Question My new PC fans run at 100% all the time ?

Sep 14, 2023
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Hello TomsHardware people!

I just finished building my very first gaming PC yesterday and what joy it was powering it on for the first time and setting it up. Such a fulfilling experience.

I built my pc in the NZXT H9 flow tower which comes with 4 fans and then i bought 6 extra Arctic F12 fans. Since my mobo only had 6 sys_fan slots, i bought Arctic PWM Case Fan hub - 10 ports so i could connect all my fans to that. Now the problem is that all my fans run at 100% speed all the time. I cant change this in any fan control software or even in the bios. From what i can see the problem is that all the fans is 3 pin and the fan hub is 4 pin. And it has something to do with PWC and DC. Im sorry for being so clueless but i have absolutely no knowledge on the area and could really use some help to find a solution since it makes a lot of noise when they run at 100% all the time and i also dont think it is healthy for the fans to run at 100% all the time.

Do i need to buy another fan hub? Should i buy splitter cables to connect multiple fans to different sys_fan slots? Would i need to buy 10 other fans to get it to work?

All solutions and suggestions are welcome.

FANS: https://www.proshop.dk/Kabinet-Koeler/Arctic-F12-case-fan-Kabinet-koeler-120-mm-Sort/2986953
FAN HUB: https://www.proshop.dk/Kabinet-Tilbehoer/Arctic-PWM-Case-Fan-hub-10-ports/2960053

Best regards
VenGeee
 
4 pin fans are pwm control speed via a pulse from motherbaord/hub
3pin fans are dc. and only way to control speed is via voltage


I don't think changing hub would help as its the fans, not the hub.

could be they have different models -

DC - https://www.arctic.de/en/F12/ACFAN00201A
PWM - https://www.arctic.de/en/F12-PWM-PST/ACFAN00200A

I don't know if a splitter would help.

If you want to vary the speed of DC fans, the only option is to vary the input DC supply. The DC power supply can be reduced below 12 V for lower speeds. There are still limitations in the percentage decrease in the speed of DC fans. All the DC fans are specified with a minimum threshold voltage rating; if the voltage falls below the threshold, the fan starts to stall. For continuous spinning motion, this minimum voltage needs to be supplied.

DC voltage control is the method to vary DC fan speed and this can be implemented by incorporating resistances in the supply wire. The voltage drop across the series resistor reduces the voltage reaching the fan supply pin, automatically slowing the speed of the fan. If the resistor connected is a variable one, the fan speed can be varied until it stalls at a minimum threshold voltage. Nowadays, standalone fan controllers with knobs are available for this type of DC fan speed control.

I see if anyone has any suggestions
 
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4 pin pwm hub is no different to the motherboard, it's just expanding headers which still needs the fans (4pin versions) to communicate. For the hub to act like a separate speed controller via software would be interesting so it didn't matter if 3 or 4 pin fans were connected but don't think such a thing exists.
 
4 pin fans are pwm control speed via a pulse from motherbaord/hub
3pin fans are dc. and only way to control speed is via voltage


I don't think changing hub would help as its the fans, not the hub.

could be they have different models -

DC - https://www.arctic.de/en/F12/ACFAN00201A
PWM - https://www.arctic.de/en/F12-PWM-PST/ACFAN00200A

I don't know if a splitter would help.



I see if anyone has any suggestions
Thanks for this ellaborate answer! I think i understand it more clearly now.

So if i bought 10 of the PWM fans i would be able to control the fan speed from my bios/fan speed software?

The one think i dont understand though is how i would go about lowering my voltage to lower the fan speed of my current fans?
 
So if i bought 10 of the PWM fans i would be able to control the fan speed from my bios/fan speed software?
most likely, yes. Its an shame you find out afterwards. I had to replace my case fans as they were DC but that was only 3 fans.

There are restrictions, it depends how many fan headers on Motherboard as running all of them off hub will have them all running same speeds. Having them all at same speeds, can cause strange noises if the wind pattern is bad.

Better to have them at different speeds by using more than one header. I also use https://github.com/Rem0o/FanControl.Releases to control most of my case fans and keep them at different speeds.

