SysLat

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If you play competitive games on the PC, you need to know what system latency is. The following sections will provide a primer on the subject (and possibly another good excuse to scream "LAGGG!!" when you die).

What is SysLat?

SysLat is a new open-source USB measurment device for Windows PCs that aims to help you reduce the latency of your machine, and help you rank up.

Do you ever have those days where you just can't hit shots?

You start questioning your machine, your enemy, or even your own abilities...
Maybe I was just lagging...

I bet my hardware is just getting too old...
Maybe they were cheating?
Maybe I'm sick?
Maybe I didn't didn't sleep well last night?
Or the worst of all... maybe I'm just bad?

Playing with high system latency can feel like you're trying to play while you're sick or tired. Unexplainably, you can't hit shots that you hit all of the time, or that seem so much easier in other games.

It might not be you.

It could be your game settings, background processes eating up your machine's resources, low quality hardware, or more.

With SysLat, you can better identify the source of lag so that you can fix it and get back into the game.

System Latency

What is system latency?

This graphic, taken from Nvidia's page introducing Reflex, is the best illustration of system latency I've found so far.

* Image attribution: Nvidia 2020

Peripheral Latency: The time it takes your input device to process your mechanical input and send those input events to the PC
Game Latency: The time it takes for the CPU to process input or changes to the world and submit a new frame to the GPU to be rendered
Render Latency: The time from when the frame gets in line to be rendered to when the GPU completely renders the frame
PC Latency: The time it takes a frame to travel through the PC. This includes both Game and Render Latency
Display Latency: The time it takes for the display to present a new image after the GPU has finished rendering the frame
System Latency: The time encompassing the whole end-to-end measurement - from the start of peripheral latency to the end of display latency

Comparing PC Performance Metrics

How does system latency compare to other PC performance metrics?

Are system latency and network latency the same?

No, but they can cause very similar issues.

Network latency is the time your game client takes to communicate and return from the game server. It can often be somewhat mitigated(...or exacerbated) by game developer's network code. Examples of these mitigations include Counter-Strike's lag compensation and this video on Overwatch's netcode.

System latency on the other hand, deals solely with measuring your machine. While it can't be said to be more important than network latency, playing with a high system latency can often feel like your "lagging" or experiencing high network latency.

Isn't FPS just as good of a measurement?

While increasing FPS generally correlates with decreasing system latency, the 2 measurements are not the same. FPS measures the throughput of your system, while system latency actually measure the end-to-end time from input to output. Oftentimes PCs can maintain relatively high framerates, but have exceptionally high system latency. While this can make your movements appear or feel sluggish, you often can even tell you're being robbed of precious milliseconds.

Explain it like I'm 5...

Here's an analogy: Do you ever turn on your shower and have to wait for the water to heat up? The water begins flowing immediately, but jumping in is not advisable. You wait a moment for the water to heat up and then you can jump in.
In this case the water is FPS and system latency is the heat of your water. When playing a game, the FPS(water) can be flowing just fine, but your eyes often can't tell whether you're receiving those frames quickly(hot) or slowly(cold).

Importance of System Latency

Why is system latency important?

Average human reaction time is 215 ms according to humanbenchmark.com(there are issues with their testing methodology that I could rant on for hours). Average reaction time for high level gamers is, generally, going to be much lower, meaning that a delay of 15-50 milliseconds can be accounting for 10-35% of your reaction time!

Nvidia's research has shown that a difference of 8 ms (from 20 ms to 12 ms) in system latency can account for 13% faster TTKs(time to kill). That 8 millisecond difference (per frame) compounds to a whopping 182 ms difference in task completion time over a 1.5 second period.

* Image attribution: Nvidia 2020

In the images below, I've drawn hitboxes on an enemy. As this scenario begins, the enemy in the picture begins moving to the left. This occurs on the server (and internally on your machine) before it is actually displayed to you.

The red represents where the enemy's hit box actually is in a moment in time.
The blue box represents what you see on your screen at a certain system latency.
The purple area is the overlap between the 2 areas and represents your best chance to hit the target.

