Dell Latitude 5491 and 5591

I wonder, since the VRMs are external and Dell seems to be going Apple's way of thermal throttling, how much influence does the package power limit or TDP have? On some laptops, VRM overheat will force downclocking, and It seems if VRM throttling isn't the issue, we get CPU temperature throttling in its place.

 

Hello,

I've got new Latitude 5491 with 8850H and MX 130

It was repasted by the reseller and got Windows 10 Pro.

Please, can you tell what free software I can run to measure its performance and detect unstable behavior under load?

 

Furmark is a good choice if you're just trying to see how hot it gets or if it's unstable. You'll need to run something else with it to detect throttling; Intel CPU Gadget is probably the simplest option.

(On linux, "for a in `seq 1 24'; dd if=/dev/urandom of=/dev/null & done` is a good way to generate a big multithreaded load (2 threads per vcore, and then you can use i7z to check the CPU speeds and/or throttling)

In terms of "measuring its performance," generic synthetic benchmarks are pretty meaningless; you need to find a benchmark that tests what you're actually going to do with it.

 

Inside and keyboard (and boring underside and inside bottom) photos sorry for the delay been busy!

 

Ah, now I see why the dGPU versions require M.2 SSD. The southbridge goes where your WiFi card currently is.

 

Overall, I'm pretty happy with the port layout and in principle I like the back exhaust better than the side exhaust on my 5470, but even with undervolting and a slight wattage reduction, I can't get rid of throttling entirely. Given the alternatives available to me in a work machine, I'm happy with it (and my management chain is happy that it's cheaper than the M5520 they'd otherwise have ordered for me), but I'm definitely not buying a second one for personal use to replace my current XPS and will be waiting for the 9th gen CPUs and will see what the options are then.

It's a pity so many of the full power 15" PCs have gone to numeric keypads, and that the ergonomics on the XPS/M55x0 are so terrible. I may Alienware on my next machine, super-heavy though they are.

 

I thought that CPU is at the end of heat pipe, and green square in the middle of pipe is dGPU. But above picture is from iGPU configuration. Can you please tell what is what really?

My quick test with HWiNFO and Prime95 showed:
At test start, all cores at 3.4GHz, almost 100W power, thermal throttling is reported around 98C
After a minute it stabilizes at 2.4GHz on all cores, temps at 90C, power 60-70W, no thermal throttling.

(I can report some specific metrics for comparision if there is another Windows user that knows what is important in HWiNFO)

I did not take it to work yet, but for occasional compilation and running tests, it seems nice to have such speed boost for few seconds.

Maximum fan is loud but I do not consider its pitch as annoying. It spins spontaneously after CPU enters 4GHz boost for no reason. I did not yet update BIOS to newest.

 

A surprising amount of parallel thought here! I agree with basically all of what you have said. I'm facing the same trouble replacing my E5450. In principle, I come from the Alienware M11x R2 (first laptop I ever purchased), which biases my view in favor of small powerhouses. I fear the next gen and 10nm CPUs will not be our saviors in this. Power savings past 20-22nm have not scaled as quickly as the area savings.

Southbridge. The H series chips still have a separate southbridge (PCH in Intel-speak). The dGPU versions probably move the southbridge to another location and the dGPU takes the prime spot under the heatpipe. I believe the 15" version puts the southbridge roughly where the wifi card currently is (referencing the picture above).

Technically speaking, all current Intel Core CPUs (not Atom) have separate southbridges. The U and Y series chips simply place it on-package. Desktops ("S series" in Intel's naming scheme) and higher power laptops (H series) use separate packages for the CPU and southbridge.

 

I *love* having the numpad on the side - don't think I'll ever go back to a machine without one. I use it most for entering dimensions (#'s) in CAD, or IPs when doing IT work.

 

It's a pity no manufacturer has figured out how to do one model which was configurable with and without.

I find having the keyboard off-center incredibly distracting, but it seems like the market favors them except for conspicuously-copying-Apple models like the XPS15/M55x0.