W1zzard
09-20-2004, 10:08 PM
[PAGE=Introduction, Packaging]
Introduction
I would like to thank Thermaltake for supplying me with the unit for review.
For the stereotype american the remote control is probably the most important aspect of his home life. That's probably why Thermaltake is the first manufacturer to create a fan controller that can be controlled via infrared remote. This is a great idea if you use your computer to watch movies - turn down the fan to reduce noise while you are watching.
<table class="resulttable" border="1" cellspacing="0" cellpadding="5">
<tr>
<th colspan="2" align="center">Remote Control</th>
</tr>
<tr>
<th align="center">Dimensions:</th>
<td align="center">89.9 x 54.7 x 7.7 mm</td>
</tr>
<tr>
<th align="center">Lift Exception:</th>
<td align="center">45.000 times</td>
</tr>
<tr>
<th align="center">Rated Temperature:</th>
<td align="center">-10°C - +60°C</td>
</tr>
<tr>
<th align="center">Transmit Distance:</th>
<td align="center">12m (open space)</td>
</tr>
<tr>
<th align="center">Battery Voltage</th>
<td align="center">2.8V - 3.2V</td>
</tr>
<tr>
<th colspan="2" align="center">Receiver</th>
</tr>
<tr>
<th align="center">Device Space</th>
<td align="center">5.25" drive device</td>
</tr>
<tr>
<th align="center">Dimensions</th>
<td align="center">148.4 x 42 x 68 mm</td>
</tr>
<tr>
<th align="center">Rated Temperature</th>
<td align="center">0°C - 70°C</td>
</tr>
<tr>
<th align="center">Input Voltage</th>
<td align="center">DC 12V</td>
</tr>
<tr>
<th align="center">Output Voltage</th>
<td align="center">DC 12V</td>
</tr>
<tr>
<th align="center">Output Channels</th>
<td align="center">Four</td>
</tr>
<tr>
<th align="center">Max. Current per channel</th>
<td align="center">1 Ampere</td>
</tr>
<tr>
<th align="center">Rated Frequency</th>
<td align="center">4 Mhz</td>
</tr>
<tr>
<th align="center">Receive Distance</th>
<td align="center">12m (open space)</td>
</tr>
<tr>
<th align="center">Receive Direction</th>
<td align="center">45° (+- 22.5° )</td>
</tr>
</table>
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/overview.jpg
Packaging
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/package1_small.jpg (http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/package1.jpg) http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/package2_small.jpg (http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/package2.jpg)
Box contents:
5.25" Fan Controller
IR Remote Control
Manual
Misc cables
What I find a bit odd here is that no mounting screws are included, on the other hand almost every computer user should have the required screws to mount it.
[PAGE=Remote Control & Front Panel Device]
Remote Control
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/rc_small.jpg (http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/rc.jpg) http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/hook_small.jpg (http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/hook.jpg)
The remote control is only 8 mm high and the size of a credit card, a bit big in my opinion. Its keychain goes together with a hook on the front panel device. I like the idea because this way the remote control has a place to go when not used and won't end up missing.
You could also use the hole in the remote to put it on your keychain - I would feel a bit weird if I ran around with it everywhere.
The IR signals of the remote control are compatible to most universal remotes, so you can learn the two buttons and get away with using your favorite remote instead of having a pile of five.
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/battery_small.jpg (http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/battery.jpg)
The used battery is a very common CR2025 3V battery - replacements are easy to get.
Front Panel Device
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/front_small.jpg (http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/front.jpg)
The color scheme of the brushed aluminium fan controller with black looks good in both aluminium and black cases.
The six LEDs on the left show the current fan speed, next is the IR receiver. Further to the right you see the keychain hook and another LED which indicates that the unit is running. When it receives an IR command the LED turns off for a moment confirming reception.
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/side_small.jpg (http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/side.jpg)
The six mounting holes on each side help a lot when mounting the unit, even in the most funky cases.
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/pcb_small.jpg (http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/pcb.jpg)
On the PCB you can see the four fan output connectors and the plug for the power connector. Also visible in the middle is the microcontroller that decodes the IR signals and controls the fans and LEDs.
[PAGE=Pulse Width Modulation]
What is PWM?
This info is taken with Uller's permission from http://casemods.pointofnoreturn.org/pwm (http://casemods.pointofnoreturn.org/pwm/)
There are two ways we can reduce the fan's speed.
