Precision 7540 & Precision 7740 owner's thread

[Zeht]

1 minute ago, PHVM_BR said:

I believe we discovered the culprit: it's the absence of the battery!

It may be. I bought the machine from ebay a few weeks back, I'm not from the US so I imported it to my country, meaning that I can't return it now. So, I'm stuck with this laptop since I sold my old zbook 15 g2.

I was going to get a battery eventually but now I'm not sure, I would have to spend $100 to get it into my country and the laptop may continue performing like crap.

[Zeht]

6 minutes ago, Aaron44126 said:

Are you using 180W or 240W power adapter?  Do you have a 240W that you could try?

I'm using a 180W adapter, unfortunately I can't get a 240W. Either way I think 180W should be more than enough, the quadro takes around 80W and the cpu 45W. If updating the bios doesn't work I will try flashing the max-q version vbios, which has a 60W tgp if I recall correctly.

[PHVM_BR]

8 minutes ago, Zeht said:

and the laptop may continue performing like crap.

I seriously believe it's the lack of battery.

 

Many systems, especially with dGPU, limit heavy usage when there is no battery connected.

 

In ultra performance, your laptop should maintain at least 45W on the CPU simultaneously with the GPU.

 

In fact, I believe that the default behavior of this machine is for the CPU power to fluctuate between 60 and 45W (depending on temperatures) while the GPU consumes its 80W.

 

My original system had an i7-9750H and Quadro T2000 and the behavior at full load CPU + GPU was the i7 varying between 60 and 75W while the GPU maintained 60W (its maximum TGP).

 

In the case of RTX 3000 or higher, this CPU limit is lowered as the GPU consumes more (80W).

[Zeht]

6 minutes ago, PHVM_BR said:

I seriously believe it's the lack of battery.

 

Many systems, especially with dGPU, limit heavy usage when there is no battery connected.

 

In ultra performance, your laptop should maintain at least 45W on the CPU simultaneously with the GPU.

 

In fact, I believe that the default behavior of this machine is for the CPU power to fluctuate between 60 and 45W (depending on temperatures) while the GPU consumes its 80W.

 

My original system had an i7-9750H and Quadro T2000 and the behavior at full load CPU + GPU was the i7 varying between 60 and 75W while the GPU maintained 60W (its maximum TGP).

 

In the case of RTX 3000 or higher, this CPU limit is lowered as the GPU consumes more (80W).

When I bought the laptop the seller said that he removed the battery due to "Communication error". I'm afraid that ths embedded controller might be faulty and a new battery will either not work or the issue with power throttling might continue.

 

I updated to the latest 1.30.0 bios and the problem persists, undervolt seems to still be working. I'm tired of this machine, later I will try flashing the maxq vbios and see if it fixes anything.

[Zeht]

Well I tried flashing a 65W max-q vbios but it kinda bricked the laptop, it would boot into windows but as soon as the login screen appeared the screen would turn black. I had to use the safe mode to flash the original vbios and it's working back again.

 

Before getting a battery I want to make sure it will fix the issue. Could anyone with a precision 7540 unplug their battery and run a gpu+cpu stress test?, I want to see if the cpu throttling behavior is normal in this machine or if mine is faulty.

[Chalybion]

I can check with my 7540 in a couple of days, if no one else has by then.

I had a similar "communication error" with a battery that had completely discharged and left in that state for several years.  Replacing the battery fixed that issue.  I didn't stress test in that state, though.

[PHVM_BR]

6 hours ago, Zeht said:

Could anyone with a precision 7540 unplug their battery and run a gpu+cpu stress test?

Tomorrow I'll try to test and post the results here.

 

See the screenshot of the ~14 minute test I did simultaneously using the AIDA64 CPU Stress + Heaven still with i7-9750H / RTX 4000 (90W VBIOS) / original Dell thermal paste from the new heatsink / no undervolt:

 

 

 

[Zeht]

Yesterday I tried repasting since I noticed the cpu vrm would get into the 70°s (Dell EC temp1 in hwinfo). I change the thermal pad for a slightly thicker one and now it stays in the 60°s but the issue persists. I'd really appreciate if someone could do the tests without battery, I'm going crazy with this laptop

[PHVM_BR]

On 3/23/2024 at 7:27 AM, Zeht said:

Yesterday I tried repasting since I noticed the cpu vrm would get into the 70°s (Dell EC temp1 in hwinfo). I change the thermal pad for a slightly thicker one and now it stays in the 60°s but the issue persists. I'd really appreciate if someone could do the tests without battery, I'm going crazy with this laptop

The problem is definitely the lack of battery.

 

I did the test without battery running AIDA64 CPU test + Heaven.

