Overdrive in the monitor, what is it?

No, definitely not! Overdrive technology comes with a couple of significant drawbacks that can render its usage ineffective.

To begin with, Overdrive necessitates the computer to constantly store two images in memory: one that the panel is meant to display at any given moment, and the other that the panel is currently displaying. This requires several megabytes of high-speed video memory! Additionally, there is a need for meticulously tabulated "pseudo-colors" (64×64 for 18-bit and 256×256 for 24-bit matrices) to be utilized for each combination of the current and desired sub-pixel state, along with "resultant colors" that indicate the color that will be achieved by the time of the next matrix image update using those pseudo-colors. This adds another 128 kilobytes of memory and the corresponding logic. Implementing such a system is not a significant challenge for modern video cards (gone are the days when video memory was slow and costly), but it remains unclear as to how the video card will accommodate these 131 thousand numbers unique to this specific matrix. On the other hand, an LCD monitor is well aware of its speed characteristics (they can be measured using specialized equipment) but dynamically correcting the picture based on its previous state poses a new and challenging task that requires a specialized DSP processor.

Another issue is the lack of objective control over the actual state of the LCD panel. This means that an Overdrive system can only approximate the current state of a subpixel based on its state 16.7 ms ago. In traditional systems, small errors and variations in pixel parameters can lead to minor discrepancies in panel color. However, in Overdrive systems, these errors can accumulate and result in significant color reproduction errors and potential distortion in the displayed images. While introducing specific errors in the recalculation tables can help address this issue, it does not entirely solve the problem.

Therefore, what is commonly referred to as the "first generation Overdrive" is actually a rough approximation of the Overdrive system described earlier. Rather than applying a voltage that directly moves the subpixel to the desired state in the given time (corresponding to the screen refresh time), this approach involves applying a voltage that puts the subpixel in an intermediate state, from which it can be quickly switched to the desired color level. For example, to switch from the "0" state to the "200" state, the subpixel can first be switched to "255" and then corrected by switching to the requested "200" state. By rapidly switching between 0 and 255, and quickly switching between states in the range of 190 to 254, we can achieve the desired 200 subpixel transparency units faster than if we had immediately switched from 0 to 200. This approach makes implementing Overdrive easier, as it is stable against errors and does not require precise adjustment of the matrix (rough estimates of its performance are sufficient). However, it introduces another issue – instead of a smooth color transition from dark to light, there is a characteristic brief and quickly extinguished "flash" that can be noticeable to the eye. Unfortunately, we will have to accept this drawback until more advanced and refined methods of controlling panel technology are developed.

MPRT or GtG response speed?

In addition, some monitor manufacturers incorporate a 1ms MPRT (moving picture response time) specification. It is essential to understand that this is different from the GtG response time. MPRT signifies that the monitor utilizes motion blur reduction technology, which reduces the perception of double images by strobing the backlight.

However, an issue arises when the monitor manufacturer claims a 1ms MPRT without displaying the GtG response time. This can mislead potential users into thinking that the monitor possesses a 1ms response time, when in reality, the GtG response time may be around 4-5ms.

While reduced motion blur provides a motion clarity similar to CRT displays, it does have its downsides. It diminishes the maximum active brightness of the monitor and can cause screen flickering. Additionally, it is often incompatible with VRR (variable refresh rate) technologies like FreeSync and G-SYNC on most monitors.

The ASUS VG279QM display with ASUS-exclusive ELMB-Sync technology is capable of utilizing both VRR and MBR simultaneously, making it one of the gaming monitors that can do so.

OverDrive mode and fuel consumption

Some may argue that the disparity in fuel efficiency is negligible and one can opt to not utilize the Overdrive button on the transmission. Certainly, in urban settings, it is left to the discretion of the individual behind the wheel to determine whether or not to engage this button.

However, when driving on the highway, fuel consumption rises when the button is not engaged. So, there is an option to experiment: drive without Overdrive and observe the impact on fuel consumption. Then, press the button and measure the quantity of gasoline or diesel wasted.

