Precision 7680 & Precision 7780 Owner's Thread

[rintalahri]

On 3/13/2025 at 1:32 AM, Mambucho said:

 

https://www.parts-people.com/index.php?action=item&id=40784

 

 

 

I need this too, but the balance seems to be 0... :(

[Aaron44126]

24 minutes ago, rintalahri said:

I was also thinking of replacing the camm memories with sodimm memories. Does anyone know which model I should buy or what the differences are?

 

To switch to SODIMM, you need to replace the pressure plate thing in addition to picking up the SODIMM interposer. The interposer uses a different version than the one that they use with the CAMM modules (different thickness). Sorry, I don't know part numbers for anything.

[rintalahri]

22 minutes ago, Aaron44126 said:

 

To switch to SODIMM, you need to replace the pressure plate thing in addition to picking up the SODIMM interposer. The interposer uses a different version than the one that they use with the CAMM modules (different thickness). Sorry, I don't know part numbers for anything.

yes i know, if you mean this: 

 

 

[Aaron44126]

2 minutes ago, rintalahri said:

yes i know, if you mean this:

 

Yep, that's what I'm talking about.

[Mambucho]

12 hours ago, rintalahri said:

I was also thinking of replacing the camm memories with sodimm memories. Does anyone know which model I should buy or what the differences are? LS-L88BP or LS-L88LP

How big sodimms i can put in my precision 7680??

 

 

SODIMM DDR5 Kingston FURY impact 64GB (32*2) 5600MT/s KF556S40IBK2-64 (support XMP 3.0)

[tmr510]

On 11/30/2024 at 5:21 AM, yslalan said:

I repurposed my extra DGFF GPU as an external GPU. It works perfectly.

+1 to the previous post asking where to get one of these.  Any chance you could share a link, I definitely want one too.
Thanks in advance, hoping to repurpose my spare GPU too.

[aze]

hi, new here. wish i found this thread earlier, a lot of good information!

I just got a 7680 with i7 13850hx and rtx 4000 and expected the precision series to be less throttled than my previous xps. shame on me for not doing my due diligence, but here we are.

 

seems to me like we need to turn to hardware to squeeze some more out of these machines. since undervolting, fan control, changing TDP is out of the question, most reasonable approach is trying to solve the cooling issues. 

My total system power have never yet exceeded 155W, so either there is 90W untapped if we can solve the thermals, or the approx 155W is hardcapped and we cant do anything about it. Does anybody know more about this? what are your registered maximum total system power? does anyone know about a hardcap here?

 

in that case i guess we dont have a lot of options? will update on my efforts to resolve the thermals soon!

[aze]

ok, 155 is not at all some limit, playing around with ThrottleStop we can absolutely get more wattage use than that. 

As a first test, i´ll try increasing the flow through that tiny heatsink. The stock fans are low CFM/high static pressure, we could maybe increase the flow through the heatsink with external fans that are sealed to the opening in the bottom of the computer. Ive 3D scanned the bottom part of the laptop, we should be able to make a additional "bottom plate" that seals around the opening with a neoprene sealing, ensuring that we direct all the air through the existing fans and through the heatsink. it might be louder but i dont really mind.

will update!

[TheWizzard1]

@tmr510 OP never shared the link, but I did eventually find these myself.
https://shop559027351.world.taobao.com/?spm=a21bo.29416443.shop_block.dshopinfo.7a7950eesn12v4

[Mambucho]

On 12/8/2023 at 10:04 PM, Sco said:

Does anyone else with a 7780, notice issues with their keyboard backlight? It's more noticeable at an angle rather than head-on. I've had the keyboard replaced twice, same issue.

this was the case on my laptop when I changed the 7680 keyboard. To change it, you need to remove a lot of components. After unscrewing the screws, the keyboard is held on the clips that are on the grid of the front panel, and if, after replacing the keyboard, not all the clips on the grid are connected to the keyboard, this effect will occur. Before you install the motherboard to avoid this, place your palm under the keyboard for support, and from the outside, press on the grid between the keys with a suitable object, across all grid locations. You will hear how the clips connect to the keyboard. If you try to press on the mesh to connect the clips to the keyboard to fix the backlight defect after you have fully assembled the device, it will not work, the keyboard will avoid pressure.

 

P.S

It is also possible that when replacing the keyboard, these clips were broken, and then you need to completely change the front panel, the 7530 grid was removable, unfortunately, the 7680 grid is one with the front panel.

 

 

[Mambucho]

On 3/17/2025 at 5:06 PM, Aaron44126 said:

 

To switch to SODIMM, you need to replace the pressure plate thing in addition to picking up the SODIMM interposer. The interposer uses a different version than the one that they use with the CAMM modules (different thickness). Sorry, I don't know part numbers for anything.

