Dell Precision 7540 and 7740 Owner's Thread

Hi !

See picture in this post for reference:
http://forum.notebookreview.com/thr...0-owners-thread.820539/page-202#post-10883267

Are the boxes grayed out or are you actually able to change those values (PL1,PL2,Tau) ?
If the latter is correct, even if you click "ok" to confirm your modified values, when you reopen that section will stock values be displayed once again ?

If you use hwinfo, could you please share a screenshot like this ?
https://www.oldergeeks.com/downloads/gallery/HWiNFO64_main_2.png

I want to see whether [Unlocked] is being reported or not at "CPU Power Limit 1 (long duration)" and at "CPU Power Limit 2 (short duration)"

I thought Dell would let us change both multiplier and power limits on HK cpus.

Were the power limits locked even for 8950hk on 7530/7730 ?

 

Everything looks OK: in throttlestop you can set the power limits and in hwinfo are reported as they should be, BUT if you try for example cinebench you can see (with throttlestop open) that the real power limits are still 107W and 75W with 28 sec duration for power boost as they are by default from Dell.

 

Where do you see current power limits ?
Looking at "PKG Power" value (for instance 10.5 W like in the following picture)


or using any other software ?

Could you use HWInfo Sensor Status (see this as reference:
https://www.51nb.com/d/file/p/20190912/56a7f693c57e2cc03a3b17e0ab0c2687.png)
to see if your modified PL2 and PL1 values are correctly displayed ?
As you can see from the above picture taken from the 7740 review by 51nb forum, stock values are the same you previously said.

Would it be possible for you to post a screenshot of hwinfo sensors showing CPU Package Power, Total System Power, PL1 and PL2 values while you're running cinebench (single and multi tests) or TS bench (1 thread test and 16 threads test) ?

One more thing: What if you try to set both PL1 and PL2 below stock values ?
Let's say: PL2=42 W; PL1=35 W
With these new values, if you run a 16 threads TS bench you will see PKG going over 35 W anyway (up to stock 75 W) as any type of change is rejected by dell fw limitation, right ?

 

Yes, and also checking the "throttle" indication that turn on when system is limiting at 75W.

Seems like the power issue is an 'upper cap', downward you can set a lower limit and it works, upward there are the Dell's thresholds that have the maximum priority over any software settings.
And this also make sense in order to use these thresholds as safety limits for power supply subsystem (then we can talk about the fact that maybe there was a little more room to use, but..)

 

Let's suppose you run a 16 threads TS bench test and you have no thermal issues throughout the whole test.

As soon as PKG Power displays 107W, PL2 box under "core" will change its background color from yellow to red for 28 seconds.
After this span of time, PL2 color box goes back to yellow and simultaneously PL1 color box goes from yellow to red till the end of the stress test. Is it correct ?

So you have actually tried on your unit those values i previously suggest you (PL2=42 W; PL1=35 W) and you did actually observed that PKG Power value never went above 42W during those 28 seconds and never above 35W on the long run, right ?

One more thing: could you also check if your modified values also appear on hwinfo sensors under CPU Package Power, Total System Power, PL1 and PL2 values ?
For instance in this picture you can see stock pl2=107W and pl1=75W
https://www.51nb.com/d/file/p/20190912/56a7f693c57e2cc03a3b17e0ab0c2687.png
Just wondering if even those ones change to those you modified through TS.

 

No, 107W is short time power limits and power throttling kick-in almost immediately when you reach this value, so PL2 and EDP OTHER switch to red every time system is try to go over 107W.

After 28 sec, long time power limits kick-in so PL1 (75W) and EDP OTHER switch to red till the end of the test or benchmark / whatever.

No, I tried with PL2 65W and PL1 35W and I observed that also the timer works correctly with value >28 sec. The problem is when system goes over 75W, that you can stay over that at max for 28 sec, regardless the setted value for timer nor you can go over 107W as PL2.

With bios 1.3.3 and hwinfo last version (6.13.3955) there are no PL1 and PL2 values under sensors. But in the cpu info there are still the right setted up values.

Btw, trust me, >75W for max 28sec and 107W as maximum cap are the limits (at least for the actual version of Dell bios and ThrottleStop). I did test for days to find the best solution..

 

Quick note:

I see Dell is offering up to 64GB DDR4-3200 now.

 

The embedded controller (EC) likely imposes an upper limit which will silently override whatever PL1 / PL2 is set to. You may be able to get around it by using an EFI tool to set the IMON offset / IMON slope bios values to trick the EC into thinking a lower value is being drawn. This will skew results in monitoring tools as well but the performance will definitely increase. I had to do this with an earlier firmware version on the MSI WT75 to go above 91W TDP. Before doing this you would want to visually inspect the motherboard and make sure the VRM can actually handle that amount of load.

 

This is really interesting. Do you have any link or guide about that?
What's the situation with your 7740?

EDIT: after a quick search seems like only in MSI notebook there's an easy way to do the trick

 

I guess Dell has 64GB 3200Mhz RAM listed for one month or so, but up to version 1.4.0 the flickering problem has not been solved yet.
At least for me I have to add a 2666 stick to force the other three 3200 sticks to work at lower speed. I contacted support but got no response.
I wonder how the configurations with 3200MHz RAM would ever work and which sticks Dell is using.