Dell Pro Max 16/18 Plus (2025 model) pre-release discussion — MB16250, MB18250

[SvenC]

9 minutes ago, capitainealbator said:

Hello, any idea about my question?  😉  🙂 

Yes, it is shown as compatible here dell_docking_compatibility_guide.pdf.external

 

I have the Pro Max 18 Plus with iGPU only and that works flawlessly with my old WD19DC.

[Cadtot]

Yes, the SD25TB5 supports the Dell Pro Max 16 and 18 - has a 300w power supply. It seems to be the only current dock model that does. Compatibility matrix attached.

[capitainealbator]

Thanks @SvenC and @Cadtot 🙂

 

@SvenC: I have a WD19S: do you think it could be ok for a Pro Max Plus 18 with RTX4000 ? 

 

[SvenC]

54 minutes ago, capitainealbator said:

Thanks @SvenC and @Cadtot 🙂

 

@SvenC: I have a WD19S: do you think it could be ok for a Pro Max Plus 18 with RTX4000 ? 

 

The WD19DC has two USB-C plugs and allows up to 210W. I guess the WD19S can only provide 130W, which is not even enough for the iGPU-only PMP18.

 

I would expect it to work if you connect your power adapter and the WD19S - so, periphery from the Dock and power from your power adapter.

[AL123]

5 hours ago, SvenC said:

The WD19DC has two USB-C plugs and allows up to 210W. I guess the WD19S can only provide 130W, which is not even enough for the iGPU-only PMP18.

 

I would expect it to work if you connect your power adapter and the WD19S - so, periphery from the Dock and power from your power adapter.

I’ve only tested with the power supply connected and 1x usb-c connector from wd19dcs , this seems to work ok as a solution to not buy the new thunderbolt 5 dock but still not ideal as you have to remembered to take the 280W usb c power supply with you everywhere. 

[OneSunOne]

I’m trying to decide between the memory options for the Dell Pro Max 18 Plus.

 

From my workload, I’ve found that 96 GB RAM is the sweet spot. That leaves me with two possible upgrade paths:

 

• 128 GB CAMM2
• 96 GB CSoDIMM (2×48 GB)

 

I’m leaning toward the 96 GB CSoDIMM route since it’s much more cost-effective. But I’m wondering: aside from the extra 32 GB capacity, does CAMM2 offer any practical advantages I’d actually notice in real use?

 

Both configurations would be running at DDR5-6400 MT/s. Would there be any benefit in terms of performance, stability, or future-proofing by going CAMM2 instead of CSoDIMM?

[Cadtot]

7 hours ago, AL123 said:

I’ve only tested with the power supply connected and 1x usb-c connector from wd19dcs , this seems to work ok as a solution to not buy the new thunderbolt 5 dock but still not ideal as you have to remembered to take the 280W usb c power supply with you everywhere. 

I run two WD19DCs, one fully powering a Precision 7750 supporting two 4K screens, and the other supporting a Precision 7710.

• The 7710 uses one tail from the WD19DC to support one DP 4K screen, and I use HDMI to support the second 4K screen.

All works fine. :)

[win32asmguy]

@AL123 Have you been able to test the TB5 dock to see if it reduces or eliminates battery drain with the higher 300W power delivery? I can see the CPU pl1 is dynamically set to 58W so combined with the 175W for the GPU seems like it's consistently too much.

[whyshchuck]

I see that biggest factory csodimm configuration is 2x48.
But would it accept 2x64? How do you think?

 

[SvenC]

22 hours ago, whyshchuck said:

I see that biggest factory csodimm configuration is 2x48.
But would it accept 2x64? How do you think?

 

Typically, Dell specs to the max available capacity they can test with and larger sticks which appear later will work as well, same with SSDs.

[win32asmguy]

23 hours ago, whyshchuck said:

I see that biggest factory csodimm configuration is 2x48.
But would it accept 2x64? How do you think?

 

 

If you can find 64GB CSODIMM modules they likely would work. But I think the regular SODIMM 64GB modules available from Crucial currently would not work as the system would not post with a SODIMM installed when I tested.