The thin version is necessary for a device that does not have a high-performance enclosure. I have a performance case, SODIMM RAM is set to the thickened version and everything is working. I listened to you and bought the slim version and regretted it, I lost the money.

[Aaron44126]

5 hours ago, Mambucho said:

The thin version is necessary for a device that does not have a high-performance enclosure. I have a performance case, SODIMM RAM is set to the thickened version and everything is working. I listened to you and bought the slim version and regretted it, I lost the money.

 

The purpose of my post was no more than to point out that you need to replace the plate in addition to picking up the SODIMM module. I did not know you were considering picking up a thin chassis system.

[aze]

Repasted from stock to PMT7590 on CPU and GPU die, still waiting for new pads!

After a bit of a deep dive in to the available BIOS modifications ive found some settings that works for me. I dont really have any experience in over or underclocking, so correct me if I´ve misunderstood something!

Seems like other threads discussing potential undervolting paths have died out and i cant find any updated information on possible workarounds for current BIOS version (1.21.0). Disabling "CFG Lock", "Overclocking lock" and "Undervoltage Protection" does not make it possible to set negative voltages. Its possible some additional changes could resolve this, like the XMP profile mentioned earlier in the thread, but I dont have such a RAM. Might buy to try it out but right now its not highest priority.

I turned to the AC loadline modifications which in effect reduces the voltage to CPU by underestimating the voltage drop between power rail and CPU, leading to the CPU requesting a lower voltage. Default AC Loadline (Hardware default) values of my 7680 was 1.7mOhm according to HWiNFO. I lowered this in steps down to 0.8 mOhm. At 120A current through the CPU voltage regulator i think that would be equivalent to approximately -75mV undervolting. Difference is that it scales with the amperage so it does not give lower idle temperatures. I ended up turning it back up to 1.2mOhm, kinda settling with some middle ground alternative. 

Even if undervolting would work great, thermals are still whats in the way between utilizing the full hardware capabilities. I took apart the heatsink and estimated the surface area to approximately 600cm2. Its made from anodized aluminum and if I didnt miscalculate completely the maximum power we could possibly dissipate from it under ideal flow conditions is around 190W. 

The 2 fans im my machine are Sunon MG75090V1-C310-S9A. Its a Dell specific variation of these:

https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/2409/4555HQ-MG75090V1-1C090-S9A(D07026160F-00)-0 05092022.pdf

They are low flow/high static pressure radial fans, since the heatsink gives high resistance due to compactness, this is probably a suitable choice since the low flow improves the acoustics. I dont have datasheet for the Dell specific C310 variant, but it says 7.7CFM on the fan. Lets say their custom model can give 7.7CFM at 11 mmH2O, compared to the datasheet variant that gives 5 CFM at 11 mmH2O. We dont know the exact resistance to flow over the heatsink, but it could be simulated using a 3D-model, which is feasable but unclear what we´ll gain from it other than its a fun excersice.  I think its enough to conclude that we need better hardware for cooling.

My initial idea using an external fan that can at minimum supply the required 7.7CFM at a static pressure of lets say 5 mmH2O. If we could seal the outlet of that fan to the inlet of the stock fans, the pressure difference over the stock fan would decrease and we could get the stock fan to "climb" on its PQ-curve (pressure vs flow), resulting in higher flow.
The problem is that the stock fan is limited not by its inability to overcome the pressure, but the fan speed, which is under EC control. I wont bother diving in to that rabbit hole since I dont know enough about it. The stock fan speed will limit the flow over the heatsink if we don unplug them and use high pressure/high flow fans, and that will be way to bulky and loud for anything practical.

I dont know enough about heat pipes, but I think we can assume they are not the bottleneck. Most probable its the heatsink. We cant just change the heatsink, I think best approach is to make a complete custom heatsink assembly. I wouldnt be able to make it better than the existing heatsink assembly with the same space constraints, but since I dont really care about manufacturability/price/weight like the engineers at Dell needs to, I´ll try expanding the space.

Current idea is building a new bottom plate but adding additional thickness to accomodate for a bulkier heatsink assembly. I have designed the new bottom plate but have not made a physical prototype. I´ll 3D-print it and ensure its sits in place. If it works i´ll try to put something together with air cooling. Maybe it´ll be too bulky and water-cooling is the way to go. We´ll see

[Mambucho]

2 hours ago, aze said:

Repasted from stock to PMT7590 on CPU and GPU die, still waiting for new pads!

After a bit of a deep dive in to the available BIOS modifications ive found some settings that works for me. I dont really have any experience in over or underclocking, so correct me if I´ve misunderstood something!

