It is important because the original Core-M was specifically developed for fanless tablets where silent operation, a thin profile, and low weight mattered. These chips had to dissipate as little heat as possible, and that meant running them at a very low default clock speed.

The Core-M chips in the original tablets were rated at just 4.5 watt Thermal Design Power. They could run at much higher turbo speeds, but only for a brief time. This made them suitable for low overall workloads, with just a bit of high load mixed in.

It's an interesting idea, but in our experience, those Core-M chips were quite temperamental (as are, to a somewhat lesser extent, their successors) and you could never quite predict whether they would actually spool up to turbo speeds, or sit a particular assignment out. Not exactly what one needed out there in the field.

Dell apparently came to the same conclusion. Yes, tablets must be as thin and light as possible, but not at the expense of consistent, reliable performance. As a result, with the 2nd generation of the tablet, Dell switched from 4.5 watt Core-M processor to "full" ultra-low voltage Core processors with a Thermal Design Power of 15 watts. And now, with the 7220, all processors are powerful 8th generation Core chips.

But doesn't that mean much higher battery draw? Not necessarily. Intel has made significant progress in power conservation, and late generation mobile Core processors can have amazingly small power draws. The table below shows the three processors available for the Dell Latitude 7220 Rugged Extreme Tablet, with their major specs (see the full table here):

CPU Options	Intel	Intel	Intel
Intel	Core i7-8665U	Core i5-8365U	Core i3-8145U
Codename	Whiskey Lake	Whiskey Lake	Whiskey Lake
Cores/Threads	4/8	4/8	2/4
Lithography	14mn	14mn	14mn
Base Clock Speed	1.90 GHz	1.60 GHz	2.10 GHz
Turbo Speed	4.80 GHz	4.10 GHz	3.90 GHz
Thermal Design Power (TDP)	15 watts	15 watts	15 watts
Smart Cache	8MB	6MB	4MB
Integrated graphics	Intel UHD Graphics 620	Intel UHD Graphics 620	Intel UHD Graphics 620
Graphics base speed	300 MHz	300 MHz	300 MHz
Graphics max speed	1.15 GHz	1.10 GHz	1.00 GHz
Intel vPro	Yes	Yes	No
Intel SIPP	Yes	Yes	Unknown
Intel Trusted Execution	Yes	Yes	No
CPU relative cost	1.46	1.06	1.00

At the low end is the Core i3-8145U. This chip is the only dual-core model of the trio. That's not inherently bad; no ultra-low voltage Intel Core chip of the first seven generations ever had more than two cores. And the since it's a dual-core design, Intel allowed it — likely for power consumption reasons — a higher default clock speed than the quad-core options. As a result, the i3-8145U will probably handle light loads and routine jobs just as well as the two higher-end chips.

The Core i5-8365U and Core i7-8665U both have four cores and eight threads, with the i7 chip also having more Intel Smart Cache (8mb instead of 6mb) and slightly quicker maximum graphics. Other than that and overall slightly higher performance of the i7-8665U, there isn't much of a difference between the two.

Customers will likely ask themselves: Are four cores really twice as good as two? The answer is, as in almost all things, "it depends." It depends on how much of a software application can be broken down into steps that can be run in parallel. If it's a lot, then a quad-core design will likely be considerably faster than a dual-core CPU.

But doesn't that also mean considerably higher power draw? Again, that depends. If a quad-core design runs at the same default clock speed as a dual-core system with the same architecture, then, yes, it'd draw much more power. And that's why, for now, Intel lowered the default clock speed of the quad-core chips by quite a bit. And, thanks to optimization in the 8th generation dye, managed to increase maximum turbo speed.

The result is that, theoretically, the quad-core chips Dell offers for this tablet can match or exceed dual-core performance when just idling along doing light loads and drawing not much power. But they have much higher peak performance.

In order to get a sense of the Dell Latitude 7220 Rugged Extreme Tablet's performance, we installed Passmark Software's PerformanceTest 6.1 and 9.0 that run many dozens of tests covering CPU, 2D graphics, 3D graphics, memory, and disk and then compute scores for each category and an overall PassMark score. We also ran our older benchmark suite, CrystalMark, which concentrates on single core performance. For comparison, we added the results of Dell's original Latitude 12 Rugged Tablet, the second gen Latitude 12 Rugged Tablet Extreme, and three tablet competitors that we had also recently tested in the RuggedPCReview benchmark lab.

