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kjoiner

1 Message

1795

April 8th, 2021 05:00

Dell 7550 throttling - inconsistent behavior

Hello,

I've seen some other posts regarding throttling issues with Dell 7550s and Thunderbolt docking stations.  I think mine is similar but with some other details.  My system is a 7550 connected to a Thunderbolt WD19TB docking station.  In my case, the throttling is inconsistent.  In all cases the docking station is plugged in:

1.  System boots up and is throttled.  Plugging in the power adapter solves the problem

2.  System boots up and is throttled.  Plugging in the power adapter doesn't work but then unplugging it does

3.  System boots up with power adapter plugged in and is throttled.  Unplugging it solves the problem

4.  System boots up with power adapter plugged in an works fine.

Right now, my only tool is to keep the Windows performance tab open in task manager to see if the CPU is being throttled and then plug in and unplug the power adapter to see what works.

This is very strange.  I've had our IT department look at it but as mentioned above, the behavior keeps changing.

 

Is the issue with the docking station?  In the other post, a WD19DC station was mentioned.

 

Thanks,

Kyle

 

 

 

JimiScott

1 Rookie

 • 

21 Posts

April 29th, 2021 02:00

Kyle, I assume it's throttling down to about 0.84Ghz.

There seems to be an issue, which Dell seems not to acknowledge.

When there's a thunderbolt attached, the system will throttle down under some circumstances. I have found the throttling is triggered when there is a certain type of device (in my instance it's a phone) plugged into the thunderbolt device.

I have raised this with Dell...no real response.

Captain_Dave

1 Message

May 19th, 2021 07:00

have this issue across our fleet.  Downgrade BIOS to 1.3 and it will work.

cpuchip

16 Posts

July 9th, 2021 09:00

I just experienced this with my Dell Precision 7550 and a WD19TB dock after updating both to the latest firmware. I'm running 1.8fw on my precision. the dock firmware is

MST: 05.04.06 ; Gen1 Hub 01.21 ; Gen2 Hub 01.47 ; NVM 60.00 ; Ec 01.00.00.05

If you install something like Intel Power Gadget or HWINFO you can see if the PROCHOT flag is being thrown.... It is on my system.

you could probably use throttle stop to disable BD PROCHOT (Bi-directional PROCHOT) I suspect that since this laptop wants 180w power supply and the WD19TB only provides 130w that the firmware designers decided to inconsistently throw the PROCHOT flag to throttle the system down to stay within a 130 w power envelope, as apposed to just setting the P1 or P2 power thresholds on the processor.... It's a LAME way to throttle, I've had similar experiences with the 7540 and the Microsoft SurfaceBook 2.

cpuchip

16 Posts

July 9th, 2021 09:00

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