Testing AMD's new Radeon Anti-Lag Feature

Alongside the release of AMD'southward new Radeon RX 5700 Navi GPUs, the company rolled out two new features in their Radeon driver suite. Last calendar week we looked at Radeon Image Sharpening which directly targets Nvidia'south DLSS, and today we're back to cheque out the second feature, Radeon Anti-Lag.

The basic goal of Radeon Anti-Lag is to reduce input lag while gaming. Input lag is the delay betwixt when y'all brand an input, like a mouse click or central printing, and when the action takes place on your display. For fast-paced competitive games, especially shooters like CS Go, Overwatch or Fortnite, it's key to take the lowest input lag possible so you tin can spot your enemies, target them with your weapon, and shoot them as quickly and smoothly as possible.

The basic goal of Radeon Anti-Lag is to reduce input lag while gaming.

Input lag is a combination of many factors. Some involve your peripheral hardware, like your monitor, mouse and keyboard. Some involve how fast your CPU and GPU are at processing frames. But Radeon Anti-Lag is focused on reducing lag at the commuter phase. We think AMD has done a great job at explaining this in improve particular, so nosotros'll quote them here...

"Games produce frames of blitheness by pairing work washed on the CPU with work done on the GPU. The CPU begins its piece of work first, and information technology feeds piece of work to the GPU as information technology works its way through a frame. In most apply cases, the GPU workload is the primary performance constraint. We phone call this a GPU-limited scenario.

In such scenarios, games perform the CPU work at to the lowest degree i frame alee of the GPU work, resulting in two frames of latency in total. The delay between the click of the mouse – registered during the CPU work for the frame – and the response on the screen – produced by the GPU – can aggrandize to comprehend the time required for the GPU to process two full frames or more. At 60 FPS that delay is 33.3 milliseconds (2 frames at 16.7ms each) or more

In such cases, Radeon Anti-Lag dynamically improves the pacing of the CPU piece of work, assuasive the GPU work to overlap a significant portion of the GPU work, then the CPU doesn't get likewise far alee of the GPU. Every bit a result, Radeon Anti-Lag tin, in theory shrink input lag by almost a full frame – about 16.7ms at lx FPS – restoring responsiveness to your game. The impact is quicker response times and a more direct connection between your actions and the results shown on screen"

Radeon Anti-Lag can reduce input lag by upwardly to a full frame, according to AMD, when mostly GPU limited. And we'll get into the implications of this when nosotros put up some cute blue graphs. For now, there's a few other things to discuss.

One is that Radeon Anti-Lag works on any "recent" AMD GPU or APU, so not just new Navi GPUs. However it only works in DirectX xi titles, unless you accept a Navi GPU in which case it likewise works for DirectX nine. No AMD GPU supports this engineering in DirectX 12, Vulkan or OpenGL. A lot of popular competitive games have DX11 modes, merely naturally as more games begin to use newer APIs, Radeon Anti-Lag will need to evolve to back up them as well.

There are three ways to enable Anti-Lag: in the game profile settings, in the Radeon Overlay -- that's the method we used the most -- and using a new Alt-50 global shortcut. In all three cases it's but a simple toggle and gets to work right away, even in game.

For testing, nosotros decided to measure the unabridged click-to-response input lag using the same methodology as we practice for our monitor reviews. We use a photodetector on the screen, every bit well as a mouse input, both hooked upwards direct to an oscilloscope. Using this method we can record the precise time we ask a game to do something (like shooting a weapon) and the precise fourth dimension this action is shown on screen. We await Radeon Anti-Lag to take the lowest response time numbers over a xx sample average for each test.

Nosotros chose fast hardware for testing. On the graphics front nosotros used the new Radeon RX 5700 XT, paired with Intel's Core i9-9900K which remains the fastest CPU for gaming. Nosotros also used the fastest display we have on mitt: Pixio'due south brand new PX5 Hayabusa -- review coming soon -- which is a 1080p 240Hz display with 0.6ms response times.