 

With BD PROCHOT the CPU worked inconsistently, varying between ~15 and 30W while the GPU also fluctuated, unable to maintain a constant ~90W.

While the tests were running, the BD PRO alert flashed red constantly in the ThrottleStop main window.

 

By unchecking BD PROCHOT, the GPU started to work apparently normally, while the CPU continued to oscillate strongly, but with higher power levels, between ~15 and 60W, mainly between ~20 and 50W.

This time the POWER alert flashed red constantly.

 

 

[Zeht]

9 hours ago, PHVM_BR said:

The problem is definitely the lack of battery.

 

I did the test without battery running AIDA64 CPU test + Heaven.

 

With BD PROCHOT the CPU worked inconsistently, varying between ~15 and 30W while the GPU also fluctuated, unable to maintain a constant ~90W.

While the tests were running, the BD PRO alert flashed red constantly in the ThrottleStop main window.

 

By unchecking BD PROCHOT, the GPU started to work apparently normally, while the CPU continued to oscillate strongly, but with higher power levels, between ~15 and 60W, mainly between ~20 and 50W.

This time the POWER alert flashed red constantly.

 

 

 

 

Well case closed, I'll get a battery soon. Thanks a lot for your time, I really appreciate it.

[htfan]

Are the Thunderbolt/USB-C ports on the 7740 always on/powered?

 

Just bought a 4-port USB-C hub and noticed that when the laptop is powered off the light on the new hub remains on.  So the two ports are always powered?  Is that expected behavior?  And can I change that?

 

BTW, the AC adapter is plugged in.  Pretty much always is, this is used as a desktop replacement.

 

Thanks!

[Aaron44126]

6 hours ago, htfan said:

Are the Thunderbolt/USB-C ports on the 7740 always on/powered?

 

Yes, the USB ports are powered on even if the system is powered off.  I believe there is an option in the BIOS called "USB powershare" which might control this — I just leave it on as that is the preferred behavior for me.  (You can actually use the system as a giant USB battery even if the AC adapter is not plugged in, i.e. to charge your phone while traveling.)

[htfan]

5 hours ago, Aaron44126 said:

 

Yes, the USB ports are powered on even if the system is powered off.  I believe there is an option in the BIOS called "USB powershare" which might control this — I just leave it on as that is the preferred behavior for me.  (You can actually use the system as a giant USB battery even if the AC adapter is not plugged in, i.e. to charge your phone while traveling.)

Got it, thanks for the info!

[PHVM_BR]

I purchased a 240W Alienware SFF (GaN) power adapter and it works great on the Precision 7540.

 

As before with the original 180W power adapter at full CPU + GPU cross-load, the i9-9980HK remained at ~60W and the RTX 4000 at ~90W but now there is no more battery drain.

 

The system works by consuming ~150W from the CPU and GPU simultaneously, around ~180/190W in total, without discharging and without thermal throttling.

Impressive!

 

I'm very pleased with the new investment (i9 / RTX 4000 / 240W adapter).

[Chalybion]

I need help getting my undervolt back...

I am on BIOS v1.26.1/Windows 11 23H2, and had to replace the CMOS battery.  When restarting, I reset all BIOS settings to how they were, including disabling Intel virtualization settings.  The overclocking lock and overclocking feature are both set to 0x1.  I opened throttlestop, and voltage controls are disabled...

 

I read earlier in the thread how BIOS 1.7.0 is the magic one for consistently enabling undervolts; the problem is that Dell's Support page only has 1.3.3 (can't downgrade past 1.5.1 because different memory map I think?)  and 1.8.2.  Additionally, 1.24 was the last BIOS that allows downgrading - I can get around that if need be, but it's more involved...

 

Any thoughts or sure-fire solutions?

[PHVM_BR]

2 hours ago, Chalybion said:

Any thoughts or sure-fire solutions?

Have you tried restoring factory settings in BIOS?

 

If your laptop left the factory with BIOS 1.7 or lower this is enough to restore the possibility of undervolt.

 

Otherwise, the option is to edit the variables (very simple).

[Chalybion]

6 hours ago, PHVM_BR said:

Have you tried restoring factory settings in BIOS?

 

If your laptop left the factory with BIOS 1.7 or lower this is enough to restore the possibility of undervolt.

 

Otherwise, the option is to edit the variables (very simple).

I tried both, and they didn't work with the current BIOS.  I did try upgrading one BIOS version to v1.27.0, then resetting to factory defaults, and then voltage/frequency controls came back.  No idea why - just a bit frustrating.

[PHVM_BR]

2 hours ago, Chalybion said:

I tried both, and they didn't work with the current BIOS.  I did try upgrading one BIOS version to v1.27.0, then resetting to factory defaults, and then voltage/frequency controls came back.  No idea why - just a bit frustrating.