Linear Regulation
<table><tr valign="top"><td>http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/linearreg.gif</td>
<td>The most common way, and the simplest, is to reduce the amount of torque on the fan by reducing the voltage supplied. This is called linear regulation. You can either directly change the voltage supplied (the "7 volt trick", voltage regulators, and step-down transformers - also called DC-DC regulation) or put a resistance in series with the fan, creating a voltage drop (resistors and rheostats).</td></tr></table>
Like everything in electronics, voltage adjustment for fans has pros and cons:
PRO:
Circuitry in the fan to report RPMs or failure still work.
There's no noisy side effects from linear regulation - no buzzing, groaning, etc from the fan.
The torque, although less than normal, is still a steady reliable force, so you won't reduce the life of your fans.
CON:
The excess voltage needs to be dissipated somehow - with the exception of the 7-volt trick and stepdown transformers, all of the solutions above dissipate it as extra heat in the case - and a lot of it - which defeats the purpose of fans. To compound it, it's impossible to properly heatsink a rheostat.
A fan has a minimum torque (about 60% in most cases) needed to spin, so you can't do low speed.
A fan pulls more current at lower voltages.
Pulse-Width-Modulation
<table><tr valign="top"><td>http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/pwmreg.gif</td>
<td>The alternative approach is PWM which keeps the fan spinning with a rapid stream of "taps" - small hard pulses of full torque (i.e. 12V) that keep the fan's inertia up, and no power in between - instead of a low constant torque. Just like linear regulation, this has pros and cons.</td></tr></table>
PRO:
Almost no heat is produced by the circuit - you may even be able to use it without a heatsink.
Maximum torque is applied when it's pulsed on, so you can keep the fan spinning VERY slowly if you do wide pulses that are spread out far apart.
Fans pull a constant predictable current when the pulse stream is "on", regardless of how long the pulse lasts.
CON:
Since there's no constant power for the circuitry in the fan, RPM sensing/failure detection will be erratic at best.
If the pulses are too fast or too slow, the fan may groan or whine at low speeds.
The switching is is hard on the fan's coils, so your fan's lifetime might be very very slightly reduced. It'll change the MTBF, by a few days - but in most cases, the MTBF will actually be increased, since the decreased fan speed effects it much more than the increased winding stress. MTBF means "mean time between failure" and is a reliably statistic which expresses the average time a system will operate without a failure.
<table><tr valign="top"><td>http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/dutycycle.png</td>
<td>The most important factor of a stream of pulses is the duty cycle - it's the ratio of how much time the pulse is "on". For example, 50% duty cycle means the pulse stream spends equal times on and off. 75% duty cycle means 3/4 of the time it's on, and 1/4 of the time it's off. And so on - obviously, 0% means it's off all the time, and 100% means it's full 12V all the time.</td></tr></table>
(Remember - duty cycle is the ratio of on time to total time, and not on time to off time.)
<table><tr valign="top"><td>http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/constfreq.png</td>
<td>With that in mind, there's two things to adjust in a pulsed setup like this - the on time and the off time. It's a pain in the ass to put separate controls for both - plus, it's the ratio that matters, not the individual settings.</td></tr></table>
In practice, what we do is adjust the on time, and regulate the off time to match - so, every pulse STARTS at a regular interval, and we just adjust how long that pulse is. The number of pulse starts per second is called the frequency. Our goal is to keep the frequency constant, and adjust the width of the pulse - this means that as we adjust the on time, the off time needs to decrease, so that they both add up to the same amount of time.
So, what frequency do we use? The lower the frequency used, the slower we can turn the fan, since pulses can be longer and farther spaced - however, fans tends to groan or whine if the pulses come too slow, since it has time to speed up and slow down between pulses. At the same time, we don't want it too fast, or the duty cycle won't be as effective, and it may be so high that you can actually hear it switch on and off as a musical tone.
For simple brushed fans, used in power drills and other machinery, you regularly see frequencies in the range of 5 kHz to 50 kHz (1 Hz = once per second, 2 Hz = twice per second, etc... 1 kHz = 1000 Hz). However, with brushless fans, the electronics inside need time to detect the fan's position and create the correct magnetic field on its coils. So, for brushless fans, we want between 20 Hz and 160 Hz.
Since we're keeping a constant frequency but allowing the length of the pulse to be adjusted, this technique is called pulse width modulation, or PWM for short.
[PAGE=Performance]
Performance
After powered on the fan output will always be set to maximum.
All fan outputs of the XTunner are controlled by Pulse-Width-Modulation. It is not possible to change them individually.
