Precision 7540 & Precision 7740 owner's thread

[PHVM_BR]

3 minutes ago, Aaron44126 said:

 

That is not too bad a price as far as new motherboards with a high-end CPU go.  Only you can decide if it is "worth it".

 

Motherboard replacement is not a difficult job (if you're already comfortable with a repaste), just a time-consuming one.  I replaced the motherboard in my Precision M6700 once and it took me an hour or so.  Just follow the steps in the service manual and set up something to keep your screws organized.

If I really go ahead and have any difficulties along the way, I'm asking for help!

 

Thanks again!

[Kitje]

Back currently sore from getting to these components. They really do not want end users replacing these fans... And I did discover this; the impellers on Deltas are removable when Sunon ones aren't.

[PHVM_BR]

If I change the motherboard I will take advantage and change the thermal pads.

Despite having experience changing thermal paste, I never changed the pads.

Does anyone have an indication of the thickness of the pads on the Precision 7540?

What are the best ones I can use?

[Kitje]

27 minutes ago, PHVM_BR said:

If I change the motherboard I will take advantage and change the thermal pads.

Despite having experience changing thermal paste, I never changed the pads.

Does anyone have an indication of the thickness of the pads on the Precision 7540?

What are the best ones I can use?

Not sure which maker to recommend, but if you're buying pads then get a set of different thicknesses. I compare them to the set I have and cut accordingly when the thicknesses match.

 

[PHVM_BR]

6 minutes ago, Kitje said:

Not sure which maker to recommend, but if you're buying pads then get a set of different thicknesses. I compare them to the set I have and cut accordingly when the thicknesses match.

 

maybe 1, 1.5 and 2mm...

[Kitje]

1 hour ago, PHVM_BR said:

maybe 1, 1.5 and 2mm...

If I had a tool to measure everything on mine I would, but I did it through visual.

 

If in doubt of what you really need, a set of them in different thicknesses will suffice. Mine are from Adwitz and they're alright. Cheap but alright.

 

Unrelated, but I ran my 7540 in the BIOS and waited for the fans to kick in, and I don't actually hear the whistle as much. I think they're gonna be keepers. It's still there but not as loud, so that's something positive.

[PHVM_BR]

54 minutes ago, Kitje said:

If I had a tool to measure everything on mine I would, but I did it through visual.

 

If in doubt of what you really need, a set of them in different thicknesses will suffice. Mine are from Adwitz and they're alright. Cheap but alright.

 

Unrelated, but I ran my 7540 in the BIOS and waited for the fans to kick in, and I don't actually hear the whistle as much. I think they're gonna be keepers. It's still there but not as loud, so that's something 

Mine probably has that whistling sound you report, but it only occurs when the fans turn up to a high level, for a short period.

If I really go ahead and change the motherboard I'll remember and post some pictures of the fans.

[Kitje]

Well, it's properly put together again and actually there is a difference already. More than significant now. However, since replacing the paste I still need to see if there arent any thermal issues when I'm in Windows. I'll do it tomorrow running Unreal or running Vegas like normal with Throttlestop.

 

I'm relieved, for now.

[Kitje]

On 2/13/2023 at 8:43 PM, Aaron44126 said:

Most Precision laptop models have multiple fan models in the mix.  I found this photo of Delta fans (Precision 7530 and 7540 fans are interchangeable).  Here's an old thread about the different types of fans available for the Precision M4800 (see posts by @unnoticed).  I ended up sourcing Delta CPU and GPU fans for my Precision M6700 after seeing those posts; Delta was preferred back then, but I'm not sure if that's still the case in Precision 7X40; in Precision 7770, Sunon is generally preferred over Delta.

 

If you do buy aftermarket fans, you should check with the seller because there is no real guarantee that the fan model pictured is the same model that you will get.

 

I personally use ANC headphones when gaming, fan noise becomes a non-issue.  (I take steps like disabling turbo boost to limit the fan noise when I'm not running an intensive application.)

Ever since replacing Sunon with those Deltas, seems that most likely preference are Deltas over Sunon for 7530/7540. Shame really because these systems with Deltas aren't common. I'm sure they're not common.

 

I've repasted too, and since I do not really care for a lot of performance I'm either on Balanced for better battery and on Quiet for Dell Power Manager. I've left turbo on so if performance IS needed then the steps going beyond turning that off now means Deltas are a must.