As far as my recollection serves me, it’s important to not expect significant fuel efficiency in this scenario. In such cases, it is advisable to consider purchasing a car equipped with a continuously variable transmission (CVT) gearbox. These vehicles are designed for city driving and are more fuel-efficient compared to fuel-hungry automatic transmissions.

Why does the overdrive button not work?

There are several possible reasons for the failure of the overdrive button. Similar to other components in a vehicle, the overdrive button on the automatic transmission has its own lifespan and can malfunction as a result of frequent use and natural deterioration, although this is quite uncommon in practice.

The most frequent reason for the malfunction of the O/D button is damaged wires or poor connection on the connector leading to the button. To resolve this issue, you can dismantle the shift knob and repair the wiring to ensure its proper functioning.

If the button itself, wires, and connectors are in good condition, the problem might be more complex. It is advisable to inspect the overdrive sensor and conduct a diagnosis of the automatic transmission.

Video "Overdrive operation"

The video demonstrates the acceleration of the vehicle by utilizing the overdrive feature.

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For automatic transmission car owners, it may be of interest to understand the principles behind overdrive and its proper usage.

The term "automatic transmission" (A.C.T.) is typically used to refer to hydromechanical planetary gearboxes that can change gear ratios without direct driver intervention. However, in recent years, there have been cars equipped with automated shifting mechanisms in mechanical gearboxes that use electromechanical or electropneumatic actuators. These systems are commonly referred to as "robot" transmissions rather than "automatic" transmissions. It should be noted that a variator, on the other hand, is not considered a gearbox at all. Unlike a traditional gearbox, a variator does not have a fixed set of gears with different ratios. Instead, it smoothly adjusts the gear ratio as needed, making it a type of stepless transmission.

Using the OD mode of the automatic transmission in practice

To comprehend the utilization of the overdrive mode within urban areas, let’s concentrate on a specific illustration. The vehicle can ascend the slope within the flow, consistently modifying velocity from 30 to 70 km/h.

Assuming the overdrive mode is activated, the automatic transmission shall switch to all gears (1,2,3,4). Furthermore, subsequent to accelerating up to 40-50 km, the torque converter shall be locked on the off chance that the driver doesn’t press the accelerator pedal hard.

Allow’s envision that the vehicle has accelerated to 60 km/h, with fourth gear engaged and the engine speed low. On the off chance that at a specific moment you need to quicken, it is not advisable to anticipate a sudden reaction from the accelerator pedal, since the fourth gear is locked, and the revolutions are insufficient for an intensive pickup within this gear.

Just press the gas pedal harder and the kick-down will be activated, causing a sudden downshift and acceleration. This situation repeats many times. Naturally, this significantly reduces comfort and also wears out the gearbox faster due to constant gear shifting.

If you switch off the overdrive, the car will only move on 3rd gear when under load. It will respond more quickly to the gas pedal, with higher engine revs. There is enough traction for acceleration without the need to shift "down".

However, it should not be assumed that disabling the 4th gear will increase fuel consumption. The fact is that constantly using the kick-down mode when the overdrive is engaged eventually leads to higher fuel consumption in urban conditions.

It appears that understanding how to operate the overdrive mode and knowing when to engage or disengage it is crucial. As mentioned earlier, it is advisable to deactivate the overdrive in the following scenarios:

• During active driving at low velocities;
• During extended descents or climbs;
• When the driving pace frequently varies;
• For smooth driving at speeds up to 50 km/h;
• When towing a trailer or transporting cargo;
• When passing at moderate speeds;

Furthermore, it is noteworthy that disabling the overdrive will result in a rapid increase in engine speed, potentially reaching the "cut-off" point.

Furthermore, activating or deactivating the O/D mode via a dedicated button is crucial, as diverting attention from the road while traveling at high speeds, particularly while overtaking, can pose a significant safety risk. Therefore, the most optimal approach for overtaking on the highway is to rely on kick-down instead of relying on overdrive.