The one think i dont understand though is how i would go about lowering my voltage to lower the fan speed of my current fans?
I wasn't sure myself, i think there might have been physical controllers you put in front of case that controls fan speeds. I might be wrong. I know I had a CPU with a speed controller on its fan a long time ago.
 
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most likely, yes. Its an shame you find out afterwards. I had to replace my case fans as they were DC but that was only 3 fans.

There are restrictions, it depends how many fan headers on Motherboard as running all of them off hub will have them all running same speeds. Having them all at same speeds, can cause strange noises if the wind pattern is bad.

Better to have them at different speeds by using more than one header. I also use https://github.com/Rem0o/FanControl.Releases to control most of my case fans and keep them at different speeds.


I wasn't sure myself, i think there might have been physical controllers you put in front of case that controls fan speeds. I might be wrong. I know I had a CPU with a speed controller on its fan a long time ago.
I just made a discory when i checked my invoice and it was in fact the PWM fans i bought.


It also says PWM on the box. But it was only a 3 pin connector on them - is there something im missing here?

I can try to post a picture of it when i open my PC a bit later today.
 
ss1KowY.jpg


The "PST" in the product name identifies our popular PWM sharing technology, where the PWM signal from one fan is shared with other fans.

looks like you can daisy chain them.
https://www.arctic.de/en/blog/what-exactly-is-pwm-pst << look at this

weird its the English URL but forums sees it as German

it looks to me like power cable should have two attachments, one for 4 pins, and the other is to connect fans together.


read your manual? https://support.arctic.de/en/p12-pwm-pst
 
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It really doesn't matter whether you have PWM or DC controlled fans UNLESS you're motherboard or fan hub does not support both modes, and you have to manually select which mode you want to use for each fan OR for the header that you're using to control your hub if it requires one.

Your hub only supports full speed operation for DC controlled fans so as Colif has mentioned you either need a different hub that has speed control support for DC fans, or simply use the fan headers on your motherboard with splitters which you can attach up to three fans per header with so long as they aren't some out of the ordinary fan that pulls more current than typical case fans do, or get all PWM fans if you wish to use the controller you already have. Either way, if your fan or fan hub connects to the motherboard you need to make sure that header is assigned to operate using the correct "mode", PWM or DC, in the BIOS, otherwise your results might not be as expected.

So if you have four fan headers not counting the CPU_FAN header, you could technically run up to 12 fans off just the board headers and not even need a hub. If the fans can be daisy chained, then really you don't even need any splitter cables. Just connect them to the fan headers on the motherboard and daisy chain up to three of them per fan header.
 
4 pin pwm hub is no different to the motherboard, it's just expanding headers which still needs the fans (4pin versions) to communicate. For the hub to act like a separate speed controller via software would be interesting so it didn't matter if 3 or 4 pin fans were connected but don't think such a thing exists.
It absolutely exists. This is exactly what the NZXT Grid+ v2 and v3 does. Fans are COMPLETELY controlled via software and both PWM and DC modes are supported. You don't even connect it to a fan header. The problem with them though, while they do work mostly as intended is that you MUST use the NZXT CAM software with them and that software has historically not only been buggy as hell but it was extremely notorious for it's hidden phone home routines. Seems like NZXT isn't selling these anymore but they are still available through most online PC hardware retailers or on Ebay. Mostly useful for older systems that had motherboards which did not fully support one type of mode or another properly or at all, especially prior to when boards started including support for both control modes per header.
 
Okay guys, i just made a discovery which turns my entire problem upside down. When i checked my invoice and the box the fans came in it was actually PWM fans.


This is the fans that i have. I just opened my computer and checked, they are 4 pin connecters.

But the 4 fans that was in my NZXT tower from the start are not 4 pin connectors, they are 3 pin connectors. So now im thinking the problem is that my fan hub has 6 PWM fans connected and 4 DC fans connected, so that might be why i cant change the speed, because it has 2 different types connected?

NZXT FANS 3 PIN CONNECTOR: View: https://imgur.com/a/M00GBOT


ARTIC FANS 4 PIN CONNECTOR: View: https://imgur.com/a/nDhxFgX


THE CABLE FROM MY FAN HUB TO MOBO(2 PICS HERE): View: https://imgur.com/a/cmYaQUs


So is my solution just to buy 4 more PWM fans and i should work or what do you guys think?
 