 

 

[Kitje]

Question: Do these brackets allow panels that don't need to be adhered on be mounted to the lid through screws? https://www.parts-people.com/index.php?action=item&id=29538

 

Since from the looks of it, the top and bottom provide screw holes so... Thinking about it now had I got a different lid with these installed I wouldn't have had to borderline give myself a stroke trying to install a new LCD. 🤨

[Aaron44126]

7 hours ago, Kitje said:

Question: Do these brackets allow panels that don't need to be adhered on be mounted to the lid through screws? https://www.parts-people.com/index.php?action=item&id=29538

 

Most panels that mount with screws have such brackets on them (the panel itself doesn't have the screw holes); whether it will be compatible with your lid depends on if there are "receptors" for the screws in the right place.  (I have pulled panels for Precision 7510, 7530, and 7560 that were all mounted in such a way which is why I was surprised to find that Precision 7540 uses adhesive for the panel.)

[Kitje]

8 hours ago, Aaron44126 said:

 

Most panels that mount with screws have such brackets on them (the panel itself doesn't have the screw holes); whether it will be compatible with your lid depends on if there are "receptors" for the screws in the right place.  (I have pulled panels for Precision 7510, 7530, and 7560 that were all mounted in such a way which is why I was surprised to find that Precision 7540 uses adhesive for the panel.)

I think these brackets add them, they also have those alignment pins. I can't really tell but I'm not sure if it's a revision thing. Fans for example being Delta then Sunon and then the mounting of the LCDs being different. Maybe whatever they have had in stock would depend on what you got in the laptop.

[Aaron44126]

6 minutes ago, Kitje said:

I think these brackets add them

 

The bracket will just have a hole where the screw goes, but it won't help affixing your panel to the chassis unless the chassis itself also has a place for the screw to go in.

[Kitje]

44 minutes ago, Aaron44126 said:

 

The bracket will just have a hole where the screw goes, but it won't help affixing your panel to the chassis unless the chassis itself also has a place for the screw to go in.

Difficult to compare and confirm, since the part picture I looked at doesn't have the kind of brackets I had to deal with. I think it's got the screws in the same places though.

[Aaron44126]

1 hour ago, Kitje said:

Difficult to compare and confirm, since the part picture I looked at doesn't have the kind of brackets I had to deal with. I think it's got the screws in the same places though.

 

Precision 7530 and 7540 use the same chassis so I wouldn't be surprised if that is the case.

 

...Probably more than you want to deal with, but it occurs to me that you could probably install a Precision 7530 "display assembly" on your Precision 7540 with no trouble at all, if it turned out that made it easier to swap around display panels.

[Chalybion]

I recently purchased a Precision 7540, and have had success tweaking the power settings of the processor using Brendan Greenley's guide:

Undervolting 2020 Dell Laptops

 

For anyone interested I've attached the BIOS dump from v1.24.  I'm currently on BIOS v1.26.1, and can confirm that the same settings work.

 

In the GRUB terminal, the relevant commands are (the forum software changes all "x'es" to multiplication signs - not sure how to fix this?):

Overclocking Lock:  setup_var Setup 0x789 0x1

CFG Lock:  setup_var Setup 0x6ed 0x1

Overclocking Feature:  setup_var Setup 0x856 0x1

 

With these changes, I was able to achieve a stable undervolt of -120 mV cache and -150 mV core on my i9-9980HK using Throttlestop.  On stock cooling, the Cinebench R20 multicore score increased from 3550 to 4060.

 

However, Dell has appeared to limit the power limits to 75W for PL1, and 107W for PL2.  Changes in Throttlestop beyond these limits do not take.

 

That's when I found this article about the ability of IMON Slope to effectively increase power limits by reporting only a percentage of the power draw to the controller:  [GUIDE] Unlock the EC TDP limit of your low power U series Intel CPU

 

The Precision 7540 BIOS does have four IMON Slope variables, which are normally set to 0x0 (disabled / power reported = actual power).  On the stock cooling, the processor already reaches thermal limits at 107W, but I wanted to increase the PL1 to improve sustained performance.  I was able to successfully change the IMON Slope to 90, making the effective PL1 (75W / 0.9) = 83W.  I also reduced the PL2 to 96W to maintain the same effective power limit.  Here are the changes I made:

 

setup_var Setup 0x8ac 0x5A

setup_var Setup 0x8ae 0x5A

setup_var Setup 0x8b2 0x5A

setup_var Setup 0x8b4 0x5A

 

As a result, the processor sustained ~3850 mhz on all cores at 90-92 °C at PL1, resulting in a Cinebench R20 multicore score of 4279!