Another challenge makers of rugged Windows tablets face is that they have to build this complex package with all those standard PC ports so that dust and water won't get inside. And they have to design the package so things don't break or come loose when the device is dropped and rattled around. How did Dell go about making it all possible?

By expanding on existing technology. When Dell initially designed their rugged tablet platform, they had already launched their existing Latitude 12 Rugged Extreme convertible notebook (see our full review), and that machine serves as the conceptual and general foundation for Dell's rugged tablets.

In essence, Dell condensed the guts of their convertible into a pure tablet form factor, retaining the same 11.6-inch display size and much of the functionality. The pure tablet form factor enabled them to reduce weight by 40% compared to the convertible, and, of course, they updating underlying technologies in the process.

That's not to say that the tablet and the convertible used the same internal layout. Tablets and convertibles are inherently different, with convertibles being two-box designs and tablets all-in-ones.

Unlike most mobile Windows systems, the Latitude 7220 Rugged Extreme Tablet doesn't have any removable covers on its backside to provide access to RAM memory and internal expansion slots. So if you want to replace memory or one of the PCIe modules, or if maintenance becomes necessary, you have to open up the tablet.

That's fairly easy. Undo a couple of dozen small Philips screws and the halves come apart. There are, however, three ribbon cables with fragile connectors between the halves. These connectors have to be carefully unplugged.

The seal between the back and the front part of the housing — both made of impact-resistant, flame-retardant, fiber-reinforced PC-GF50(40) polycarbonate — is a hard plastic lip on the backside that presses onto a thin black (in designs like that, we like to see the seal in a contrasting color; that makes it much easier to examine it for damage) rubber o-ring seal sitting in a channel on the front side. The o-ring seal is long and complex but seems replaceable. What's interesting here is that the seal doesn't just go along the perimeter of the tablet. Instead, it weaves in and out, protecting the electronics inside, but leaving anything I/O-related outside.

That's because it is not easy to properly seal standard PC ports and connectors. In most rugged devices those ports are not actually sealed to the inside. Instead, rubber plugs and hinged doors provide the protection. If one of them isn't closed properly, liquids can enter the inside of such devices. With Dell's design, it can't.

In the Dell tablet there are protective plugs also, but if one of them is damaged or not closed properly, liquid may enter the I/O compartment they protect but it can't get into the interior of the tablet. Doing it this way is more complex, but potential damage is limited to an I/O module and not the entire tablet. And I say "potential" damage, because Dell actually applies what they call HZO liquid protection and describe as a "nanotechnology solution that inoculates electronic components from damage and failure."

An additional advantage of separating I/O modules from the motherboard is that this makes it much easier to upgrade and/or customize I/O. No need to redesign the motherboard.

Even though the internal layout of the Latitude 7220 Rugged Extreme Tablet is complex, components such as WiFi (ours had an Intel Model AX200NGW half-card), PCIe NVMe SSD mass storage, GPS (NEO-M8N), and other wireless modules, as well as the various antenna blocks, are easily accessible once the tablet has been opened.

The modularity, of course, is in Dell's DNA, the result of decades of offering an almost infinite number of permutations of options available right on Dell's website. So almost any feature for which there might be alternatives — or of which a customer might want more or less of — is not on the motherboard but designed as modules.

One thing that's immediately obvious is that the Latitude 7220 Rugged Extreme Tablet packs industrial-grade thermal management. That includes a fairly sizable fan with a heavy metal enclosure that, of course, is sealed towards the interior of the device. Two copper pipes conduct heat away from the processor, ancillary electronics, and also the PCIe-based SSD.

Interestingly, the initial Dell Rugged Tablet only had a tiny and nearly invisible fan and no heat pipes. Why the change to beefier thermal management? That's because the original tablet's processor had a TDP rating of just 4.5 watt whereas the one in this tablet is a 15 watt design.

But 15 watts is still considered ultra-low voltage by Intel, and aren't all ultra-low voltage processors supposed to be able to operate without fans in Windows tablets?

Initially, yes, under certain circumstances. That's because early Intel ultra-low voltage processor did not have a "turbo" mode that allows CPUs to briefly run much quicker than their nominal clock frequency, as long as temperatures don't exceed certain levels.

Turbo mode is great, but it can turn into a problem in rugged machines. When a machine gets too hot out there in the desert and there is no active cooling, performance will drop, and can drop to unacceptable levels. That's why Dell chose to use a powerful fan in the Latitude 7220 Rugged Extreme Tablet. This way, performance will not drop, no matter what.