BIOS defaults return the configuration of the installed BIOS.

If the installed version is anything above 1.7.0 this will block the undervolt.

 

Factory Defaults returns the original factory BIOS configuration.

If the original BIOS is 1.7.0 or lower this option will unlock the undervolt. If it is 1.8.2 or higher, this option will block undervolt if it is unlocked.

[Chalybion]

Yep, I followed your advice and understand what you are saying.  The purpose of my post was to share an experience where, counterintuitively, the factory reset didn't work on my current BIOS version (1.26.1), but the factory reset did work after I upgraded to v1.27.0

[Will]

Hello guys, do you know where can i find that RTX 4000 110W vBIOS for Precision 7740 please?

[PHVM_BR]

On 6/30/2023 at 7:04 PM, Chalybion said:

Overclocking Feature:  setup_var Setup 0x856 0x1

 

What exactly does this?

 

I unlocked it out of curiosity and my i9-9980HK clocks were stuck at 800MHz.

 

To unlock undervolt and increase ratios this is not necessary, what does it do?

[meowpressreturn]

Thought I'd post some intimate under the casing pics from my 7540 here as I was poking about in there today. I'm thinking of once again replacing the SSD in my daily driver Precision 3551 with a bigger and hopefully cooler one.  SDDs come in many sizes but always leave in one size (full) 😛

 

Which means that solid state heater the 3551 has (1 TB Samsung 970 EVO Plus, the older model with the Phoenix controller) will end up in here. Since that still leaves me a vacant slot maybe I'll throw in the 512 GB Kioxia my 3551 originally came with as well, assuming two years in the back of a cupboard haven't killed it already. See how.

 

Interesting to see that the 7540's metal plates for the SSD come with an adhesive thermal pad (unlike the 3551's SSD plate  edit: the 3551 SSD plate DOES have a thermal pad but I still got terrible terrible temps with the Samsung SSD in the 3551, whereas the SK Hynix SSD in my 7540 is practically cold! ).

 

That sticky thing with the "Laird" label IS a thermal pad right?

 

 

If I'm putting in an SSD in there or more RAM in those DIMM slots, will I need to remove those plastic label things?

 

I should probably open the casing and deal with dust more often, although, even with that dust, and unlike every other Dell laptop I've ever owned, the 7540 actually seems to have reasonable cooling (in contrast, the 3551's idea of cooling is an absolute joke).

 

 

 However every time I open that case I lose another little plastic clippy thingy 😞

 

Edited September 12 by meowpressreturn
Correction about thermal pad in 3551

[Aaron44126]

12 minutes ago, meowpressreturn said:

If I'm putting in an SSD in there or more RAM in those DIMM slots, will I need to remove those plastic label things?

 

No, those will fit under the SSD/DIMM and not cause any problem.

[Chalybion]

On 4/25/2024 at 4:36 PM, PHVM_BR said:

What exactly does this?

 

I unlocked it out of curiosity and my i9-9980HK clocks were stuck at 800MHz.

 

To unlock undervolt and increase ratios this is not necessary, what does it do?

I'm not certain, honestly.  I enabled it because I thought it went along with the overclocking lock.  When I updated BIOS, I actually had to disable the Overclocking Feature to get Throttlestop voltage controls to return.

 

An FAQ in an Alienware BIOS says that the Overclocking Feature allows the CPU to adjust:

- Flex Ratio and Voltage in a Turbo Mode environment

- Core ratio limit

- Core voltage

- Long duration PWR limit

- Short duration PWR limit.

 

Perhaps the Overclocking Feature is necessary to go above 5 GHz?  (Though that is a bad idea in the laptop form factor)

 

In other news, I found that the BIOS settings for PL1 Enable, PL1 Power, PL1 time limit do change the values in the MSR.  However, the Dell Embedded Controller still overrides the MSR if the EC power limit is lower.

 

I was able to replicate your result of disabling the EC power limits by making changes in Throttlestop, then sleeping and resuming from sleep.  It was somewhat random, and I don't know the exact steps.

[Chalybion]

General thoughts on the Precision 7540 after using one for a year:

I still love the good keyboard, good touchpad with nice physical buttons, solid build quality, and ease of maintenance.  The LP156QHG screen is a moderately easy upgrade to a high color gamut / high refresh rate screen that improves quality of life.  The processor and graphics cards are still reasonable competitive for productvity and gaming at mid-range settings, though a bit power hungry.  In newer laptops, the Ryzen 7840U provides slightly better CPU (vs. 9980HK) and comparable GPU to the T1000, all while using less than a third of the power - that would be really attractive in a Precision build package.