 

I have plans to upgrade the cooling solution by re-pasting with PTM7950, replacing thermal pads, and doing the Delta fan mod mentioned elsewhere in this thread.  I have all the parts, but lack time - so I will report the improvements in a couple of months, after complete.

File_DXE_driver_Setup IFR.txt

[PHVM_BR]

3 hours ago, Chalybion said:

I recently purchased a Precision 7540, and have had success tweaking the power settings of the processor using Brendan Greenley's guide:

Undervolting 2020 Dell Laptops

 

For anyone interested I've attached the BIOS dump from v1.24.  I'm currently on BIOS v1.26.1, and can confirm that the same settings work.

 

In the GRUB terminal, the relevant commands are (the forum software changes all "x'es" to multiplication signs - not sure how to fix this?):

Overclocking Lock:  setup_var Setup 0x789 0x1

CFG Lock:  setup_var Setup 0x6ed 0x1

Overclocking Feature:  setup_var Setup 0x856 0x1

 

With these changes, I was able to achieve a stable undervolt of -120 mV cache and -150 mV core on my i9-9980HK using Throttlestop.  On stock cooling, the Cinebench R20 multicore score increased from 3550 to 4060.

 

However, Dell has appeared to limit the power limits to 75W for PL1, and 107W for PL2.  Changes in Throttlestop beyond these limits do not take.

 

That's when I found this article about the ability of IMON Slope to effectively increase power limits by reporting only a percentage of the power draw to the controller:  [GUIDE] Unlock the EC TDP limit of your low power U series Intel CPU

 

The Precision 7540 BIOS does have four IMON Slope variables, which are normally set to 0x0 (disabled / power reported = actual power).  On the stock cooling, the processor already reaches thermal limits at 107W, but I wanted to increase the PL1 to improve sustained performance.  I was able to successfully change the IMON Slope to 90, making the effective PL1 (75W / 0.9) = 83W.  I also reduced the PL2 to 96W to maintain the same effective power limit.  Here are the changes I made:

 

setup_var Setup 0x8ac 0x5A

setup_var Setup 0x8ae 0x5A

setup_var Setup 0x8b2 0x5A

setup_var Setup 0x8b4 0x5A

 

As a result, the processor sustained ~3850 mhz on all cores at 90-92 °C at PL1, resulting in a Cinebench R20 multicore score of 4279!

 

I have plans to upgrade the cooling solution by re-pasting with PTM7950, replacing thermal pads, and doing the Delta fan mod mentioned elsewhere in this thread.  I have all the parts, but lack time - so I will report the improvements in a couple of months, after complete.

File_DXE_driver_Setup IFR.txt 2.18 MB · 0 downloads

I don't understand, my Precision 7540 is still in BIOS 1.24.0 and undervolt is unlocked.

I didn't need to edit the BIOS to do a dervolt. Lock must have occurred in later version, 1.25.0...

 

The power limits are interesting, in my case with i7-9750H, PL1=75W and PL2=90W, and sometimes I manage to increase them by checking the MMIO and MSR boxes in Throttlestop. It's something random, usually blocked, but I've managed to increase them a few times and they go back to default as soon as I restart the system...

 

I have PTM 7950 applied since the beginning of the year and my undervolt is -250mV for the core and -130mV for the cache.

 

Out of curiosity I tested it without undervolt and with the power limits at 107/107W and the i7-9750H needs ~100W to run Cinebench R23 mukticore with maximum clock (4.0GHz all cores).

 

With my undervolt, which is 100% stable used since the purchase in December 2019, the consumption goes down to ~60W!

 

About PTM 7950, without undervolt and at 4.0GHz all cores during the entire test on CB R23 consuming ~100W the processor remains at 95/97°C without throttling.

With undervolt at ~60W the temperature drops by about 20°C and the fans only reach ~3900 rpm (the maximum is ~5150 rpm).

[Chalybion]

That's unexpected - "Unlock Adjustable Voltage" was disabled in Throttlestop on BIOS 1.24 until I changed those variables.  I am on Windows 11 22H2, if that makes a difference.

 

There appear to be other BIOS variables linked to PL1 / PL2 that I will experiment with to see if they can override the 75W / 107W limit.  Throttlestop lets me set values above 75/107, but the CPU will always throttle to 75/107 during a benchmark.  Turbo Time Limit appears fixed too.

 

With an undervolt, the 9980HK can sustain 4.2 GHz on all cores while consuming ~105W.  I will need upgraded thermal compound to sustain that speed reliably.  With more thermal headroom, I will experiment with the highest all-core speed that can be sustained.

[PHVM_BR]

31 minutes ago, Chalybion said:

I am on Windows 11 22H2, if that makes a difference.