@Colif put a word out and now i'm here. :)

As far as fan hubs go, here are few examples of fan hubs:
Silverstone fan hub. Can control 4-pin fans without issues via PWM mode but 3-pin fans plugged to it will run 100% all the time. Supports up to 8x fans,
specs: https://www.silverstonetek.com/product.php?area=en&pid=526
amazon: https://www.amazon.com/SilverStone-System-Cables-Black-CPF04/dp/B00VNW556I

Thermaltake Commander FX. Can control only 3-pin fans via DC mode and it doesn't support 4-pin fans. Supports up to 10x fans,
specs: removed from Tt site for some reason, probably EOL.
amazon: https://www.amazon.com/Thermaltake-Commander-SATA-Powered-AC-007-AN1NAN-A1/dp/B00O5VX6UQ

Phanteks fan hub. Is unique since it can control both, 3-pin and 4-pin fans via PWM mode. Supports up to 6x fans.
specs: http://www.phanteks.com/PH-PWHUB.html
amazon: https://www.amazon.com/Phanteks-PWM-Fan-Controller-PH-PWHUB_01/dp/B00M0R05WE

Revised variant of the unique Phanteks fan hub, support of 4x 4-pin fans and 3x 3-pin fans,
specs: https://phanteks.com/PH-PWHUB_02.html
amazon: https://www.amazon.com/Phanteks-Universal-Fan-Controller-PH-PWHUB_02/dp/B07NHQRCRM

All fan hubs are small enough to be mounted either behind MoBo tray or in the HDD drive slot. Though, do note that regardless the fan hub used, all fans connected to it will run in sync (same speed). If you want individual control over each fan, then you'll need a fan controller.

For your use, two the revised variants of Phanteks fan hubs should do, since you can connect;
Hub #1 - 4x 4-pin and 3x 3-pin
Hub #2 - 2x 4-pin and 1x 3-pin
OR
Just buy one Phanteks unique hub and connect the rest of the fans to MoBo.
OR
Buy Silverstone fan hub for 4-pin fans and connect 3-pin fans to MoBo. Plenty of options what to do.
 
@Colif put a word out and now i'm here. :)

As far as fan hubs go, here are few examples of fan hubs:
Silverstone fan hub. Can control 4-pin fans without issues via PWM mode but 3-pin fans plugged to it will run 100% all the time. Supports up to 8x fans,
specs: https://www.silverstonetek.com/product.php?area=en&pid=526
amazon: https://www.amazon.com/SilverStone-System-Cables-Black-CPF04/dp/B00VNW556I

Thermaltake Commander FX. Can control only 3-pin fans via DC mode and it doesn't support 4-pin fans. Supports up to 10x fans,
specs: removed from Tt site for some reason, probably EOL.
amazon: https://www.amazon.com/Thermaltake-Commander-SATA-Powered-AC-007-AN1NAN-A1/dp/B00O5VX6UQ

Phanteks fan hub. Is unique since it can control both, 3-pin and 4-pin fans via PWM mode. Supports up to 6x fans.
specs: http://www.phanteks.com/PH-PWHUB.html
amazon: https://www.amazon.com/Phanteks-PWM-Fan-Controller-PH-PWHUB_01/dp/B00M0R05WE

Revised variant of the unique Phanteks fan hub, support of 4x 4-pin fans and 3x 3-pin fans,
specs: https://phanteks.com/PH-PWHUB_02.html
amazon: https://www.amazon.com/Phanteks-Universal-Fan-Controller-PH-PWHUB_02/dp/B07NHQRCRM

All fan hubs are small enough to be mounted either behind MoBo tray or in the HDD drive slot. Though, do note that regardless the fan hub used, all fans connected to it will run in sync (same speed). If you want individual control over each fan, then you'll need a fan controller.

For your use, two the revised variants of Phanteks fan hubs should do, since you can connect;
Hub #1 - 4x 4-pin and 3x 3-pin
Hub #2 - 2x 4-pin and 1x 3-pin
OR
Just buy one Phanteks unique hub and connect the rest of the fans to MoBo.
OR
Buy Silverstone fan hub for 4-pin fans and connect 3-pin fans to MoBo. Plenty of options what to do.
Thanks for the elaborate answer! Really was helpful. So sounds like the best i could do is to buy a phantek hub and connect the 3 Pin and some of the 4 pin to it and the rest of the 4 pin to to the mobo itself. That would let me control all of the fans right?

