Dell Precision M3800 Owner's Review

The rule is that if you do anything that significantly changes the PPI of the display designated as primary while you have a logged-in session, then you'll need to log off and log back in for Windows to adjust your UI properly. Events that would trigger a PPI change include:

- Disconnecting an external display that was used as primary if the new primary display has a significantly different PPI -- since in your case, the new primary would be the built-in panel, this would apply.

- Connecting an external display that was used as primary last time it was available and that has a significantly different PPI than whatever display was primary immediately prior to you connecting said display -- again, since you would be switching from built-in FHD to external FHD, this would be the case.

- Going into your settings and designating a new primary display that has a significantly different PPI than the one you were using before.

- Going into your settings and significantly changing the resolution of your primary display.

Going into your settings and changing your scaling preference would also require a logoff/logon, but that's true of Win7 as well. However, note that in some cases you can connect/disconnect external displays without causing any problems. For example, if were using two U2415s (and not the built-in panel) you could change which one was primary or even disconnect/connect one of them without needing to do the logoff/logon dance because the PPI of the primary display isn't changing. Likewise, if you had the built-in QHD+ panel and an external 24" 4K panel, you could connect and disconnect the external display at will since the PPI is close enough between the two; Windows would default to driving either of those on its own at 200% scaling, so it has no problem adjusting perfectly on the fly.


But in your case of the built-in FHD panel and an external U2415 or U2515H, let's examine a few scenarios:

- While logged in, you disconnect an external display that was being used as primary, or connect one that Windows used as primary when it was last available, or just go into your settings and change the primary designation to a new display -- in any of those cases, a logoff/logon will be necessary.

- You log in, lock your workstation (or put it to sleep or hibernate), and then unlock/resume it without having changed your display configuration -- no need to do anything special. Note that it's perfectly fine to disconnect the external display while the system is asleep/hibernated, so long as you return to the original display configuration when you want to start using the system again.

- You log in, lock your workstation (or put it to sleep or hibernate), then connect/disconnect a primary display, and then unlock/resume the system with this different display configuration -- logoff/logon will be necessary.

- You do a full shutdown (or restart), which closes your user session, then connect/disconnect a primary display while at the startup logon screen but before actually logging in -- no need to do anything special.

- While logged in, you disconnect your primary display, do NOT log out, use your system for a while (in a suboptimal UI setup), and then reattach your external display -- no need to do anything special. The reason here is that since you didn't log out in that intermediate phase, Windows never switched out of the mode it used when your external display was attached, so when you reattach it, it's still in the proper mode, so you can continue as normal. This could be handy if for example you only need to use your system away from your external display for a little while and the inconvenience of a suboptimal UI for a while is less than the inconvenience of doing the logout/login dance twice (since if you HAD logged out and back in during that intermediate phase, you'd have to do so again when reattaching the external display.)

Does that make sense?

 

OK I think I have got it…but just to check as there are some interesting scenarios you raise I hadn’t thought of:

Re: your 2nd point: So once I connect the external primary display in the morning, as long as I do not physically disconnect the M3800 from the monitor during the day, if I lock the M3800 (or put it to sleep or hibernate) there will no need to logoff/logon during the day when I Resume using the M3800 power button?

Re: your 4th point: so if I Shutdown M3800 at the end of the day, as long as I reconnect the external display the next morning before logging on for the first time, there will no need to do the logoff/logon procedure? That’s a bonus scenario I had not realized.

Re: your 5th point: so if I disconnect the M3800 from the external display during the day and do not logout, I can use the M3800 albeit with a suboptimal UI for a while, and if I reconnect to the external display there will no need to do the logoff/logon procedure? That’s another bonus scenario I had not realized.

Many thanks.

 

Your understanding of all of those scenarios is correct. When you first log in to open your user session, Windows examines the PPI of the current primary display and uses that (plus any scaling preference you may have previously changed from the Windows default) to determine the "baseline" scale factor for the session. At that point, the UI is rendered optimally for the primary display, and any other displays with significantly different PPIs get GPU-scaled versions of content that was rendered internally at the baseline scale factor. But the key fact is that that baseline scale factor is persistent for your entire user session -- even if the primary display's PPI changes, including due to being disconnected (in which case all active displays will become GPU-scaled). So make any display changes you want before you actually log in to start your session, and then whenever you're using whatever display configuration was active when you first started that session, you will always have an optimal UI on your primary display, regardless of any mid-session activity that may have occurred, such as lock/sleep/hibernate periods or even connecting/disconnecting a display. If on the other hand you really do want Windows to optimize its UI for a new display configuration and new primary display, you have to log out and log back in while the new configuration is active, which will cause Windows to choose a new baseline scale factor optimal for that configuration. Enjoy!