I have W10 Pro 22H2 here.

 

Maybe just need to disable core isolation and virtualization features in W11 for undervolt.

[Chalybion]

33 minutes ago, PHVM_BR said:

Maybe just need to disable core isolation and virtualization features in W11 for undervolt.

They are disabled already; my understanding is if they are enabled in W11, then all voltage register changes are locked out, even if enabled in the BIOS.  People who require W11, virtualization, and undervolting have had limited success either setting the undervolt in BIOS, or writing code that applies an undervolt each boot before Windows loads.

[PHVM_BR]

11 hours ago, Chalybion said:

They are disabled already; my understanding is if they are enabled in W11, then all voltage register changes are locked out, even if enabled in the BIOS.  People who require W11, virtualization, and undervolting have had limited success either setting the undervolt in BIOS, or writing code that applies an undervolt each boot before Windows loads.

If you disabled core isolation/virtualization and it was still blocked it maybe that restoring factory defaults in BIOS would unlock undervolt.

 

From a certain version of the BIOS, very old, it was necessary to restore the factory defaults to unlock the undervolt.

 

Here without editing the BIOS the undervolt works on 1.24.0.

If there really is a block it must have started in BIOS 1.25.0 or 1.26.1....

[Aaron44126]

There was some trick to do factory reset and get undervolt back after upgrading to a newer version of the BIOS that blocked it. Maybe you just figured out a “more specific” way to accomplish the same thing …

[TunaDog]

Hi there.  My 7740 has been working well enough that I only today learned that notebookreview is gone.  What a shame.

 

I am trying to upgrade a 7740 with two additional SSDs and it fails to boot.  Any help would be appreciated.  I have tried enough things that I believe this scenario is either not supported, or else I need to change something in the BIOS.  I'm hoping the latter.

 

The 7740 has been running great (2+years) with a boot drive of WD SN750 2TB, and a second drive that is an old repurposed WD Blue SATA SSD (I think it is before they gave them names beyond "Blue", but the part # is WDS200T2B0B).

 

The intended upgrade was to replace the WD Blue SATA with a pair of Crucial P3 4TB drives.

 

I removed the WD Blue, plugged in the pair of P3 drives, and it does not boot.  It goes through the blue boot progress bar, then the spinning dots, then the screen goes black, and a second later it is posting and rebooting.  No blue screen, no hang, just endless boot loop.  The boot loop eventually ends up _trying_ to enter Automatic Repair (or whatever it's called), but that fails in the same way.

 

Before attempting the upgrade I created a recovery disk and tested it by booting it.  With both P3 drives the recovery disk fails to boot as well (same failure: OS loads, then spinning dots, then black screen, then Posting again).

 

I then tested  with a single P3 SSD.  That boots just fine.  With one of them installed in either slot it boots.  With the other P3 installed in either slot it boots.

 

I even built new installation media using the latest MediaCreationTool22H2.exe from Microsoft.  It fails in the same way when both P3's are installed.

So the problem is specifically with the pair of P3 installed.  And the fact that the failure even happens with freshly created installation media makes me think it has nothing to do with my current OS configuration.

 

Is there something that I need to fiddle with in the BIOS to make this work?

[Aaron44126]

If it is set to RAID mode, are you able to switch to AHCI/NVMe mode and see if you can boot install media? This is in BIOS setup in the storage section.

 

If it works, to switch your existing Windows install, you will need to take some steps.

https://www.nbrchive.net/forum.notebookreview.com/threads/precision-7560-7760-owners-thread.836381/page-64.html#post-11112315

[TunaDog]

1 hour ago, Aaron44126 said:

If it is set to RAID mode, are you able to switch to AHCI/NVMe mode and see if you can boot install media? This is in BIOS setup in the storage section.

 

If it works, to switch your existing Windows install, you will need to take some steps.

https://www.nbrchive.net/forum.notebookreview.com/threads/precision-7560-7760-owners-thread.836381/page-64.html#post-11112315

Thanks Aaron, I'll check that when I get home.  I don't know whether it's in RAID or AHCI/NVMe, although if I followed your setup instructions at https://www.nbrchive.net/forum.notebookreview.com/threads/dell-precision-7540-and-7740-owners-thread.830037/page-20#post-10951137 then it's probably in RAID.  

 

The "take some steps" post was at first visually daunting, until I read it.  11 steps, 10 of which are "Boot into safe mode".  Then don't do anything special in safe mode other than reboot as normal.  So presumably merely booting to safe mode should cause the boot process to update/repair itself?