Also, do you know if the reason i cant control the the 4 pin fans now is because my current fan hub also has 3 Pin fans connected? Or is it just because my fan hub cant control any fans?
 
Also, do you know if the reason i cant control the the 4 pin fans now is because my current fan hub also has 3 Pin fans connected? Or is it just because my fan hub cant control any fans?
Your Arctic fan hub works like so;
* full +12V power from sata power cable
* PWM signal from MoBo, IF the MoBo fan header is set to PWM mode
* RPM feedback to MoBo (only 1st fan speed is shown)

If you do not have the wire between fan hub to MoBo and/or fan header on MoBo is set to DC mode, all connected fans will run 100% since they get the full power directly from PSU, without any voltage control.

To control 4-pin PWM fans;
* fan needs full +12V at all times
* fan needs PWM signal, which then adjust the fan speed

To control 3-pin DC fans;
* fan needs ~5V-12V
* fan speed is directly linked to how much power it receives
Note: 4-pin fans can be controlled by voltage regulation as well (DC mode)

Since your Arctic fan hub doesn't offer any voltage control method, all 3-pin fans hooked to it will run 100% at all times. And if you have issues with PWM signal (e.g no PWM signal), 4-pin fans will also run at 100%.

So sounds like the best i could do is to buy a phantek hub and connect the 3 Pin and some of the 4 pin to it and the rest of the 4 pin to to the mobo itself. That would let me control all of the fans right?
Yes, this is one option. Getting the revised Phanteks hub (the one that supports up to 7x fans) also gives you Manual control method (via wired remote), if you don't want to rely solely on MoBo control.
 
Your Arctic fan hub works like so;
* full +12V power from sata power cable
* PWM signal from MoBo, IF the MoBo fan header is set to PWM mode
* RPM feedback to MoBo (only 1st fan speed is shown)

If you do not have the wire between fan hub to MoBo and/or fan header on MoBo is set to DC mode, all connected fans will run 100% since they get the full power directly from PSU, without any voltage control.

To control 4-pin PWM fans;
* fan needs full +12V at all times
* fan needs PWM signal, which then adjust the fan speed

To control 3-pin DC fans;
* fan needs ~5V-12V
* fan speed is directly linked to how much power it receives
Note: 4-pin fans can be controlled by voltage regulation as well (DC mode)

Since your Arctic fan hub doesn't offer any voltage control method, all 3-pin fans hooked to it will run 100% at all times. And if you have issues with PWM signal (e.g no PWM signal), 4-pin fans will also run at 100%.


Yes, this is one option. Getting the revised Phanteks hub (the one that supports up to 7x fans) also gives you Manual control method (via wired remote), if you don't want to rely solely on MoBo control.
Ahh okay, sounds like i might aswell buy 4 new Arctic PWM fans, since then all my fans will be PWM and i should be able to control them from my computer.

Thanks a lot for this clarity - hope i will be able to solve it now!
 
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Actually, the ideal solution for you is the new advanced design of the Phanteks Universal Fan Controller model PH-PWHUB_02. That's the SECOND of their units recommended by Aeacus above. Here's background.

The ONLY way to control the speed of a 3-pin fan is by varying the VOLTAGE supplied to it from mobo header Pin #2. For a 4-pin fan the system is different. For that type, Pin #2 always is a full +12 VDC, and Pin #4 supplies the PWM signal to the fan. The fan itself contains a special chip that uses that signal to modify the flow of power from the fixed +12 VDC supply through the windings to alter the fan speed. If you plug a 3-pin fan into a header using that newer 4-pin signal mode, it receives a constant +12 VDC power supply from Pin #2 and gets NO signal from Pin #4 (it does not connect to that) and could NOT use that, anyway - it does not have the chip! So that fan always runs full speed.