The only time there is an exception is when you are safely passing slower vehicles. In this scenario, the overdrive feature is turned off ahead of time and then the passing can begin; if needed, the kickdown feature can also be activated simultaneously with the overdrive turned off.

To sum up, regardless of the type of transmission and the available modes of operation, it is crucial to accurately anticipate the situation, taking into account the road conditions and the specificities of the automatic transmission’s operation on the particular make and model of the car. Only after ensuring complete safety, can passing, lane changes, and other maneuvers be executed.

Overdrive in practice

Usually, manufacturers don’t disclose the details about the panels used in their products. However, you can determine if a monitor supports Overdrive by checking its specified response time. If the manufacturer simply states the response time without any additional information or mentions that it is measured according to the ISO methodology, then it is likely an "old-school" monitor that does not utilize any tricks. On the other hand, if the specifications mention "grey-to-grey" switching time (GTG), then the monitor most likely supports Overdrive. The GTG specification was introduced to provide a more objective assessment of LCD monitor performance by measuring pixel switching time not only between the fastest "black-to-white" (BTW) transitions, but also between the slowest "grey-to-grey" transitions. For example, the ISO switching times for the mentioned panels at the beginning of this article are 18 and 8 ms for BTW, while the GTG switching times are 43 and 24 ms, respectively. From a marketing perspective, it is not advantageous to specify GTG for "traditional" monitors as it is better to only mention the standard ISO values. However, for "overclocked" monitors with Overdrive technology (which usually do not have very low BTW times), it is more reasonable to provide latency values and indicate that they are measured using a "more accurate" system. Nevertheless, it is important not to solely choose a device based on its ultra-low GTG values as these figures may not always reflect real-world performance.

The high price is the only drawback of new LCD monitors with MVA-matrices. Over time, the price will reduce, but if you are eager to experience the technology now and don’t want to spend an additional $100-150 on a good 17-inch monitor, you can try implementing "homebrew" Overdrive using a graphics card. For ATI GPU-based products, you will require an accelerator from the X300/X600/X700/X800 family and any driver that supports these GPUs. For nVidia GPU-based products, a GeForce from the six thousandth series (or older) and ForceWare 70.xx (or older) drivers are needed.

Menu

All the buttons on this model have touch-sensitive functionality – including the embossed power button that is recessed into the case. The menu control buttons have a more traditional appearance and they blend seamlessly into the panel, except for the subtle symbols.

These buttons can be utilized without accessing the menu to switch between video inputs, change i-Style Color video modes, and adjust the volume.

Within the menu, the initial option is "Image Adjustment" where you can make modifications to brightness, contrast, enable eco-mode, overdrive, and dynamic contrast. Next is the selection of video input (with the alternative to switch to "auto" mode) and then volume control (with the selection of audio input).

In the following option, "Color Setting", you have the ability to modify the color temperature (choose from presets such as "Warm", "Normal", or "Cold"), activate i-Style Color mode, or manually adjust the colors. The "Information" category presents details about the current video mode, "Manual Image Adjustment" provides options for analog connections, and in the final category, "Setup Menu", adjustments can be made to the OSD menu behavior, language selection, deactivation of the activity indicator glow, and reset of all settings to their default values.

How to "overclock" the matrix

So, the task can be summarized as creating a matrix with an average response time of around 10-20 ms. Interestingly, there is no need to enhance TN+Film technology to achieve the desired 4-6 ms response time based on the ISO standard using the traditional approach. By enhancing the control scheme of the LCD panel, it is possible to achieve this for the existing, albeit slower, matrices. All that is required is to shift the operational point for switching all pixels to the "fast" range. If the rotation of liquid crystals is not instantaneous, there is no reason why we cannot initiate it quickly and then pause halfway.

To return to the graphs, let’s first examine how the transition from fully opaque to semi-transparent variations occurs in the case of our "average matrix" (Fig. 4). Now, let’s suppose we have an LCD panel that refreshes its image 60 times per second (with a frame refresh time of 16.7 ms) and attempt to slightly ‘overclock’ it by reducing the matrix response time to match the image refresh period. We will introduce a hypothetical intermediate color that can be achieved through fast matrix switching. However, instead of allowing the matrix to fully transition to this color, we will halt the process at the desired intermediate value by adjusting the voltage on the subpixel during the next screen refresh (indicated by a bold vertical line). If executed correctly, the result will be as shown in Figure 5.

