OSRTT vs OSLTT – Which one is for you?
One question I get asked more than anything is, between my two hardware devices, OSRTT and OSLTT, which one should you buy? I thought that was worth explaining, so here goes! If you’d rather not find out the features of each and want the cliff notes version, OSRTT is a monitor testing tool. It does response times and monitor latency. If you want to test latency in games, on consoles, or with peripherals, you want OSLTT instead. OSRTT is a response time tool for monitors, OSLTT is a latency tool that works with lots of stuff.
So that’s the basics, but if you’re willing to hang on here, I’d like to dive a bit deeper into what each of these things can do to help you understand which tool is right for you! I’ll start with OSRTT, or the Open Source Response Time Tool. As the name suggests, this is an open source tool for testing monitor response times. This one specifically is OSRTT Pro, essentially the version two of my original tool, which swaps out the sensor package for one I designed myself, including a custom digital potentiometer that allows the tool to comfortably range from 80 to over 1000 nits and still get a good measurement. The primary use for this is testing monitors, and specifically testing their response times. It comes with full heatmaps and an interactive raw data viewer to catch things like manufacturers faking adaptive sync support – something I’ve done twice now!
The OSRTT software also gives you full control of how you run your tests – you can use the default methodology that I use and prefer, or you can pick from a number of other standards from the likes of Hardware Unboxed’s 3% of the RGB values tolerance, TFT Central’s fixed RGB 10 offset, or the outdated, outmoded VESA standard of 10% of the light level tolerance. You can also show overshoot as a function of light level or RGB values, and as a percentage or not. Because it saves the raw data, everything is transparent. You can verify the results if something looks fishy, and if you’re extra keen, you can even vet or modify the code itself.
The other feature, latency testing, is incredibly useful too. It is specifically only for monitors, but gives you the on-display latency, as in how long it takes from the newest frame leaving your graphics card to having the monitor start to display it. Anything where the average is around half the refresh rate is perfect, whereas if some results start to take longer than one frame, that’s less good. It’s a helpful tool when testing displays.
As for the latency tool itself, that one is rather different. It retains the monitor latency testing mode as you might expect, but the addition of a microphone jack and a two pin input make this a lot more versatile for testing all sorts of devices for their latency. Let me run you through some of the options. One of the most popular modes is testing keyboards and mice for their click or keypress latency. You can do that either with the microphone, where it listens for you hitting the key or switch, or using the two pin input soldered directly to the switch. Both work well, although for high polling rate peripherals – like 8,000 hertz – if you want the utmost accuracy you’ll want to use the 2 pin option.
I think the next most popular mode is the ability to test a games’ latency. This uses the light sensor and can either click the left mouse button to trigger an action, or if the game you want to test doesn’t have any good sources of light from a mouse click, you can just have the mouse move! You’ll want to line up on a sharp edge – either a dark edge with a light area to the side, or vice versa. You just need the light level change. Then hit go and it’ll automatically run as many times as you like to get as accurate a result as it can. Pretty handy! In a recent update I also added the ability to pre-test your system’s latency so you can then isolate the game’s latency from your systems’.
You can also test audio devices – this is one I’m still working on improving so you’ll have to bear with me on this, but it certainly can and you’ll get comparable, if imperfect results right now. One mode I’ve just added is the ability to use the microphone as the trigger, and the light sensor as the data source. That is, essentially, a console testing mode. You just put the microphone close to the button you’re going to hit, then, with the sensor on your screen, hit the button and wait for the action to happen. Repeat as many times as you like, then hit the button on the tool to end the test. Nice and simple! You’ve also got the option to hook the 2 pin input to anything you like that can output ideally no more than 5V DC, although it is rated for up to 50V DC, and use that to trigger the light sensor. In future that will also include the microphone as the sensor too.
OSLTT, as you might expect, has its own software. It has a much more modern look, and a bit of a different way of interacting with it. All of the settings are right here for you to pick from, which I think makes the experience of using this pretty simple and easy. It still has a results viewer where your data will show up once you’ve ended the test, or where you can import existing results to view them again. Much like the response time tool, all the raw data gets saved on top of the processed data so you can see exactly what’s going on and vet the results yourself. Transparency is still the name of the game here!
While there is plenty more I could talk about with these tools, I think that’s a good overview of what each of them do, and hopefully that’s enough information for you to be able to decide which is right for you! As someone who reviews both monitors and peripherals, I’m incredibly happy to have both at my disposal. If you’d like to get your hands on one – or both – of these tools, head to OSRTT.com and check them out. I build each unit by hand right here at home, built to order, and ship them to anywhere worldwide.