 

I know that some have had success with driving an external 4k display with the older non-4k version, but what about with the new version that has an integrated 4k screen. Are there any issues?

Also, any thoughts about the possibily of having a stable setup using 2 external 4k displays, one driven at 60hz via DP and one driven at 30hz (secondary screen so a bit of lag would be more acceptable) via hdmi or even coming off a usb3.0 dock? The Intel specs for 4600 graphics actually indicate the potential to drive 3 displays at 4k resolution, so them limiting factor here seems to be connectivity throughput.

 

Looking only at the GPU side of this question, the Intel 4600 GPU can indeed drive 3 displays, and all of them can be 4K displays @ 60 Hz as long as all of them are SST. Any MST displays count as two displays. I can't see why the built-in panel being 4K rather than QHD+ would be a factor. However, as you point out, the limiting factor to triple 4K @ 60 Hz here is the connectivity on the system itself. Given that we've already established that 4K @ 60 Hz (both SST and MST) works through DP and that 4K @ 30 Hz works over HDMI, I don't see anything to suggest that simultaneously driving the built-in 4K panel and two external 4K SST displays (one @ 60 Hz and one @ 30 Hz) wouldn't be possible, but I don't have the hardware to test this.

 

Very much appreciate your insight. I have two m3800s on the way along with two p2715q displays, so I'll "borrow" both displays for a test and report back. If it works, well, I may just keep both displays and leave my employee to just be elated over the weight difference between the new laptop and her current m6600...and if it doesn't, one 27inch 4k display will more than match my two 24inch HD sets...

 

Thanks for the review. I am actually surprised Dell is tweaking the system, I was expecting a vanilla Ubuntu installation (which should work reasonably well these days).

On the other hand, certain things can be definitely improved over a default installation:

• Nvidia drivers and bumblebee (as the only option as of today that puts the dedicated card to sleep when not in use)
• Power usage tweaks (battery life is not good with the default options, there are some tweaks that can be made)
• Synaptics options (such as two-finger scrolling) are not enabled by default
• Firefox's default dpi

Anyway, nice to see Dell trying to enhance the out of the box experience. If you find out anything else about these tweaks, please share them here and/or in the wiki.

 

It seems that performances of new Dell Wireless AC 1560 adapter (based on Broadcom chip like Macbook) are much better than Intel AC 7260 adapter.
This is review of new XPS 13 with Dell AC1560 compared with XPS 15 with AC 7260, AC 1560 transfer speed is double than Intel AC 7260:

http://www.anandtech.com/show/8983/dell-xps-13-review/3





I wonder if it's possible to buy Dell AC 1560 adapter is some way, also could be interesting to know how is even the new Intel AC 7265.

 

It probably is possible to get the Intel 7265 or DW 1560, if not directly through Dell Spare Parts then certainly from third-party sellers at some point in the future. The new M3800 is shipping with the DW 1560 chip, so I can't imagine that it wouldn't be compatible. However, I wouldn't conclude from this chart that you can expect a 2x increase in throughput, though. AnandTech doesn't provide any details of their WiFi testing methodology, so we don't know what conditions are required to hit these numbers, and more importantly, the comparison is between two different systems. Chassis and antenna design differences between system models can also contribute to WiFi differences even with identical WiFi chipsets -- for example, back in the days of plastic Macbooks, their WiFi routinely outperformed their aluminum MBP counterparts with identical chipsets because radio signals travel better through plastic than metal. Even here, the Intel 7265 is posting far better numbers than the 7260 in the XPS 15 they tested, and I'm skeptical that such a dramatic improvement is solely due to a minor chipset revision from Intel rather than differences in system designs, variations in testing conditions, or even a revision to their testing methodology since the XPS 15 was reviewed.

But I for one am happy that my two Intel 7260-equipped systems can consistently pull my full 200 Mbps of downstream Internet bandwidth, even though I'm using an N router, namely the amazing ASUS RT-N66U. And since I don't do any heavy streaming between local devices, or even routinely max out my Internet connection, I don't really need more performance myself.

 

The new M3800 in the tech specs of Dell's site says:
Connectivity

• Wired: USB3.0 to Ethernet adapter included
  Wireless LAN: Intel® Dual Band Wireless-AC 7260 Plus Bluetooth 4.0
  Dell Wireless 1560 2X2 802.11ac + Bluetooth 4.0

Dell Wireless 1560?