Impressive, isn’t it? When we plot the response time of the "enhanced" matrix on our graph (in an orange color), we observe the following illustration (Fig. 6).

So much for the "sluggish" matrix! It appears that the "idiotic" direct control circuit, which simply recalculates the desired brightness level of a subpixel into the corresponding voltage, does not enable the panel to display its full potential. However, if we slightly upgrade the circuit (to take into account not only the desired brightness level, but also the current level), it becomes quite effortless to achieve frame scans of 60 and even 100 Hz on the current matrices. This implies a complete resolution to the issue of inadequate response time of LCD matrices.

However, I haven’t mentioned all the enticing features of Overdrive.

The point is, there’s no need to upgrade the actual panel electronics to utilize this technology! All that’s required is that the video card supports Overdrive! Whether the panel electronics take into consideration the previous pixel color value and adjust the signal level accordingly for one screen refresh cycle, or if the graphics processor of the video card does so, providing the LCD with a corrected image compensating for matrix lag, it doesn’t matter. Additionally, using Overdrive through the video card is the most widely supported option, as nearly all video card manufacturers offer some form of support for it.

ATI refers to this function as LRDC and it is a component of their LCD Enhancement Engine (LCD-EE) technology. On the other hand, nVidia calls it LCD overdrive and includes it in their PureVideo technology. To enable this feature, you simply need to activate the corresponding technology in the driver settings. Below, we will provide information on the compatible driver versions for this purpose and reveal the location of the hidden settings. However, before we delve into these details, let’s reflect on the following query.

Why the "Overdrive" button does not work

There may be a malfunction with the "Overdrive" button on the automatic transmission. For instance, when the Overdrive mode is engaged, the dashboard display may fail to indicate that the Overdrive is on. Conversely, if the button is turned off, the corresponding light will illuminate.

If the "OD off" signal does not go out when you press the button, it indicates that the key is faulty. The possible causes of this failure are:

• physical wear and tear on the key;
• key reaching the end of its life;
• poor contact;
• broken wires;
• defective gearbox.

In the case of a faulty gearbox, it is necessary to promptly contact a service center to schedule a diagnostic check. This is not something that can be easily resolved on your own. Specialized equipment, such as a scanner and specific software, are required for the task. Therefore, if you are unable to activate the key, it is best to seek the assistance of experienced mechanics at a service station.

Overload and variable refresh rate

When utilizing FreeSync/G-SYNC, which syncs the refresh rate of the monitor with the frame rate of the graphics processor in order to eliminate screen tearing and stuttering, there are certain additional considerations to take into account concerning overload.

Gaming monitors that come with built-in G-SYNC possess variable overload, allowing them to adjust the overload setting to match the refresh rate, resulting in optimal performance at any frame rate/refresh rate.

Meanwhile, FreeSync monitors lack this feature. So, for instance, if you are running at 144 FPS with a high overload, and your frame rate drops to approximately 60 FPS, the overload will be too powerful for 60 Hz/frames per second and will consequently lead to overshoot. Fortunately, this occurrence is quite rare.

Certain FreeSync models, like the Nixeus EDG27, include an Adaptive Overdrive feature that dynamically adjusts the overdrive setting based on the refresh rate. Although it may not be as effective as G-SYNC’s variable overdrive, it helps prevent image doubling and overshoot in specific situations.

Conversely, some FreeSync monitors are unable to simultaneously support FreeSync and the highest overdrive option.

In such cases, we recommend disabling FreeSync and utilizing High Overdrive at a higher frame rate. Alternatively, you can opt for Medium Overdrive and FreeSync at a lower frame rate. The choice between the two will also depend on your personal preference and whether you are more sensitive to screen tearing or image doubling.