[MyPC8MyBrain]

@win32asmguy interesting, in theory a standard SODIMM in a system that supports CSODIMM the memory should still run at a lower speed with CKD Disabled, many high-end laptops supporting CSODIMM still ship with standard SODIMM  while the underlying architecture is future proof with CSODIMM support. my guess is this is some intentional nonsense by dell to secure their memory upgrade path monopoly they started with CAMM modules.

[win32asmguy]

18 minutes ago, MyPC8MyBrain said:

@win32asmguy interesting, in theory a standard SODIMM in a system that supports CSODIMM the memory should still run at a lower speed with CKD Disabled, many high-end laptops supporting CSODIMM still ship with standard SODIMM  while the underlying architecture is future proof with CSODIMM support. my guess is this is some intentional nonsense by dell to secure their memory upgrade path monopoly they started with CAMM modules.

 

There is probably a hidden bios option in there somewhere I have not found yet that flags it to require CSODIMM.

 

It can boot aftermarket CSODIMM modules not sourced from Dell. 24GB Hynix modules work well as single rank timings are better and the modules generate less heat than dual rank. The CAMM2 modules have a heatsink built for them so that is what I would choose if I needed more than 2x24GB (highest single rank capacity).

 

My biggest annoyance is still the battery drain under load that is by design. I have a custom charge range set from 70% start to 80% stop, and if the system is under load it is basically always either discharging down by up to 20W per hour or charging back up at 5W (trickle) - 60W (express). Sometimes it decides to express charge the battery even if you are under load so whatever compute task that is running just gets throttled instead. I have even seen the firmware trip some kind of internal throttling protection where the CPU refuses to go over 20W until you unplug and replug the power adapter.

[MyPC8MyBrain]

1 hour ago, win32asmguy said:

My biggest annoyance is still the battery

If you’re plugged into wall power, you can try disconnecting the battery so it’s no longer part of the system’s power management loop.
 

It might be worth experimenting with a clean OS installation while the battery is disconnected, so the system builds its initial power profile more like a desktop. After setup, reconnect the battery so it functions more as a UPS-style backup rather than part of the active power delivery chain.
 

I’ve seen similar behavior before, so this approach might help mitigate the performance throttling effect under heavy load. It’s also possible there’s a low-level BIOS flag (not exposed in the standard interface) that could toggle this behavior natively — Dell loves burying those.

[win32asmguy]

2 hours ago, MyPC8MyBrain said:

If you’re plugged into wall power, you can try disconnecting the battery so it’s no longer part of the system’s power management loop.
 

It might be worth experimenting with a clean OS installation while the battery is disconnected, so the system builds its initial power profile more like a desktop. After setup, reconnect the battery so it functions more as a UPS-style backup rather than part of the active power delivery chain.
 

I’ve seen similar behavior before, so this approach might help mitigate the performance throttling effect under heavy load. It’s also possible there’s a low-level BIOS flag (not exposed in the standard interface) that could toggle this behavior natively — Dell loves burying those.

 

The performance is pretty inconsistent with the battery disconnected. The GPU floats between 60W and 120W while the CPU is around 45W. I guess it does not want to get anywhere near the higher performance limits so a transient spike does not trip the power supply.

 

I tried to ask Dell for a way to disable this feature as I prefer to keep my battery charged at 80% reserved for use when needed. Nor do I want the excessive wear and heat as it continually drains and recharges under the supposed 200W sustained load capability. From what I have heard this is working as designed.

[MyPC8MyBrain]

this is mainly related to advanced battery health management features designed to prolong the battery's lifespan.
 

the "native way" to override this is to use the Primarily AC Use mode in Dell Optimizer or Dell Power Manager, or manually set a Custom charge start/stop limit (e.g., start->50% stop ->100%) to ensure the laptop runs almost exclusively on AC power when plugged in, thus preserving the battery's lifespan.

Use Dell Optimizer or Dell Power Manager
look for a section related to Battery Information or Battery Settings.
You will find options designed to maximize battery lifespan for users who are always plugged in. 
The key settings are:

"Primarily AC Use"
This option is specifically designed for users who primarily operate the computer while plugged into an external power source. It automatically lowers the maximum charge threshold (e.g., to around 80% or a value set by Dell) so the battery stops charging and the system runs on AC power.
 

"Custom"
This gives you the most control. manually set the percentage at which the battery will Start Charging (e.g., 30%) and the percentage at which it will Stop Charging (e.g., 100%).
 

