Precision 7530 & Precision 7730 owner's thread

Right—so here's the promised data. I ran two complete discharges of my battery, first with Adobe Lightroom open and minimised, and the second, with nothing running. Only HWiFO was otherwise open for logging, as I couldn't find a way to exert an equal load for both discharges, and it was easier to handle this overnight.

TL;DR: Nearly 12 hours of idle battery life with Adobe Lightroom in the background, versus 6.5 hours with nothing running. The Precision 7530 is definitely capable of low power draw, even with the NVIDIA GPU attached. There is very likely a firmware problem that Dell needs to address, ASAP. Anyone else willing to dig into this is welcome to experiment.

Within the zip linked are two PDFs (and the corresponding Excel spreadsheets) showing the power draw data, plus a regression line for the battery discharge. I also plotted the battery discharge as histograms (filtering outliers), and those are in the zip, too. Even the powercfg battery report is attached, for extra proof. Some spoiler images:

Spoiler: SPOILER: LOW POWER DRAW

LR in background:



Nothing in background, complete idle:

ZIP LINK

 

Alright, that is so interesting, obviously Lightroom is doing something to "fix" the battery discharge caused by the dGPU.
At least you have a workaround now (leave Lightroom minimized all of the time ).

 

I think Adobe should capitalize on this, and re-brand Lightroom as "Battery Doubler!" Joking aside

I revisited my previous battery testing methodology, and discovered that it sucked. Keeping HWInfo64 open, I noticed some pauses and battery jumps, which indicated that the GPU would kick in every five seconds, for no particular reason. Going into nVidia Control Panel, I set Integrated Graphics as the preferred GPU in the base profile, and that zero'ed out the GPU wattage for the duration of my testing session. Then, running only HWInfo64 and saving my virtual machines, I managed to get my power draw down to 17W (no WiFi, 1Gb ethernet only), so long as I didn't breathe on it. That's still a lot better than what I was getting. The DRAM power is a solid 2.5W and didn't seem to budge much from that for 64GB ECC, and I didn't see a clear way to isolate the screen power draw or the HDD power draw.

Running a video full screen (17" 4K), bumped it up to 24W.

Once I stopped the video and started two VMs, usage shot up to 45-60W, and then stabilized at 28W.

Then, playing with the screen brightness, usage would settle at 36W at max brightness or 28W with minimum screen brightness.

Overall, it seems that setting the GPU profile to use the integrated graphics was the #1 thing that helped my power consumption - otherwise, the GPU kicks in all the time at random intervals.

Now, all we need is more people with Lightroom CC and see what happens when they minimize it...

 

Looks like I'm downloading Lightroom.

Is there any reliable way to inform Dell about this? It seems you have a great method to reproduce this issue here, so that should certainly help them with a fix.

*EDIT*

I've downloaded and installed Lightroom Classic CC but I'm not experiencing the same benefit. It pegs the GPU even when minimized, roughly doubling the discharge rate from -17W to -31W.

 

Heh, that's true.

As mentioned earlier, what I think the situation is, is that the firmware doesn't tell the NVIDIA GPU to shut off completely upon start-up, but when Lightroom is minimised, it explicitly tells the GPU to sleep, and hence the power savings.

Might be a DSDT bug.

 

Which version? I'm using v.8.2.

Plus, it's not instantaneous: it takes a while to settle down to around 6 W.

 

8.3.1. I'll give it some time to see if it goes down. If not, I'll try 8.2.

 

@Div033: try to import a photo, set Lightroom to the Develop mode, and then check your power draw.

The power-saving behaviour went away for a while for me, and I was mildly disappointed, and then I realised LR had been in the Library mode (had been importing some photos), when it was previously in the Develop mode. Suddenly power usage dropped again when I changed it back to the Develop mode.

 

Adobe's GPU troubleshooting guide (https://helpx.adobe.com/lightroom-classic/kb/lightroom-gpu-faq.html and updated May 16, 2019) documents when Lightroom benefits from a graphics card, suggesting the possibility that when selected some Lightroom modules might explicitly tell the video card to idle. In Lightroom Classic, for example, Adobe says that only the Library and Develop modules use the GPU. Even when the Develop tab is selected Lightroom could well idle the GPU when you aren't actively editing, which would explain the behavior you're seeing.

 

That makes sense. I'm inclined to believe that Lightroom simply puts the GPU to sleep better than the BIOS does (because I see high power draw in Linux, too—I should try and see if bumblebee works, though).

I really want to escalate this to Dell properly without going through the customer service officer hoops, but I don't know how. I don't really feel like creating a Twitter account just for this.