There are 7 speed settings:
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/speed1.jpg
This is the slowest mode. The fan is run at 40% of maximum speed. The first LED is blinking.
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/speed2.jpg
The second speed setting turns the first LED on and runs the fan at 50%
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/speed3.jpg
When the second blue LED is on, the fan is running at 60%
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/speed4.jpg
The first green LED shows you that the output is running at 70%.
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/speed5.jpg
Another LED - another 10%, makes the output go to 80%.
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/speed6.jpg
Almost at full speed - running at 90%, the 5th LED lights.
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/speed7.jpg
On the maximum setting all LEDs are lit and the fan is run at 100%.
According to Thermaltake the unit is rated at 1A per channel, thats 12 Watts - we tested it:
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/1amp_small.jpg (http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/1amp.jpg)
All those fans are connected to one channel - the meter shows 1 Amp. We kept adding fans and at around 1.4 Amps the output power transistor got mighty hot. I would say 1.2 Amps (= 14.4 W) are a good permanent maximum per channel.
Thermaltake claims the range of the remote control is 12m. We verified this and found that with a clear line of sight we could control the fans from a distance of more than 15m.
[PAGE=Value & Conclusion]
Value and Conclusion
<table width="100%" cellpadding="5" cellspacing="0" id="result">
<tr><th>http://www.techpowerup.com/images/dollar.gif</th>
<td>
The Thermaltake XTunner is sold for $20.</td>
</tr><tr>
<th>http://www.techpowerup.com/images/thumbup.gif</th>
<td>
PWM fan control
Excellent realization of a new idea
Signal output is very clean and powerful enough even for big fans
Remote control has a good range
Easy installation
</td>
</tr>
<tr>
<th>http://www.techpowerup.com/images/thumbdown.gif</th>
<td>
Not possible to change individual channel speed
Not possible to regulate speed without remote control
Remote control could be smaller
Not possible to set fan speed to lower than 40%
</td></tr>
<tr><th>8.7</th>
<td>If you have a use for an infrared fan controller, the XTunner will be the perfect thing to get. While there are a few minor shortcomings that could be improved, it's a great product overall.</td></tr>
<tr><th></th><td></td></tr>
</table>
Introduction
I would like to thank Thermaltake for supplying me with the unit for review.
For the stereotype american the remote control is probably the most important aspect of his home life. That's probably why Thermaltake is the first manufacturer to create a fan controller that can be controlled via infrared remote. This is a great idea if you use your computer to watch movies - turn down the fan to reduce noise while you are watching.
<table class="resulttable" border="1" cellspacing="0" cellpadding="5">
<tr>
<th colspan="2" align="center">Remote Control</th>
</tr>
<tr>
<th align="center">Dimensions:</th>
<td align="center">89.9 x 54.7 x 7.7 mm</td>
</tr>
<tr>
<th align="center">Lift Exception:</th>
<td align="center">45.000 times</td>
</tr>
<tr>
<th align="center">Rated Temperature:</th>
<td align="center">-10°C - +60°C</td>
</tr>
<tr>
<th align="center">Transmit Distance:</th>
<td align="center">12m (open space)</td>
</tr>
<tr>
<th align="center">Battery Voltage</th>
<td align="center">2.8V - 3.2V</td>
</tr>
<tr>
<th colspan="2" align="center">Receiver</th>
</tr>
<tr>
<th align="center">Device Space</th>
<td align="center">5.25" drive device</td>
</tr>
<tr>
<th align="center">Dimensions</th>
<td align="center">148.4 x 42 x 68 mm</td>
</tr>
<tr>
<th align="center">Rated Temperature</th>
<td align="center">0°C - 70°C</td>
</tr>
<tr>
<th align="center">Input Voltage</th>
<td align="center">DC 12V</td>
</tr>
<tr>
<th align="center">Output Voltage</th>
<td align="center">DC 12V</td>
</tr>
<tr>
<th align="center">Output Channels</th>
<td align="center">Four</td>
</tr>
<tr>
<th align="center">Max. Current per channel</th>
<td align="center">1 Ampere</td>
</tr>
<tr>
<th align="center">Rated Frequency</th>
<td align="center">4 Mhz</td>
</tr>
<tr>
<th align="center">Receive Distance</th>
<td align="center">12m (open space)</td>
</tr>
<tr>
<th align="center">Receive Direction</th>
<td align="center">45° (+- 22.5° )</td>
</tr>
</table>
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/overview.jpg
Packaging
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/package1_small.jpg (http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/package1.jpg) http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/package2_small.jpg (http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/package2.jpg)
Box contents:
5.25" Fan Controller
IR Remote Control
Manual
Misc cables
What I find a bit odd here is that no mounting screws are included, on the other hand almost every computer user should have the required screws to mount it.