Result: If the battery is below 100% and above 30% and the laptop is plugged in, the system will run entirely on the AC adapter, and the battery will remain at 100% (only acting as an emergency UPS/buffer for peak loads).

or Use the System BIOS/UEFI
set this at the hardware/firmware level or if you do not have the Dell software installed:
Find the Primary Battery Charge Configuration: Look for an option like Primary Battery Charge Configuration or Custom Charge Settings.
Set the Thresholds: You can usually set the Start Charge and Stop Charge percentages directly in the BIOS. Setting the Stop Charge to a lower value (start->30% stop ->100%) will force the system to run on AC power once that level is reached, achieving more or less the behavior you are after.

[Easa]

Guys, perhaps someone here will know, who is the OEM for the 1/2TB Gen5 drives in the PMP18? 

[ebourg]

Dell Pro Max 16 plus reviewed by NotebookCheck:

 

https://www.notebookcheck.net/Dell-Pro-Max-16-Plus-review-One-of-a-kind-mobile-workstation.1132122.0.html

 

The RTX PRO 5000 is capped at 120W under sustained load 😢

[win32asmguy]

10 hours ago, ebourg said:

Dell Pro Max 16 plus reviewed by NotebookCheck:

 

https://www.notebookcheck.net/Dell-Pro-Max-16-Plus-review-One-of-a-kind-mobile-workstation.1132122.0.html

 

The RTX PRO 5000 is capped at 120W under sustained load 😢

 

They may as well cap the 18 Plus at that wattage as well because these drain down the battery above 170W from the CPU+GPU. In theory its designed for 175W GPU + 58W CPU, but the closer it gets to 200W (where thermal throttling starts to occur) drain can be up to 20% per hour. It begins recharging the battery while under load if a charge threshold is set, at a rate of 5W, and reduced CPU+GPU TDP until charging stops again.

 

They also periodically trip some kind of throttling condition which can only be reset by unplugging / replugging the power adapter or a cold boot. Until that happens the CPU is stuck at 15W. I am not sure how extensive Notebookcheck tested their system but it occurs multiple times per hour on my system with the current bios and drivers.

[win32asmguy]

24GB Hynix M-die CSODIMMs boot at 7200 with tREFI at 16k, 1.2v. You can also tune NGU via Intel XTU, so I have it set to 30x up from the default 26x. Sadly D2D is not accessible so it is still at the stock 21x. Supposedly that one is less important based on some tuning I have seen on 285K setups.

 

[1610ftw]

I would like to have a look into the service manual for the Pro Max 18 Plus but it seems a part number is needed for that - does anybody have it?

 

Shame that connectivity is effectively reduced by one port with all current TB5 eGPUs as they only allow up to 140W power delivery and therefore one of the USB-C ports has to be occupied by USB-C power delivery even in cases where only proper CPU performance is desired.

 

Also I take it that there is still no fan control option for these so hopefully the Pro Max 18 Plus fans have enough hysteresis?

[jorgeregula]

Has anyone replaced the stock thermal paste? Any impact of doing that?

I'm considering replacing it with some of the phase change thermal pads (like ptm 7950), does that bring any improvements?

[Easa]

Hey guys! Just unpacked mine. Abnormal behaviour that I have noticed so far:

 

• There were some corrected WHEA errors regarding PCIE Endpoint / Legacy Endpoint. Could be related to the first power-on and the driver updates, as they were logged at that time. Have you noticed these?
• Also there were about 5 ACPI Errors about EC timeout, again, at the same time as the WHEA ones. 

 

I am updating the factory OS to the current day, so all the devices will get their firmwares updated (as well as the BIOS and EC itself) and then i am going with a fresh install. 

PS: I have ordered the system with the SSD door, but the system came with the normal bottom cover. Does anybody here have the PMP18 with the sliding bottom door? The one that you can see on the 3D Visualisation:

[1610ftw]

Sorry to hear that you are missing the door - would that door be for the PCIe 5.0 slot?

I am also surprised about the number of different bottom designs - do you not have the one in the picture you posted above but a third option?

[Aaron44126]

4 hours ago, 1610ftw said:

Also I take it that there is still no fan control option for these so hopefully the Pro Max 18 Plus fans have enough hysteresis?

 

AFAIK, there is still no manual fan control option for Dell systems released on 2021 or later.