Game Tests

We've tested three different modes: vsync on, vsync off, and FreeSync on, with Radeon Anti-Lag both enabled and disabled. Doing input lag testing takes a lot of time then nosotros've express the number of games compared to a regular GPU review but the ones we have included should cover most scenarios.

Allow'south offset with Rainbow 6 Siege, a game that generally has very low input latency. The game runs well on about hardware and nosotros were pushing higher up 200 FPS without much sweat. High frame rates take a significant touch in reducing input latency. Across the lath we are pretty much in that 17 to 22ms of input latency zone, which is lightning quick.

Radeon Anti-Lag did produce consistently faster results on 2 of the three examination conditions. For Vsync off we shaved off two.3ms, and for FreeSync we shaved off about 2ms. At that place was no divergence for Vsync on gaming, not that we'd recommend using Vsync for any input lag sensitive games. Given the game was running at around 220 FPS in this test, it seems Radeon Anti-Lag shaved off around half a frame's worth of latency, with each frame lasting 4.5ms at this frame rate.

A two.3ms reduction or thirteen% improvement to input latency doesn't sound all that impressive, but there are a few things to proceed in mind. AMD'due south claim is that we can await upwards to around a unmarried frame of latency comeback, however given we're gaming at such a high frame rate to brainstorm with, that 1 frame isn't really all that much latency. AMD too says Anti-Lag works best when games are GPU limited, and when running at over 200 FPS by and large the CPU is already doing quite a fleck of the work.

For comparison purposes nosotros've likewise got results from a GeForce RTX 2070 playing the game at the same frame rate, around the 220 FPS mark. Input latency was a piffling college in full general, and so Anti-Lag does provide some benefit, however nosotros're but talking about a 4ms difference. Information technology's non a significant upshot.

Next up we take Fortnite, a game that's going to run really well on most hardware. Even playing the game on the Ballsy preset at 1080p we were achieving ~170 FPS during testing. Radeon Anti-Lag was consistently faster, in the range of 2 to iv milliseconds better. Just with frames coming in every v.9ms or so, nosotros simply aren't going to get much more of a reduction in input latency.

In fact, AMD says that the benefits of Radeon Anti-Lag are most pronounced when gaming between sixty and 90 FPS and in the 2 games nosotros've tested then far, fifty-fifty with maximum quality settings we were more than doubling that sort of frame charge per unit. This is pretty important to know and volition cistron in our conclusion.

Simply earlier that nosotros wanted to examination a game where we knew would hit AMD's sweet spot zone: Metro Exodus. In this title we prepare the game to the Extreme preset and were striking around 75 FPS in our test area. As expected, the advantages to Radeon Anti-Lag were more obvious here. We saw a reduction in input lag of between 4.6 and 10.6 ms depending on the sync method used, with the latter number showing that we're getting virtually a total frame reduction in Metro Exodus. At these frame rates, achieving eighteen precent better performance, or a 15% reduction in input lag, is a stronger result.

The second game where we found interesting results was Battlefield V. This game has a manner called "hereafter frame rendering," which you tin can switch off for better latency, co-ordinate to the in-game information. For testing we set that mode to off as went about comparing Anti-Lag on and off. Equally it turns out, Anti-Lag has adjacent to no effect when this mode is already enabled. So information technology seems that at least for this title running in its DX11 style, developer EA Die had already figured out how to minimize input latency and implemented their own toggle. So that'south kinda great.

Merely why isn't this just enabled by default? Is there any downside?

Now you may exist wondering, if Radeon Anti-Lag improves input lag in games, why isn't this simply enabled by default? Is at that place any downside? And the respond to that is yes, but it's not a pregnant downside.

We tested a number of games with Radeon Anti-Lag on and off to see the operation affect. Several of these had a negligible functioning drop: i FPS in Metro Exodus, three FPS in Rainbow 6 Siege, less than 1 FPS in Resident Evil 2, and no difference in Battleground V, all looking at boilerplate frame rates. The impact to i% lows could be anywhere from delivering a consistent improvement, to lowering functioning.

