Zwift on PC: The Ultimate Guide to Running Zwift at Its Very Best

Whilst many people happily run Zwift on their mobile phone, tablet, AppleTV, or laptop, there are also lots of Zwifters using PCs who may be considering upgrades or building/buying something new to improve their experience. This article is not intended to provide a comparison between the pros and cons of the various platforms, but rather offer advice to those who wish to run Zwift at its very best – that is to say, on a PC at the highest detail level and at a high frame rate of 60fps or more.

There are a lot of misconceptions about the amount of processing power needed that I will try to address – the main ones being that great Zwift performance is all about the graphics card (not strictly true), that CPU doesn’t matter (not true) and that you need an ‘expensive gaming rig’ (definitely not true).

Warning: if you’re already content with a lower level of detail and/or a low frame rate, this article is not for you! A better-looking, smoother Zwift will not make you faster (unless it gets you on the bike more often). It’s just nicer.

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It’s important to note that almost all of what follows is NOT particularly good advice for PC gaming in general, because Zwift has its own bottlenecks and quirks and there are hugely diminishing returns beyond a certain point of investment. This guide is aimed at people who want to use their PC solely or mainly for Zwift and want great results without wasting money unnecessarily. At current UK prices, it’s easy to build a fantastic Zwift PC for under £400.

TL;DR – Key components to buy for best performance/value ratio (February 2020):

• You need a CPU with high clock speed and strong single-thread performance. More cores are essentially irrelevant, so don’t waste your money. Whilst AMD Ryzen CPUs are excellent value and offer a fantastic future upgrade path, in general Intel CPUs are better suited to Zwift. Good examples: Intel Core i3-9100F, or Core i5-9400F if streaming or multitasking is your thing.
• Buy an Nvidia graphics card of series 10xx or newer, with 4GB of VRAM or greater. Don’t go too far though because you’ll see the same bottlenecks no matter what, so don’t waste your money. I’m not even convinced Zwift uses more than 4GB. Good examples: Nvidia GTX 1660, GTX 1650 Super, or GTX 1060 6GB.
• Unless you are dead set on a big 4K TV, look to buy a Freesync monitor with a wide adaptive sync range; ideally enough to allow for Low Framerate Compensation (LFC). Good examples: Pixio PX275h (branded ElectriQ in the UK) or virtually any 144Hz gaming monitor with DisplayPort input (important!)
• 8GB of system RAM is plenty, and adding it in dual channel configuration (i.e. two sticks) is best practice. More capacity won’t improve anything, so don’t waste your money. Good example: 2 x 4GB 2400Mhz DDR4.
• Zwift can take a while to update and load worlds, so have your system running on an SSD. If it’s just for installing Windows and running Zwift, even a 120GB SSD is easily big enough.
• Note: AMD graphics cards don’t perform as well in Zwift, so they should generally be avoided.

Settings

Before we move onto specifications, it’s important to know that beyond manually tweaking the configuration files (there’s a brilliant guide here on Zwiftinsider.com) there are only two graphics settings in Zwift and only one is determined by the user. The actual detail levels – depth of field, lighting/shadow effects, and environmental elements such as water effects and wildlife seen – are chosen automatically by Zwift HQ. They determine what you see based on your computer’s graphical ability. For computers using integrated graphics (i.e. no dedicated/discrete graphics card), you will always see the Basic detail profile. Almost exactly the same as phones, tablets, and Apple TV.

This increases through Medium and High up to Ultra for mid-range graphics cards and above. HQ identify and account for every graphics card on the market and decide on a profile for it, hence the reason why some people with newly released graphics cards sometimes see less detail than they are expecting. It’s worth noting that whilst AMD graphics cards offer really good value for normal gaming, they perform relatively poorly in Zwift because Zwift uses the OpenGL API, and AMD’s OpenGL drivers are much less optimized than those offered by Nvidia.

The only graphics option Zwifters have control over is the display resolution of the game, which is accessed via the in-game settings menu. This ranges from 576p to 2160p (4K). Rather unhelpfully, these options are also named Basic, Ultra, etc so it’s understandable why some people get confused. Selecting the higher options and hoping to maintain 60fps+ will obviously require a stronger graphics card, but it won’t increase what you see – that’s based on the automatically-set profile set by HQ. Higher-resolution options are just increasingly sharper and cleaner. Note that you’re not limited to the resolution of your display – it’s possible to choose a higher setting for a nice anti-aliasing effect – just be aware that it will also have a performance impact.

