In 2007, Lost reached its third-season finale, delivering one of the most classic twists in TV history. Previously, viewers assumed the flashbacks depicted events before the characters were stranded on the island, only to discover at the end that these scenes actually took place in the future. After three full seasons of survival on the island, protagonists Jack and Kate had somehow safely returned to Los Angeles.
Escaping the island had always been the core goal of the series, and viewers originally thought that once they succeeded, Everythinggj would be over. That was until Jack desperately shouted, "We have to go back!"
Now, I find that I have similar feelings about many tech products.
Shortly before that episode of Lost aired, I spent $1,000 on my first high-definition monitor. It was a 26-inch Samsung LCD screen with a resolution of 1366×768. I was still in college at the time, and this monitor served as both the TV in my dorm room and my computer display. Back then, it was definitely considered a high-end product. Compared to the old CRT monitor still in use at home, it was thinner, clearer, and looked much more advanced.
But is that really the case?
Nearly 20 years later, there are still experts well-versed in display technology who are trying every possible way to reclaim what we abandoned back then.
"People over 40 usually remember how clear CRT monitors were during motion, while young people never used CRTs and naturally lack this memory," said Mark Rejhon, founder of the Blur Busters website.
For years, the "Test UFO" browser testing tool on the Blur Busters website has been regarded as one of the standard tools for verifying the motion clarity of modern monitors. The test features a green alien sitting in a red flying saucer, helping users observe how clear the image remains during movement.
Compared to old CRT monitors, LCD monitors from the mid-2000s were simply no match in this regard. At that time, liquid crystal pixels took a long time to switch colors, resulting in noticeable ghosting trails behind fast-moving objects.
The TV I bought with an entire month's salary was already a decent product at the time. But as the HD era had just arrived, the novelty of new technology made me overlook one issue: while I gained higher resolution, I lost the richer colors and smoother motion that CRT monitors originally offered.
And that loss lasted for nearly 20 years.
Today's high-refresh-rate monitors have long moved past the blurry, washed-out images of LCD screens from the 2000s. However, even the most top-tier products still haven't fully caught up with CRTs in terms of motion clarity. This is exactly the problem Rejhon has been working to solve.
Rediscovering the Feel of CRTs
In late 2024, Rejhon collaborated with former NVIDIA developer Timothy Lottes to launch a breakthrough algorithm claimed to simulate the effect of CRT picture tubes. It utilizes high-refresh-rate monitors above 240Hz to significantly reduce motion blur in retro games and other 60 FPS content.
Simply put, this technology attempts to simulate a key characteristic of CRT monitors: the gradual fading of phosphor glow after illumination.
CRT monitors work differently from today's LCD screens. An electron beam scans line by line across the screen, causing phosphors to glow and form the image. After glowing, the phosphors don't extinguish instantly but gradually dim. This effect makes the image appear clearer without causing excessive flickering.
Previously, the common method to reduce motion blur was Black Frame Insertion (BFI), which involves inserting black frames between normal frames. While this reduces ghosting, it causes noticeable flickering, which can be uncomfortable to watch for extended periods.
Rejhon explained that there are mainly two ways to reduce motion blur on monitors: one is to make the image flash quickly like a CRT, and the other is to increase the refresh rate. Both methods shorten the time each frame stays in front of your eyes, similar to using a faster shutter speed on a camera, thereby reducing motion blur.
The advantage of CRTs lies in their ability to let pixels glow briefly for less than a millisecond, thus achieving very clear motion pictures without requiring particularly high frame rates.
Besides software simulation, NVIDIA is also attempting to address this issue at the hardware level.
NVIDIA's G-Sync Pulsar technology has been implemented in some gaming monitors. It combines Variable Refresh Rate (VRR), backlight strobing, and a top-down progressive refresh mechanism to simulate CRT display methods, achieving motion clarity equivalent to 1000Hz.
However, this technology has not yet been applied to OLED monitors and currently only works with NVIDIA graphics cards.
Blur Busters' browser testing tool can simulate the process of a CRT electron beam scanning from the top of the screen downwards
If you still find it hard to understand, you can think of CRT simulation technology as DLSS specifically designed for motion.
DLSS primarily uses technical means to enhance game resolution and visual quality, whereas CRT simulation technology aims to make moving images clearer.
Ideally, a game locked at 60 FPS can achieve motion clarity close to that of 540 FPS after processing with this technology, without needing top-tier graphics cards like the RTX 5090 to brute-force frame rates.
Even a 540Hz monitor may not handle it easily
To test this technology, I used the ROG PG27AQWP-W monitor sent by ASUS.
This monitor has a refresh rate of up to 540Hz, and if the resolution is lowered to 720p, it can even enable a 720Hz mode. The higher the refresh rate, the easier it is for CRT simulation technology to function, further reducing motion blur.
OLED screens have their own advantages. Unlike LCDs that require backlighting, OLED pixels can be turned off directly to display true black, and they offer sufficient brightness, allowing them to better approximate the contrast performance of CRTs. Combined with high refresh rates, it becomes easier to simulate the effect of CRT electron beams scanning lines across the screen.
This technology isn't just for satisfying nostalgic gamers.