[PAGE=Remote Control & Front Panel Device]
Remote Control
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/rc_small.jpg (http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/rc.jpg) http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/hook_small.jpg (http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/hook.jpg)
The remote control is only 8 mm high and the size of a credit card, a bit big in my opinion. Its keychain goes together with a hook on the front panel device. I like the idea because this way the remote control has a place to go when not used and won't end up missing.
You could also use the hole in the remote to put it on your keychain - I would feel a bit weird if I ran around with it everywhere.
The IR signals of the remote control are compatible to most universal remotes, so you can learn the two buttons and get away with using your favorite remote instead of having a pile of five.
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/battery_small.jpg (http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/battery.jpg)
The used battery is a very common CR2025 3V battery - replacements are easy to get.
Front Panel Device
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/front_small.jpg (http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/front.jpg)
The color scheme of the brushed aluminium fan controller with black looks good in both aluminium and black cases.
The six LEDs on the left show the current fan speed, next is the IR receiver. Further to the right you see the keychain hook and another LED which indicates that the unit is running. When it receives an IR command the LED turns off for a moment confirming reception.
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/side_small.jpg (http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/side.jpg)
The six mounting holes on each side help a lot when mounting the unit, even in the most funky cases.
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/pcb_small.jpg (http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/pcb.jpg)
On the PCB you can see the four fan output connectors and the plug for the power connector. Also visible in the middle is the microcontroller that decodes the IR signals and controls the fans and LEDs.
[PAGE=Pulse Width Modulation]
What is PWM?
This info is taken with Uller's permission from http://casemods.pointofnoreturn.org/pwm (http://casemods.pointofnoreturn.org/pwm/)
There are two ways we can reduce the fan's speed.
Linear Regulation
<table><tr valign="top"><td>http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/linearreg.gif</td>
<td>The most common way, and the simplest, is to reduce the amount of torque on the fan by reducing the voltage supplied. This is called linear regulation. You can either directly change the voltage supplied (the "7 volt trick", voltage regulators, and step-down transformers - also called DC-DC regulation) or put a resistance in series with the fan, creating a voltage drop (resistors and rheostats).</td></tr></table>
Like everything in electronics, voltage adjustment for fans has pros and cons:
PRO:
Circuitry in the fan to report RPMs or failure still work.
There's no noisy side effects from linear regulation - no buzzing, groaning, etc from the fan.
The torque, although less than normal, is still a steady reliable force, so you won't reduce the life of your fans.
CON:
The excess voltage needs to be dissipated somehow - with the exception of the 7-volt trick and stepdown transformers, all of the solutions above dissipate it as extra heat in the case - and a lot of it - which defeats the purpose of fans. To compound it, it's impossible to properly heatsink a rheostat.
A fan has a minimum torque (about 60% in most cases) needed to spin, so you can't do low speed.
A fan pulls more current at lower voltages.
Pulse-Width-Modulation
<table><tr valign="top"><td>http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/pwmreg.gif</td>
<td>The alternative approach is PWM which keeps the fan spinning with a rapid stream of "taps" - small hard pulses of full torque (i.e. 12V) that keep the fan's inertia up, and no power in between - instead of a low constant torque. Just like linear regulation, this has pros and cons.</td></tr></table>
PRO:
Almost no heat is produced by the circuit - you may even be able to use it without a heatsink.
Maximum torque is applied when it's pulsed on, so you can keep the fan spinning VERY slowly if you do wide pulses that are spread out far apart.
Fans pull a constant predictable current when the pulse stream is "on", regardless of how long the pulse lasts.
CON:
Since there's no constant power for the circuitry in the fan, RPM sensing/failure detection will be erratic at best.
If the pulses are too fast or too slow, the fan may groan or whine at low speeds.
The switching is is hard on the fan's coils, so your fan's lifetime might be very very slightly reduced. It'll change the MTBF, by a few days - but in most cases, the MTBF will actually be increased, since the decreased fan speed effects it much more than the increased winding stress. MTBF means "mean time between failure" and is a reliably statistic which expresses the average time a system will operate without a failure.