The pictures above show the Dell Rugged Extreme Tablet's thermal engineering, taken with our FLIR One Pro infrared camera during a performance test benchmark run.

The bright yellow areas are the hottest, and that is where the heat is conducted away from electronics via the system's copper pipes. On the left side of the picture you can see the fan and its cooling effect. As a result, even during a sustained high performance load we never saw more than mid 90F degree temperatures.

Overall, the interior of the Dell Latitude 7220 Rugged Extreme Tablet is a complex, sophisticated affair that very much shows Dell's experience in mobile computing technology. Components and modules are clearly marked and have their own 2D scan code. Wires that go from modules to their respective antennae located around the perimeter of the tablet for best reception are guided and held in place with little loops and guides.

But, regardless of size or sharpness, providing the right display for a system that's being used outdoors is much more difficult than for one that's mostly used indoors in an office or at home. That's because we now have incredibly sharp, photorealistic-grade displays for indoor use, displays that one can't imagine getting much better. But outdoors is a totally different story.

That's because a) it's much brighter outdoors, with even the brightest display not being a match for sunlight, and b) because there are all sorts of reflections that can quickly make a display unreadable.

With regard to LCD outdoor viewability, Dell has been a pioneer. As far back as 2007, Dell had laptop displays that had their screen cover optically bonded to the LCD, thus eliminating the reflections from the LCD surface, eliminating the need to AR-coat the bottom of the screen cover, and eliminating the air gap.

The methods Dell applied reduced overall reflectivity and resulted in a very good effective contrast ratio. At the time, we termed it "definitely readable in sunlight." That was rare back then.

Time doesn't stand still though, and good outdoor-viewable displays are now available from all of the major rugged laptop vendors. Some are offering very high screen brightness of up to 1,500 nits, and optical treatments are continually refined. In the past, Dell favored advanced optical treatments that concentrated on reducing reflected light as opposed to using battery-draining super-bright backlights. That meant reducing the number of layers as each surface reflects sunlight back at the user, or bonding layers together to eliminate surfaces. And it also meant using anti-reflective (AR) and anti-glare (AG) coatings. These two measures combined made for impressive outdoor viewability even without a strong backlight (the Dell tablet we tested in 2017 offered 560 nits luminance).

560 nits made earlier Dell tablets nice and bright, but Dell apparently decided to amp up brightness anyway, and so the Latitude 7220 Rugged Extreme Tablet's display clocks in at an impressive 1,000 nits of luminance (RuggedPCReview measured 1,020 nits). For illustration, the pictures below are a side-by-side comparison between the 11.6-inch Dell screen and that of a 2nd gen Apple iPad Pro 12.9 we're using around the office for this and that.

In the first comparison image, both screens can easily be viewed outdoors, with the Dell tablet somewhat brighter than the iPad Pro 12.9, which is said to run at about 600 nits.

In the second comparison image, the tablets lay flat on the ground, facing the sky. Even in bright daylight both remain very readable, with the Dell again somewhat brighter. In the leftside picture, note the reflections on the glossy iPad display, whereas the semi-matte Dell display shows none.

The final picture below shows the Latitude 7220 Rugged Extreme Tablet outdoors, held so that it faces the sky. Note the total absence of reflections on the left side. That's a big plus of a semi-matte display. There is, however, always a tradeoff with current technology displays: on the right side you can see how the semi-matte display diffuses light instead of reflecting it back, as a glossy display would.

Dell knows that and that's the reason why their tablet has those physical control buttons to quickly adjust volume and screen brightness, toggle between portrait and landscape mode, and perform frequently used tasks with three programmable function keys.

While the buttons help augment the tablet experience on the hardware side, Dell's also addressing matters on the software side. That's where the "Rugged Control Center" app comes in. It includes a dashboard that can be populated with one-touch hardware controls and quick launch shortcuts, and also allows setting of the programmable hardware buttons (each has a short press and a long press function). There are also tabs for GPS status, overall system information, and settings.

Bottomline here is that today's users are spoiled by the excellent cameras built into smartphones and also by the sophisticated camera imaging apps that are available. The Dell tablet's cameras are not at that level and the Windows Camera app is marginal. The camera are, however, good enough for many documentation tasks, and certainly good enough for decent quality conferencing (which, of course, has become much more important as of late).

Tough enough for the field