To recap, in order to see the Ultra PROFILE you will simply need any decent Nvidia graphics card from the last five years or so. If you want to run the High RESOLUTION (1080p) or above nicely, expect the demand on your graphics card to increase.

The Problem

But here’s where it gets more complicated. In a solo ride, in a relatively quiet area of Watopia, any decent graphics card will be able to do Ultra profile, 1080p resolution at 60fps without any bother at all. However in a busy group ride, or in areas like the most common spawn point in New York (at the bottom of a hill!), you will probably find that your frame rate tanks. The impact can vary in significance, from just losing a few frames right down to making Zwift an expensive slideshow.

The unfortunate truth is that as things stand this behaviour cannot be completely avoided, almost no matter what your computer specs are. Through my own testing and observing the many posts, logs and diagnosis on the various Zwift groups and forums over the past couple of years I’m convinced that all PC builds drop frames in this way. This even applies to those with £500+ graphics cards and £500+ CPUs which is patently ridiculous when you consider what these extremely high-end components can achieve! Zwift doesn’t look bad, but it’s miles behind the visuals of modern games. There’s simply no logical reason why you should need to spend so much on a PC to run Zwift well, but I am not a programmer so I cannot say why this is.

What certainly seems to help is not a stronger graphics card, but a CPU with better single-thread performance. This is almost always an Intel CPU. Whilst AMD’s Ryzen series of CPUs are a better value in general and provide a much better upgrade path – because all three generations released to date can normally be installed in the same motherboard – up until the most recent 3000 series CPUs, their single-thread performance trailed behind the Intel equivalents. Additionally, some people have experienced graphical anomalies with the 3000 series Ryzen CPUs, so at present it’s hard to recommend them for Zwift.

Because Zwift doesn’t appear to benefit in any way from extra cores, there’s little point going above a quad core. This combination means the Intel Core i3-9100F is a perfect option. It’s laughably cheap and should do the job nicely if Zwift is all you’ll be doing. If you also want to stream, multitask, encode video or use the PC for other things, a step up to the six-core i5-9400F is a good idea. I’m a big fan of Ryzen CPUs and virtually everything you’ll see online will recommend them for builds, but for Zwift it’s easier to just stick with Intel.

With analysis courtesy of the excellent Zwiftalizer.com, here are two examples of solo ride warmups in Watopia followed by races in other worlds:

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In both cases the frame rate is perfect until I join the race, when the frame rate drops hugely until the field becomes suitably stretched. I believe it’s down to how Zwift is programmed, and potentially due to how slowly data gets to us from their servers. The user’s computer must visualise the live positions, speeds and drafting physics of potentially thousands of other riders (although only the nearest 100 riders are actually rendered on screen) and it appears lots of these calculations are done at the client end. Graphics cards are severely under-utilised, and the frame rate drops.

It may seem counterintuitive but it’s preferable for a graphics card to be working at a high utilisation in games, that way you’re getting the maximum out of it. Utilisation being low means it’s being stopped from working to its best by some other aspect of the system – a bottleneck. Or to put it the other way around, if utilisation was pegged at 100% and frames were being dropped it would be easy to see that a stronger graphics card would improve performance, but that’s not the case in Zwift. Likewise, reducing the resolution setting should see a substantial improvement in frame rate in the most problematic situations but this is rarely the case. It’s further proof that you needn’t spend more and more on a graphics card, because it’s clear that’s not where the major bottleneck is.

Unless this behaviour changes – and bear in mind Zwift HQ openly state that their focus is low-end/low power platforms due to user base demographics – then spending more and more money on processing power hoping to eliminate the frame rate drops isn’t really an answer. It can certainly help of course, as can overclocking to push your components more. But none of this gets away from the fundamental issue which is out of our control.

Mitigation

So yep, you could buy an RTX 2080Ti and an i9-9900KS and overclock everything within an inch of its life. Or you could buy/keep good quality mid-range components and accept that the performance will always suffer in certain circumstances.