Seems like other threads discussing potential undervolting paths have died out and i cant find any updated information on possible workarounds for current BIOS version (1.21.0). Disabling "CFG Lock", "Overclocking lock" and "Undervoltage Protection" does not make it possible to set negative voltages. Its possible some additional changes could resolve this, like the XMP profile mentioned earlier in the thread, but I dont have such a RAM. Might buy to try it out but right now its not highest priority.

I turned to the AC loadline modifications which in effect reduces the voltage to CPU by underestimating the voltage drop between power rail and CPU, leading to the CPU requesting a lower voltage. Default AC Loadline (Hardware default) values of my 7680 was 1.7mOhm according to HWiNFO. I lowered this in steps down to 0.8 mOhm. At 120A current through the CPU voltage regulator i think that would be equivalent to approximately -75mV undervolting. Difference is that it scales with the amperage so it does not give lower idle temperatures. I ended up turning it back up to 1.2mOhm, kinda settling with some middle ground alternative. 

Even if undervolting would work great, thermals are still whats in the way between utilizing the full hardware capabilities. I took apart the heatsink and estimated the surface area to approximately 600cm2. Its made from anodized aluminum and if I didnt miscalculate completely the maximum power we could possibly dissipate from it under ideal flow conditions is around 190W. 

The 2 fans im my machine are Sunon MG75090V1-C310-S9A. Its a Dell specific variation of these:

https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/2409/4555HQ-MG75090V1-1C090-S9A(D07026160F-00)-0 05092022.pdf

They are low flow/high static pressure radial fans, since the heatsink gives high resistance due to compactness, this is probably a suitable choice since the low flow improves the acoustics. I dont have datasheet for the Dell specific C310 variant, but it says 7.7CFM on the fan. Lets say their custom model can give 7.7CFM at 11 mmH2O, compared to the datasheet variant that gives 5 CFM at 11 mmH2O. We dont know the exact resistance to flow over the heatsink, but it could be simulated using a 3D-model, which is feasable but unclear what we´ll gain from it other than its a fun excersice.  I think its enough to conclude that we need better hardware for cooling.

My initial idea using an external fan that can at minimum supply the required 7.7CFM at a static pressure of lets say 5 mmH2O. If we could seal the outlet of that fan to the inlet of the stock fans, the pressure difference over the stock fan would decrease and we could get the stock fan to "climb" on its PQ-curve (pressure vs flow), resulting in higher flow.
The problem is that the stock fan is limited not by its inability to overcome the pressure, but the fan speed, which is under EC control. I wont bother diving in to that rabbit hole since I dont know enough about it. The stock fan speed will limit the flow over the heatsink if we don unplug them and use high pressure/high flow fans, and that will be way to bulky and loud for anything practical.

I dont know enough about heat pipes, but I think we can assume they are not the bottleneck. Most probable its the heatsink. We cant just change the heatsink, I think best approach is to make a complete custom heatsink assembly. I wouldnt be able to make it better than the existing heatsink assembly with the same space constraints, but since I dont really care about manufacturability/price/weight like the engineers at Dell needs to, I´ll try expanding the space.

Current idea is building a new bottom plate but adding additional thickness to accomodate for a bulkier heatsink assembly. I have designed the new bottom plate but have not made a physical prototype. I´ll 3D-print it and ensure its sits in place. If it works i´ll try to put something together with air cooling. Maybe it´ll be too bulky and water-cooling is the way to go. We´ll see

I bought Kingston FURY Impact 64GB (32*2) 5600MT/s SODIMM DDR5 memory (model KF556S40IBK2-64, supports XMP 3.0), installed it, and got a frequency drop to 5200MT/s on my device. It automatically selected the profile that is preset inside the memory from the factory; you won't be able to switch to 5600 as there is no control over these profiles in the BIOS. The CPU-Z program cannot detect the XMP profile. Forget about the idea of installing RAM with XMP support, you will not get what you want.

[aze]

On 5/24/2025 at 2:09 AM, Mambucho said:

I bought Kingston FURY Impact 64GB (32*2) 5600MT/s SODIMM DDR5 memory (model KF556S40IBK2-64, supports XMP 3.0), installed it, and got a frequency drop to 5200MT/s on my device. It automatically selected the profile that is preset inside the memory from the factory; you won't be able to switch to 5600 as there is no control over these profiles in the BIOS. The CPU-Z program cannot detect the XMP profile. Forget about the idea of installing RAM with XMP support, you will not get what you want.

Thanks the info! I have seen XMP profiles mentioned in hidden BIOS menu shown via smokeless umaf, so it might be possible there! Might be risky though