Which response time acceleration option should I use?

In order to adjust the overdrive settings of the monitor, you need to navigate to the on-screen display (OSD) menu and locate the overdrive option. This option is usually found under one of the following names: TraceFree (on certain ASUS monitors), Rampage Response, Overdrive, OD, or Response Time.

Within the menu, you will have the ability to choose from several different options. The specific names of these overdrive levels will vary depending on the particular model, and there may be a varying number of levels available between different monitors.

The level settings for monitor overdrive are typically categorized as Slow, Normal, Fast, Fast-Low, Medium, High, Highest, or numeric values. With the ASUS TraceFree feature, you can adjust the overdrive in increments of 10 from 0 to 100. Some monitors also offer the option to completely disable overdrive.

If you have a modern LED backlit monitor with a refresh rate of 60Hz or 75Hz, it is unlikely that the response time will be faster than the display refresh cycle.

In most cases, you won’t notice noticeable halos or trails of rapidly moving objects even when the overdrive is set to "Off" or "Low". However, the Medium or Normal setting usually provides the best results. Using too much overdrive can lead to reverse ghosting or pixel ejection, so it’s recommended to only use it if you are experiencing excessive motion blur in fast-paced games.

For optimal gameplay, displays with higher refresh rates require overdrive. To determine the best acceleration setting for your monitor’s refresh rate, we recommend using the UFO halo test from BlurBusters.

It is crucial that your gaming monitor has effective overdrive. Some monitors have poorly optimized overdrive, like the Samsung CHG70, which only offers one overdrive preset that is too intense at lower frame rates and leads to noticeable overdrive. Therefore, when searching for a gaming monitor, it is not sufficient to simply consider response times.

In our monitor reviews, we always assess the display’s overdrive implementation if it warrants attention.

Therefore, when searching for a gaming monitor, it may not suffice to solely examine the response time. In our evaluations of monitors, we always assess the overdrive implementation of the display if it warrants consideration.

Principle of operation

The audio effect alters the signal by engaging in "gentle" amplitude limiting (as seen in the image below).

This means that instead of abruptly cutting off the peak of the signal (which in this case is a sine wave), it is softly clipped. This soft clipping causes the output signal to start distorting in relation to the input signal’s level. What is the purpose of this?

By utilizing overdrive for processing guitar signals, one can accentuate the sound dynamics. Moreover, the distortion of the guitar signal varies based on the strength of the strings. That is why guitarists frequently utilize this effect, considering its versatility and adjustability, unlike fuzz and distortion.

Application

• During live performances, the primary use of distortion is to process guitar signals.
• When it comes to studio recording, one can intentionally distort a variety of timbres, including single-voice sounds, instrumental sounds, and vocals. This can be done to add aggression, despair, guile, and other emotional elements, as well as to incorporate subtle wheezes and sighs commonly found in commercial music.
• By engaging in preliminary preparation of the musical material, such as eliminating certain sounds, enhancing the attack, specifying the ending, and compressing the dynamic range, the possibilities of distortion can be further expanded.

Performers

Stevie Ray Vaughan is renowned for being a prominent musician who has incorporated the sound effect into his performances. His distinct sound can be attributed to his utilization of the iconic Ibanez Tube Screamer overdrive pedal.

Another noteworthy mention would be Edward van Halen, who is widely recognized for his signature tube overdrive sound achieved with the Boss SD-1 pedal.

Devices

Now you have the option to manipulate the sound to a desirable level without compromising on volume, by incorporating pedals that exclusively offer classic "crunchy" tones, organic and soft, as opposed to simply amplifying the volume and overdrive like before.

In addition to the previously mentioned Ibanez Tube Screamer and Boss SD-1 devices, there are also other noteworthy options:

Another intriguing approach to achieve natural distortion is by utilizing boosters. The unique feature of boosters is that they do not alter the original sound of the guitar, rather they preserve the authentic characteristics of the amplifier and the guitar, while simply boosting the volume.

Today, there are advanced digital signal distorters that allow for successful sound processing.