If you want to display Zwift on a big TV this is where the story ends. But if you want to mitigate the drops, that’s where adaptive sync comes in very handy. Fortunately, Nvidia made this much easier to obtain in early 2019 by announcing Freesync support for its 10xx series graphics cards and newer. Previously you needed to buy an expensive GSync monitor but this is no longer the case. Adaptive sync allows you to simply smooth out the frame rate drops at the other end of your system. I realise lots of Zwifters like to use a TV to display the game, but as with normal fixed refresh rate monitors that normally means you can’t use adaptive sync. With a normal TV or monitor, you are stuck with two options for Zwift:

1. Vsync on: brilliantly smooth when your computer can maintain 60fps*, but causes stuttering and drops to 30fps** when it cannot.
2. Vsync off: your computer just outputs whatever it can, causing screen tearing at everything other than exactly 60fps*.

*your display’s refresh rate
**half of your display’s refresh rate

Adaptive Sync

With adaptive sync, a display changes refresh rate in real-time to match your frame rate – smoothing out all the fluctuations within a range determined as part of the monitor’s specifications. For example, the specs of my monitor show the Freesync range is 48-75Hz so whenever I’m in that frame rate range I don’t see any tearing or stuttering. It’s perfect for a game ‘on rails’ like Zwift. Ideally you want enough adaptive sync range to allow for every eventuality you will encounter. On 144Hz gaming monitors you’re basically covered no matter what, because even below the adaptive sync range, Low Framerate Compensation (LFC) kicks in to avoid stuttering.

Whilst Freesync now works with Nvidia graphics cards, bear in mind it’s only available over DisplayPort (it won’t work over HDMI) and with the exception of the few officially-certified models on the market, you won’t know if any particular monitor will work perfectly until you try it. Check reviews or Reddit and the likes to see how other people got on, you’ll normally find someone somewhere has tried it and reported back.

There have been some Freesync TVs on the market for the last couple of years but aside from the newest LG OLED models, they require an AMD graphics card which as mentioned don’t perform very well in Zwift. So whilst it is feasible to obtain adaptive sync on a very big screen this way, you’d essentially be knowingly buying a component that doesn’t work very well, in order to mitigate it with another. Otherwise a big TV is great, but you should be aware that you’ll need a stronger CPU to ensure your frame rate stays at or around 60fps as often as possible.

Here’s an example of a solo ride around the newly refreshed Richmond, with lots of riders nearby at all times:

Thanks to adaptive sync, my experience was great because my frame rate stayed within the adaptive sync range of my monitor for almost the entire time no matter what was going on, with just a couple of very brief dips below 48fps which weren’t noticeable. No tearing, no stutter, just perfectly smooth Zwifting. See also the graphs from my races above; once my frame rate was back above 48fps everything was back to being great.

Summary

• As things stand you can’t really avoid frame rate drops on Zwift.
• How severe they are is dependent on your components, but don’t expect them to disappear completely.
• You DO NOT need to spend mega money on a gaming PC to get a great experience in Zwift, so don’t!
• Spend your money in the right places if you want to focus on mitigating the issues.
• This is much easier with an adaptive sync monitor but is also possible with a select number of TVs.

Bonus addendum: Doing all this on a tighter budget

Buy an ex-office SFF desktop PC with a CPU like a i5-3470 or similar. There are tons available on the likes of eBay. Install a GTX 1650 low profile which fits, runs from the PCIe slot alone and can normally be accommodated by the power supply in this class of computer. Ensure you have good ventilation and be sure to change the Nvidia power management mode to ‘Prefer maximum performance’. Upgrade the DDR3 RAM to 8GB, it’s dirt cheap on eBay or CeX in the UK. Whack in an SSD and install Windows from a USB stick. You should be able to achieve 60fps in Ultra detail at 1080p in normal circumstances for under £250. All the same principles and caveats above still apply though.

Good Resources

• https://www.cpubenchmark.net/singleThread.html – to compare CPU single thread performance – higher is better
• https://browser.geekbench.com/processor-benchmarks – an alternative way of comparing CPUs
• https://www.techpowerup.com/gpu-specs/?mfgr=NVIDIA&sort=generation – to compare Nvidia graphics cards
• https://www.amd.com/en/products/freesync-monitors – to find a monitor’s adaptive sync range and filter by size etc
• https://zwiftinsider.com/config-file-tweaks/ – if you want to mess about with the graphical details settings manually
• https://pcpartpicker.com/ – for putting together proposed PC builds, checking compatibility and comparing prices

Acknowledgments

Thanks to J.Levie, M.Hanney, S.Louvet and M.Wozniak for their input and help when compiling this article. Ride On!