MOST HUBS on the market connect the Ground (Pin #1) and PWM (Pin #4) lines from the mobo header to ALL their outputs to fans, so they all get the PWM signal. They connect a +12 VDC supply line from the PSU (direct connection to the PSU by a separate cable) to Pin #2 of ALL their fan outputs, so they all get that. The connect the Pin #3 line of only ONE of their outputs back to the mobo - this line sends one fan's speed signal to the mobo header for speed reading. So a HUB duplicates all the proper signals for a 4-pin fan, but can NOT vary the Voltage on Pin #2 to be able to control a 3-pin fan.

What is unique about the Phanteks Universal Fan Controller is that it adds two extra features. First, is has BOTH 3-pin and 4-pin output sockets, and each group IS fed the CORRECT signals for that fan type. To do this, the Phanteks unit "translates" the PWM signal it gets from the mobo header into a VOLTAGE control signal on Pin #2 of those 3-pin output ports. Thus this particular Hub CAN handle BOTH 3-pin and 4-pin fans properly at the same time! Just what you need with your mix! The second extra (you do not need this) is that it also CAN accept as input from a mobo the signal set from a 3-pin header. Then it "translates" that varying voltage signal from Pin #2 into a PWM signal to send out on Pin #4 of each of its 4-pin ports. In this way it truly is "Universal" because it can use either type of input signal from a mobo, and can control both types of fans simultaneously.

Now there remains a smaller issue. You have six 4-pin fans and that Phanteks Hub has four 4-pin output ports. Likewise, you have four 3-pin fans and the Hub has only three such ports. For both of these the solution is that you need a SPLITTER, but of slightly different types. A Splitter is simpler and different from a HUB because it does NOT get any power for its fans from the PSU. It only connects its fans in parallel to the host port, and all power for those fans comes from the port. So for the 4-pin fans and ports you need one like this


that's a 2-pack and you can use one of them to connect three of your 4-pin fans to one of the Hub's 4-pin output ports. The gets you six 4-pin fans.

For the 3-pin fans the small issue is that the output ports are recessed in holes in the Hub case and those holes are not wide enough to use another Splitter like the one above, even though it could work electrically. So you need a 3-pin version of a Splitter, and those are getting hard to find. But here is one set of two


Use one to connect two of your 3-pin fans to one 3-pin output of the Hub, and you can handle all four 3-pin fans.

There are limits on doing this and they ALL are met with no problem. To start with, although the fan makers here may not tell you the max current each fan can use, almost all fans like this draw from 0.10 to 0.25 A max each. When you use a Splitter to connect several fans to a single header, you must use those specs to calculate the total load on the header used. For the Phanteks hub its specs say that each output port can supply up to 1.0 A current. My proposal above says two or three fans on one header, and that certainly does not exceed 1.0 A. The Hub specs also say the limit on the TOTAL power for ALL ports of the hub is 48 W - at 12 VDC, that is 4.0 A max total. You need to connect to the Hub 10 fans, so that's sure to be less than 2.5 A current. Again, no problem.

Bottom line, you do NOT need to replace a bunch of fans or your mobo. You DO need a different fan HUB - the Phanteks Universal Fan controller - and two sets of particular Splitters.
 
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Actually, the ideal solution for you is the new advanced design of the Phanteks Universal Fan Controller model PH-PWHUB_02. That's the SECOND of their units recommended by Aeacus above. Here's background.

The ONLY way to control the speed of a 3-pin fan is by varying the VOLTAGE supplied to it from mobo header Pin #2. For a 4-pin fan the system is different. For that type, Pin #2 always is a full +12 VDC, and Pin #4 supplies the PWM signal to the fan. The fan itself contains a special chip that uses that signal to modify the flow of power from the fixed +12 VDC supply through the windings to alter the fan speed. If you plug a 3-pin fan into a header using that newer 4-pin signal mode, it receives a constant +12 VDC power supply from Pin #2 and gets NO signal from Pin #4 (it does not connect to that) and could NOT use that, anyway - it does not have the chip! So that fan always runs full speed.

MOST HUBS on the market connect the Ground (Pin #1) and PWM (Pin #4) lines from the mobo header to ALL their outputs to fans, so they all get the PWM signal. They connect a +12 VDC supply line from the PSU (direct connection to the PSU by a separate cable) to Pin #2 of ALL their fan outputs, so they all get that. The connect the Pin #3 line of only ONE of their outputs back to the mobo - this line sends one fan's speed signal to the mobo header for speed reading. So a HUB duplicates all the proper signals for a 4-pin fan, but can NOT vary the Voltage on Pin #2 to be able to control a 3-pin fan.