However there were also some titles were the performance impact was more substantial. In Fortnite we saw a half dozen% drop to performance, or 7 FPS, looking at average framerates with an even larger driblet to 1% lows. The hit was fifty-fifty larger in Hitman 2 at over 11 percent. AMD says it isn't unusual to see a performance impact in some titles simply not others, so your mileage will vary. Certainly some times y'all can enable Anti-Lag without worrying, just others the hit will be noticeable.

Bottom Line

It's clear that Radeon Anti-Lag does what information technology sets out to do. In GPU express scenarios, it delivers about a i-frame improvement to input lag, and works all-time when gaming in the sixty to 90 FPS range just like AMD claimed. In loftier framerate situations yous might get a two-4ms comeback which is up to 1 frame, and so at lower frame rates I saw up to a 10ms comeback. The trade-off is in some games you will run across a operation bear on, in others you won't.

This is all fine, it works, it'due south skilful, only nosotros don't think information technology's as important or revolutionary as AMD suggests it is.

Look at the chart below, pulled from their website promoting Radeon Anti-Lag. Information technology shows a range of competitive games receiving twenty to 35% reductions to input latency with Anti-Lag enabled. Why is this different to my testing? Well, that'southward because AMD tested these games running at sixty to 90 FPS rather than the 100s of frames per second you'd commonly expect.

If you lot look at the fine print, AMD says they tested with a Core i7-9700K – a fast gaming CPU – but chose to test at 4K resolution (3840 x 2160). Usually nosotros wouldn't question that, testing games at 4K is fine, some people will be playing at 4K. But they're your more than casual, quality focused gamers who want the best visuals. Competitive gamers who are highly sensitive to input latency, the target for a feature like Radeon Anti-Lag, definitely will non or at least should non be gaming at 4K.

The reason is simple. Gaming at 4K reduces your frame rate considerably compared to playing at a lower resolution like 1080p, and one of the simplest means to reduce input latency is to increase the frame charge per unit. This is why most serious competitive gamers play at 1080p low settings, with high refresh charge per unit displays and fast CPUs. They're frequently CPU limited and playing at 200+ FPS to ensure their gameplay is smooth, responsive, and but minimally afflicted by input lag.

With a proper gaming setup for low latency performance – and we didn't go especially overboard to achieve this for our test – Radeon Anti-Lag is only going to deliver perhaps a ~5ms reduction to input latency. For highly sensitive gamers this might be a big deal, but we certainly could not tell the difference when gaming, although I'grand not the sort of person that is overly sensitive to input lag.

The only conclusion nosotros could come to is Radeon Anti-Lag actually isn't designed for true competitive gamers that want super low input latency, because the gains y'all get in latency-tuned scenarios are minimal.

This leaves it in kind of a weird position. It's not a bad or useless characteristic. If you're casually gaming in that lx to 90 FPS zone for whatever reason, y'all just want a reduction in input latency, great you can at present hit a push button and shave off maybe 10 to 15ms. But if you're more than serious nigh reducing lag, you'll get a much bigger improvement out of but increasing your frame rate. In Battlefield V for example, turning down some settings and going from 70 to 120 FPS shaved off 22ms of input lag, and delivered smoother gameplay. That'south what we'd recommend doing first, simply in the procedure information technology diminishes the advantage you tin get from Anti-Lag.

We were looking forwards to Radeon Anti-Lag condign a significant feature for highly competitive, skilled, latency-sensitive gamers. The ones that enquiry input lag and optimize their setups accordingly. Instead, while it has a modest bear upon for those gamers, Radeon Anti-Lag is more suited to improving the casual gaming feel which conversely we're non sure that group of gamers will care nigh a i-frame input latency reduction, peculiarly if there's the potential for a drop in frame charge per unit.

Some other potential utilize instance could be gamers on a budget who are trying to compete on lower-end hardware -- maybe a Ryzen five 3400G or something like that -- who would already be playing at 1080p low settings on the integrated graphics and sitting effectually that frame rate sweet spot for Radeon Anti-Lag. With nowhere lower to go in terms of getting amend frame rates, information technology could be a handy toggle to reduce input latency further.