0 ms System Latency	15 ms System Latency	75 ms System Latency

* Disclaimer: The images above are a good estimation of what the system latency issue looks like, but the numbers are not entirely accurate. More accurate & interactive depictions are on the way.

As you can see, at 0 ms system latency, the blue box completely encompasses the red box. "What you see is what you get." As the system latency begins to creep up, the amount of the visible hitbox that is "hittable" decreases.

While the example above is a good depiction of the issues that high system latency can cause, it only paints a part of the story. This is the delay seen on every frame... but your system latency is occurring on every single frame and there is a compound effect that occurs. In a game, you're not firing a single shot, but reacting to the result of each and every shot that you fire. This compound effect is a bit too in-depth for this page, but you can read more about its effects in this Nvidia white paper.

Comparing System Latency Measuring Products

	SysLat	Oscilloscope	High Speed Camera & LED wired to mouse
Availability	Open Source and inexpensive	Expensive	Very expensive
Ease of measurement	Automatically measures and records measuments at regular intervals(~1 measurement every 2 seconds).	Tedious & labor intensive	Tedious & labor intensive
Sensor/Accuracy	High - ~1 khz sensor	High enough - 0.24 khz(for a 240 fps camera)	Extremely high - 85 khz

SysLat is currently the only widely available system latency monitoring solution of its kind. Until now, the best ways to measure system latency were both very expensive and very tedious. In addition to old methods being slow and clunky, Nvidia's two new methods, LDAT and RLA(Reflex Latency Analyzer), are either available to reviewers only or extremely expensive and hardware limited, respectively. Here are some comparisons of what SysLat does compared to other methods.SysLat vs. Old MethodsSysLat vs. LDATSysLat vs. RLA

	SysLat	RLA
Measurements	Constant	Constant
Availability	Open source, inexpensive	Proprietary and obfuscated
Test Position	Anywhere, but preferably corners	Anywhere, without negatively impacting the user
Logging	Strong Logging Capabilities	Limited Logging
Mouse	Acts as a mouse/input device	Accounts for some* mouse latency

Testimonials

Skewjo (Founder): I created this device to help me test different video configurations in Overwatch. In addition to verifying the need to lower my graphics settings, SysLat also helped me identify odd resource issues and handle them before they began affecting too many games. This helped me climb the rankings and made the game much more enjoyable, knowing that my system wasn't actively working against me.

HenMill (Co-Founder): A big Rocket League fan, HenMill had no idea how much playing in "Windowed Fullscreen" mode was affecting his game. Changing the setting to "Dedicated Fullscreen" netted him an average savings of 10 ms system latency. While 10 milliseconds might sound like a miniscule amount, the compound effect that occurs from this delay occurring on every frame. While he couldn't immediately notice his game was more responsive, he was suddenly and "magically" able to land more shots and passes. This occurence is what convinced him to join my cause in making this tool available to everyone.

Purchasing a SysLat Device

Identifying and eliminating your system latency with SysLat is your ticket to higher quality games leading to higher rankings and higher self-esteem. Often times your settings or machine are to blame for holding you back. With SysLat, you can make sure that's not the case.

Purchase a SysLat now.

Articles

Build Your Own
March 18, 2021
A Good Craftsman Never Blames His Tools... But You're Not Very Good Yet.
February 25, 2021
Evolution of SysLat... So Far
November 23, 2020
Milliseconds Matter - Baseball Comparison
November 17, 2020

	SysLat	LDAT

Measurements	Constant	Intermittent and reliant on game animations
Availability	Open source, inexpensive	Reviewers only
Test Position	Test can be positioned anywhere on the screen	Strapped to screen monopolizing valuable space
Logging	Extensive	Very Limited
Mouse	Acts as a mouse/input device	Measures mouse/keyboard input latency
Position Logging	Position of test is logged	Position can not be logged, making the device unable to account for scanout issues
Driver	Software Driven(Could potentially add additional overhead)*	Hardware Driven(Usable from a seperate device)**