What is unique about the Phanteks Universal Fan Controller is that it adds two extra features. First, is has BOTH 3-pin and 4-pin output sockets, and each group IS fed the CORRECT signals for that fan type. To do this, the Phanteks unit "translates" the PWM signal it gets from the mobo header into a VOLTAGE control signal on Pin #2 of those 3-pin output ports. Thus this particular Hub CAN handle BOTH 3-pin and 4-pin fans properly at the same time! Just what you need with your mix! The second extra (you do not need this) is that it also CAN accept as input from a mobo the signal set from a 3-pin header. Then it "translates" that varying voltage signal from Pin #2 into a PWM signal to send out on Pin #4 of each of its 4-pin ports. In this way it truly is "Universal" because it can use either type of input signal from a mobo, and can control both types of fans simultaneously.

Now there remains a smaller issue. You have six 4-pin fans and that Phanteks Hub has four 4-pin output ports. Likewise, you have four 3-pin fans and the Hub has only three such ports. For both of these the solution is that you need a SPLITTER, but of slightly different types. A Splitter is simpler and different from a HUB because it does NOT get any power for its fans from the PSU. It only connects its fans in parallel to the host port, and all power for those fans comes from the port. So for the 4-pin fans and ports you need one like this


that's a 2-pack and you can use one of them to connect three of your 4-pin fans to one of the Hub's 4-pin output ports. The gets you six 4-pin fans.

For the 3-pin fans the small issue is that the output ports are recessed in holes in the Hub case and those holes are not wide enough to use another Splitter like the one above, even though it could work electrically. So you need a 3-pin version of a Splitter, and those are getting hard to find. But here is one set of two


Use one to connect two of your 3-pin fans to one 3-pin output of the Hub, and you can handle all four 3-pin fans.

There are limits on doing this and they ALL are met with no problem. To start with, although the fan makers here may not tell you the max current each fan can use, almost all fans like this draw from 0.10 to 0.25 A max each. When you use a Splitter to connect several fans to a single header, you must use those specs to calculate the total load on the header used. For the Phanteks hub its specs say that each output port can supply up to 1.0 A current. My proposal above says two or three fans on one header, and that certainly does not exceed 1.0 A. The Hub specs also say the limit on the TOTAL power for ALL ports of the hub is 48 W - at 12 VDC, that is 4.0 A max total. You need to connect to the Hub 10 fans, so that's sure to be less than 2.5 A current. Again, no problem.

Bottom line, you do NOT need to replace a bunch of fans or your mobo. You DO need a different fan HUB - the Phanteks Universal Fan controller - and two sets of particular Splitters.
Thanks for this detailed answer! I understand that the splitter and Phantek fan hub would solve my problem with my current fans. But as i can read from all these answers, replacing my 4 NZXT fans with Arctic PWM fans, as the other 6 fans i have, would also solve my problem? Since then all my fans would be PWM and i should be able to control them?
The thing is, buying 4 new Artic fans would be cheaper for me then buying the Phantek fan hub. And if i need 4 splitter cables it would be even more expensive then the 4 Artic fan.
 
Ah, if the new fan cost is lower, then surely that is a good plan. What I suggested will work. You CAN control the speed both of 3-pin and of 4-pin fans IF you arrange to use the correct set of signals for each. That is what the Phanteks Hub can do. But for cost reasons, the all-4-pin plan is better.
 
I built my pc in the NZXT H9 flow tower which comes with 4 fans and then i bought 6 extra Arctic F12 fans.
Can you show a photo of your system with side panel removed?
10 fans seem excessive.
What are full hardware specs of your system?

Anyway - you could connect 4pin fans to fan hub and
3pin fans directly to motherboard. You would need to configure motherboard fan headers to DC mode though.
 
Listen to Paperdoc, he is BY FAR the most knowledgeable contributor here when it comes to fan and fan controller technology. I know a fair amount, as do others here, but I don't think any of us are in the same class as he is. So it would be wise to listen to what he suggests.