop counterparts in multi-threaded applications, this is due to the power envelope the chips need to work within and to keep the system running cool the CPU clocks need to reduce to keep things in check (known as throttling). 

Something of note though, if you’re considering upgrading a machine that is a few years old, the performance increases in the newer chips may not be worth the investment. For example the desktop i7 7700k is only beaten by the much newer i7 9700k by 4% in single thread performance.

The main difference seen in hardware has been the increase in core counts, introduction of multi-threading to the lower end Intel CPUs and a well those low end CPUs now catching up with the high end in performance. A stand out example of this is sitting within that 4% performance margin beween the 7th and 9th generation i7 parts is the i5 9600. In the past many would overlook the i5 and i3 parts for use with applications such as Revit but these days, the i5 is more than enough which can significantly decrease the cost to invest in hardware!

Meanwhile the AMD Ryzen CPUs have completely turned around from previous generations and are perfect for both Revit usage with high single core performance but also have outstanding multi-thread performance. There is nothing to lose by investing in an AMD system.

The Graphics Card

XFX280X_678x452Unlike other engineering based software packages, Revit is not optimised for OpenGL, it is optimised to run under DirectX which is where gaming cards shine and workstation cards fall behind. This means that cheaper cards marketed toward the gaming crowd are more suited than OpenGL optimised workstation cards such as the Nvidia Quadro or AMD Firepro. Workstation cards simply have firmware that is optimised for OpenGL. In the early days OpenGL was better and faster than Direct3D but now there is little difference. Gaming cards only support a very limited set of OpenGL, hence they don’t run it very well. Historically workstation graphics cards were the card of choice with high end CAD machines as they could drive multiple monitors where non workstation cards either struggled or were limited to a single screen, but these days this is simply not the case. The price premium simply isn’t justifiable for a Revit workstation.

A mid to high end gaming graphics card will result in buttery smooth on screen navigation and overall fantastic user experience. Look for GPUs with fast memory and high GPU frequencies.

Great options for graphics cards sit in the mid range onward which retail for around the $400-500 mark depending on brand and model. If you’re running a previous generation mid range to top tier GPU though, there is no real reason to upgrade.

Memory

xms3_1x_angled_316gb would be the minimum recommendation for medium sized projects, this is more so true for MEP than our architecture and structure counterparts. Architecture and structure usually only have their own models loaded and use Navisworks to coordinate between other models when required. Generally MEP users load not only their own model within Revit but structure and architecture links as well. So with that in mind you don’t just need the memory your model, but all the linked models as well a project. From experience, a roughly 10,000m² building can quickly turn into your model and 1.5gb of linked models. As always with Revit, the faster the better. RAM is usually clocked around  2133mhz – 3200mhz these days, buy the fastest RAM your budget will allow.

Buying From a Big Brand

As a side note, pay attention to what you’re buying from the big brands. They often install lower spec’d, cheaper RAM. If it isn’t clear on the website or in store the speed of the RAM in the computer you’re looking to purchase, give the customer service team a call. If the company you’re buying from still offers RAM upgrades, think twice if it is lower spec’d. It may be cheaper to buy your upgrade from a computer store and install it yourself.

Primary Hard Disk

StorageReview-Samsung-SSD-840-ProThe cost of SSD drives have tumbled over the last few years and 1tb drives seem to be the sweet spot. If you can’t justify the cost of a 1tb SSD drive, consider purchasing a 256 – 512gb SSD with a secondary drive that you can move your user profile and other data to. The user profile folder (i.e. My Documents and other user data) is usually the largest space hog and listening to your MP3 library or viewing the happy snaps of your most recent holiday does not benefit from SSD speeds, so it makes sense to move it onto a conventional hard drive.

Monitors

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Dual monitors have been mainstream for a number of years now, however personally I now run a single 34″ UWQHD 21:9 screen which runs at 3440 x 1440 and is 1.5x the width of  regular 16:9 screen.

Revit fits wonderfully on the single screen with both properties and project browser windows docked to the left and right respectively. Something to be mindful of if you move to higher resolution screens is that you may need to upgrade your video card and potentially the cables as well to be able to reliably handle the resolution. Most graphics cards can handle these resolutions without issue, but you may be caught out with the cables.

Display port is the cable of choice as it will handle the high resolutions, multiple screens and high refresh rates without issue.

These days, I am personally using a USB 3.2 Type C cable which drives the display, with the display having a built in USB 3 hub with type-a connectors I’ve been able to simplify the nest of cables hooked up to my system.

Just remember that when you’re dealing with USB-C connections, USB 3.x on a type-c connector is not the same as Thunderbolt 3, with USB 3.2 topping out at 10gbps and Thunderbolt 3 reaching 40gbps allowing Thunderbolt to drive more high resolution screens at higher frame rates than USB 3.2.

Final Thoughts

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It is always a good idea to buy a step or two below the flagship products offered as you pay a price premium for getting the best of the best. This is usually more so with CPUs and GPUs for example, the flagship Nvidia 1080ti graphics card is $300 more expensive than the Nvidia 1080 and double the price of the Nvidia 1070 but for that 40% increase in cost over the 1080 or 95% increase over the 1070, you only get barely a 27% increase in performance over the the 1080 or 56% over the 1070.

If you’re building your Revit machine yourself or having your local computer store build it for invest in an 80+ platinum certified power supply with modular cabling which will provide cost savings operating your machine over time, modular cabling will also clear up the case of unwanted extra cabling and better airflow.

If you chose to go down the Intel path and have no intentions of overclocking your machine, you can save a few dollars by buying the i7 7700 rather than the 7700k and you can opt for cheaper motherboards based around the H270 chipset rather than the Z270 based boards.

Finally, if building myself I would personally round out my system with a Bitfenix Prodigy case which uses a Mini ITX motherboard. I don’t need my machine to take up more space than it needs and it’s portable if I need to move around or temporarily setup in a site office. Ultimately the choice of case is up to you, just make sure all your components fit and that there is adequate air flow to keep all the components cool.

Building yourself, depending on how you spec the machine expect to spend between $1300 – 2000+ for the computer without any peripherals. With the recommendations made above, I came to a touch over $1800 using today’s prices which includes a 512gb SSD and an 80+ platinum PSU. You can however easily drop to below $1300 if you swap out the SSD for a conventional hard drive, drop the 80+ platinum to 80+ silver or bronze and drop the video card to either an Nvidia GTX 1060 or AMD RX 570 for what would still be a very capable machine.

If you’re looking at one of the big manufacturer’s, consider the Dell 3000 series (i7 only), HP Z2 Mini (i7, Xeon E3) or Z240 (Xeon E3) or if you’re feeling adventurous, an Alienware Aurora (i7 only) which is far better spec’d and cheaper than both the Dell and HP.