Rejhon pointed out that traditional 60Hz Black Frame Insertion and backlight strobing produce noticeable flickering because the system needs to insert black frames between each normal frame.
In contrast, CRT simulation technology uses a top-down progressive scanning method, resulting in a much softer effect. Since part of the screen is always emitting light, it doesn't cause the entire image to repeatedly go black like traditional Black Frame Insertion.
However, even though I had a monitor well-suited for testing, I still found myself overwhelmed by this new technology when I actually started tinkering with it.
I Spent Hours Tinkering to Make the Image Clearer
Blur Busters' technology was first applied in the shaders of RetroArch, a frontend software for emulators. Later, it was also added to the experimental version of a standalone tool called ShaderGlass.
ShaderGlass is a very practical Windows visual effects tool that can overlay hundreds of visual effects onto various content on the desktop, such as scanlines and simulated signal interference, giving the image the feel of an old-fashioned TV.
However, simulating the CRT electron beam is far more complex than ordinary shaders, so developer Mausimus ultimately decided to split it out and develop it into a new tool: ShaderBeam.
Mausimus explained that to achieve the best results with this technology, two things must be done simultaneously: first, maintain precise synchronization with the monitor, as missing even a single frame at such high refresh rates can cause noticeable flickering; second, stay synchronized with the game output, ensuring that every frame rendered by the game correctly corresponds to the simulated CRT scanning process.
Currently, ShaderBeam is the best way to utilize Rejhon's algorithm.
ShaderBeam doesn't look complicated to operate; after launching the program, you just press a shortcut key to overlay the effect onto the game window. But looking simple doesn't mean it's easy to implement. After all, this is a technology that operating systems, graphics drivers, and monitors weren't specifically optimized for, so it's not something big companies like Microsoft, AMD, or NVIDIA can just easily pull off.
Mausimus stated that ShaderBeam can only make the best use of existing features like screen capture and window transparency to get the job done. These features were not originally designed for this purpose, nor do they guarantee precise execution timing. The program is also constrained by the internal scheduling mechanisms of the operating system and graphics drivers, requiring it to strive for sufficient runtime resources to ensure every frame is output on time.
To ensure ShaderBeam runs stably, users may even need to disable many commonly useful features.
For example, disabling Variable Refresh Rate, adjusting graphics driver settings, unplugging the second monitor, using Process Lasso to increase the program's priority, and even modifying the Windows registry.
More interestingly, you can try letting two GPUs share the workload: one runs the game, while the other handles CRT image simulation exclusively. If the processor has integrated graphics, you can try assigning the latter task to the iGPU.
Mausimus stated that assigning the simulation task to another GPU can reduce resource contention with the main graphics card, allowing the program to obtain more stable runtime. The improvement brought by this approach is quite significant.
The problem isn't just insufficient GPU performance; it's that the operating system's allocation of GPU resources is unstable.
If ShaderBeam doesn't receive enough GPU resources in time to output the image, flickering may occur. I encountered this problem: when trying to use the integrated graphics of an Intel processor to output at 1440p resolution and 540Hz refresh rate, the flickering was quite noticeable.
Afterward, I tested different emulators and shooter games, including Quake and Amid Evil, but continued to be plagued by stuttering.
This led me to delve deeper into the sub-frame timing issues of monitors. As my research progressed, the various details of display technology became increasingly complex, and even somewhat bewildering.
Honestly, putting in so much effort to get better visuals in games like Metroid Prime 2: Echoes sounds somewhat crazy.
This game was one of the titles I used for testing. I hoped to recapture the feeling I had back in high school, playing this game on a CRT monitor in a friend's bedroom for the first time, using the GameCube emulator Dolphin.
To troubleshoot issues like stuttering, flickering, and color banding, I spent several hours tinkering, feeling like a mad scientist—and the emphasis is definitely on "mad."
Even getting all the settings right doesn't mean Everythinggj will be fine. The game itself can also affect the results.
For example, some games using Unreal Engine 5 often experience stuttering, which disrupts frame intervals and consequently affects the proper functioning of CRT simulation technology.
When the image truly becomes clear, all the hassle is worth it
However, when I started making Samus drive her Morph Ball in tight circles through narrow areas, I finally saw the true value of this technology.
Even with rapid camera rotation, the pillars in the room remained sharp and clear, without becoming blurred due to motion.
At that moment, I finally understood what Rejhon and Mausimus had been striving for.
Mausimus explained that with this technology, pixel details that would normally be swallowed by motion blur when objects move or the player rotates the view should remain clearly visible.
He cited the pillars in Quake as an example. The surfaces of the pillars have many fine textures. On ordinary monitors, these details often blend together due to motion blur when the camera moves. However, after CRT simulation processing, the textures should remain clearly visible even during movement.
Factorio is also a good test subject. Normally, when players move the camera, the entire scene looks very smooth, but pixel details tend to blur together. With this technology enabled, players should still be able to see details clearly even when the entire scene is moving.
This is precisely the significance of CRT simulation technology: it doesn't simply add scanlines or apply a retro filter to the image, but rather attempts to solve the long-standing motion blur problem of modern displays.
We spent nearly 20 years pursuing higher resolutions, thinner screens, and higher refresh rates, only to discover that some advantages once held by old CRT monitors are still worth rediscovering today.