Dell Latitude 5491 and 5591

BIOS 1.3.8 is out, seems to be a little quieter -- I think it's slowing the fan back down after it cools a little more quickly. No improvement in the throttling. although the undervolting and limitation of the turbo wattage has left things tolerable.

Also, for anyone running Linux with a (especially if you run your own kernel configuration) the OpenFirmware drive on 4.18 (which isn't necessary for normal PCs of present generation) is enabled by default on 4.18, and causes a crash on every Dell machine I've tried it on (5470, 5491, 9560, and an Optiplex 9020.) Disabling "CONFIG_OF" and recompiling fixes this. Took forever to track dow

Other than a less-than stellar LCD panel (and I'm a bit spoiled with my personal one being the 9560 IGZO panel) a couple months in I'm still very pleased with this machine.

 

Did anybody try the i5-8400H version?
Considering it as a portable replacement for my current work PC i7-6700 non-K, 32GB (doing primarily JVM/bigdata coding/ops under Linux). The thing is that it's available at my local store and has a much more appealing price, about 450$ less compared to i7-8850H version.
I know that both CPUs are rated for 35-45 TDP, but should it be expected due to fewer cores that 8400H will be less susceptible to thermal issues?

 

While the clock speed boost is nice over Skylake/Kaby Lake, it wouldn't have been a big enough improvement over my existing machines to be worth upgrading. If you don't have a 32GB Skylake or newer quad core laptop, this could be very attractive. The one question I'd ask is whether the 5480 is still available where you are -- for the US market, there are still a few i7-7820hq models on Outlet (not clear if they're going to get more) that are going for very low prices, and I'd imagine any new ones left in the retail channel would go for a song. All other things being equal, I'd take the 5491 i5, but I don't think I'd pay much of a premium for it over an i7 5480.

I'd expect the thermal behavior on to be at least modestly better, although if they're using the same 6-core die with 2 cores disabled, it may not be as much better as you'd expect.

 

Thank you for 5480 suggestion, @mr_handy! Few online retailers still claim they are available for sale, but it's questionable. The price is a bit higher though: 5480 latitude with i7-7820HQ goes for 1520$, while 5491 with 8400h is around 1420$. Given this price difference and the thunderbolt on 5491 (implies dGPU), probably I'll just get this machine. The performance improvement isn't so important for me at the moment, as I'm quite happy with my current i7-6700 work desktop. So roughly equal performance in a portable chassis is all I need.

 

Definitely no reason (or at least very little reason) to get the older one if it's more expensive -- I'm just surprised that it is more expensive in retail channels (for direct ordering, Dell often charges more for outgoing Latitudes to take advantage of companies that would rather overpay than take the time to roll out a new image/qualify a new model.)

https://ark.intel.com/compare/97496,134877

For a lot of uses, the higher turbo frequency of the i5-8400h will make it actually run things faster than the nominally higher base frequency on the i7-7820hq -- reflected in the passmark averages, for example.

In practice for most things, the difference won't be noticeable either way, and both will still be both in roughly the same performance ballpark as your desktop (for some things, the 6th generation desktop processor may still be a little faster, for others, the 8th generation mobile, but I doubt it will be noticeable unless you're benchmarking or running really big long-running jobs where the desktop would shine.)

 

@mr_handy what can you say about the value of Thunderbolt in the dGPU version? Any reason to go for it? Say for building a workspace with 2 external FHD monitors, keyboard/mouse will it be more convenient to use a thunderbolt dock?

 

Dell requires something more than their 90W adapter for the dGPU/TB3 model (they use their 130W charger).

You may not be able to get a single cable hub/"dock" solution in that case, since TB3 power limits are 100W.

 

I am looking into buying the 5591 laptop [i5-8400H processor , 512 GB SSD, 16 GB RAM] . I would have no real need for dedicated graphics----My question is if I purchase the 5591 configured with only integrated graphics, would the 5591 chassis still contain the 2 heat pipes as indicated in the Bernie Pechlaner review of Aug. 6 ? (I am hoping to run the laptop as cool as possible)

I would really appreciate any expertise or advice on this.

Many thanks!

 

I've got the iGPU one, and the WD15 dock (displayport over USB-C) will only run a 4K monitor at 30hz, or at my prior job, 2x 2560x1440 would not run (off an M5510) -- I had to use one HDMI cable and the dock. The WD15 powers the iGPU 5491 just fine, with a 180W supply.

In theory, the TB16 dock should be better (the first gen TB15 dock didn't work well even for our Windows users) in terms of the resolutions it can do. Not sure about the 5491/5591 or the WD16, but Dell somehow pushes a lot of power through USB-C or Thunderbolt -- the TB15 w/ 240W and the WD15 with 180W supplies both would power the 130W M5510 or XPS15-9560 just fine, and I'd have thought that would be true for the 5491/5591 as well.

 

Anyone here using 5591 with 8850h? The cooling system seems really bad, and I'm wondering about Temps and GHz-sustainability after undervolting. Anyone tried it?