<table><tr valign="top"><td>http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/dutycycle.png</td>
<td>The most important factor of a stream of pulses is the duty cycle - it's the ratio of how much time the pulse is "on". For example, 50% duty cycle means the pulse stream spends equal times on and off. 75% duty cycle means 3/4 of the time it's on, and 1/4 of the time it's off. And so on - obviously, 0% means it's off all the time, and 100% means it's full 12V all the time.</td></tr></table>
(Remember - duty cycle is the ratio of on time to total time, and not on time to off time.)
<table><tr valign="top"><td>http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/constfreq.png</td>
<td>With that in mind, there's two things to adjust in a pulsed setup like this - the on time and the off time. It's a pain in the ass to put separate controls for both - plus, it's the ratio that matters, not the individual settings.</td></tr></table>
In practice, what we do is adjust the on time, and regulate the off time to match - so, every pulse STARTS at a regular interval, and we just adjust how long that pulse is. The number of pulse starts per second is called the frequency. Our goal is to keep the frequency constant, and adjust the width of the pulse - this means that as we adjust the on time, the off time needs to decrease, so that they both add up to the same amount of time.
So, what frequency do we use? The lower the frequency used, the slower we can turn the fan, since pulses can be longer and farther spaced - however, fans tends to groan or whine if the pulses come too slow, since it has time to speed up and slow down between pulses. At the same time, we don't want it too fast, or the duty cycle won't be as effective, and it may be so high that you can actually hear it switch on and off as a musical tone.
For simple brushed fans, used in power drills and other machinery, you regularly see frequencies in the range of 5 kHz to 50 kHz (1 Hz = once per second, 2 Hz = twice per second, etc... 1 kHz = 1000 Hz). However, with brushless fans, the electronics inside need time to detect the fan's position and create the correct magnetic field on its coils. So, for brushless fans, we want between 20 Hz and 160 Hz.
Since we're keeping a constant frequency but allowing the length of the pulse to be adjusted, this technique is called pulse width modulation, or PWM for short.
[PAGE=Performance]
Performance
After powered on the fan output will always be set to maximum.
All fan outputs of the XTunner are controlled by Pulse-Width-Modulation. It is not possible to change them individually.
There are 7 speed settings:
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/speed1.jpg
This is the slowest mode. The fan is run at 40% of maximum speed. The first LED is blinking.
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/speed2.jpg
The second speed setting turns the first LED on and runs the fan at 50%
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/speed3.jpg
When the second blue LED is on, the fan is running at 60%
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/speed4.jpg
The first green LED shows you that the output is running at 70%.
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/speed5.jpg
Another LED - another 10%, makes the output go to 80%.
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/speed6.jpg
Almost at full speed - running at 90%, the 5th LED lights.
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/speed7.jpg
On the maximum setting all LEDs are lit and the fan is run at 100%.
According to Thermaltake the unit is rated at 1A per channel, thats 12 Watts - we tested it:
http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/1amp_small.jpg (http://www.techpowerup.com/reviews/Thermaltake/XTunner/images/1amp.jpg)
All those fans are connected to one channel - the meter shows 1 Amp. We kept adding fans and at around 1.4 Amps the output power transistor got mighty hot. I would say 1.2 Amps (= 14.4 W) are a good permanent maximum per channel.
Thermaltake claims the range of the remote control is 12m. We verified this and found that with a clear line of sight we could control the fans from a distance of more than 15m.
[PAGE=Value & Conclusion]
Value and Conclusion
<table width="100%" cellpadding="5" cellspacing="0" id="result">
<tr><th>http://www.techpowerup.com/images/dollar.gif</th>
<td>
The Thermaltake XTunner is sold for $20.</td>
</tr><tr>
<th>http://www.techpowerup.com/images/thumbup.gif</th>
<td>
PWM fan control
Excellent realization of a new idea
Signal output is very clean and powerful enough even for big fans
Remote control has a good range
Easy installation
</td>
</tr>
<tr>
<th>http://www.techpowerup.com/images/thumbdown.gif</th>
<td>
Not possible to change individual channel speed
Not possible to regulate speed without remote control
Remote control could be smaller
Not possible to set fan speed to lower than 40%
</td></tr>
<tr><th>8.7</th>
<td>If you have a use for an infrared fan controller, the XTunner will be the perfect thing to get. While there are a few minor shortcomings that could be improved, it's a great product overall.</td></tr>
<tr><th></th><td></td></tr>
</table>