Economically priced rugged Intel "Bay Trail" powered 8.0-inch Windows 10 tablet for the mobile workforce, no matter where it's deployed
by Conrad H. Blickenstorfer

On December 1, 2015, MobileDemand officially announced the 8-inch xTablet T8500 and the 10.1-inch T1500, adding two more members to its already comprehensive family of thin and light rugged tablets. The two new xTablets fit between the company's low-cost xTablet Flex models and the fully rugged high-end xTablet T1200, T1400 and T1600 tablets. In this article we're reviewing the xTablet T8500 in detail.

Where does the new xTablet T8500 fit in? Those familiar with MobileDemand know that after years of primarily offering fully rugged high end tablets, in 2014 the company introduced the economically priced "Flex" line — standard consumer/business Windows tablets prepackaged in a competent protective case with bumpers and a carry handle, and a scratch-proof screen protector. Well, the xTablet T8500 again is a value price offering, but one that's more rugged, carries much higher environmental sealing, and can be ordered with an optional barcode scanner.

The lineup below provides a quick idea of how the new tablet visually compares to some of the other MobileDemand products. The xTablet T8500 has the same size display as the low-end Flex 8 (middle left) and is in the same overall size class. The company's higher-end 10.1-inch thin & light xTablet T1400 (middle right) is noticeably larger. On the right is the older fully rugged T7200 (right) with a wide-format 7-inch screen and keypad.

Side-by-side, the size and design differences become obvious. And each product clearly fills a purpose and need.

How's the xTablet T8500 different from the Flex 8?

MobileDemand Model	xTablet T8500	xTablet Flex 8
Introduced	12/2015	12/2014
Display (inches/resolution)	8.0/1280 x 800	8.0/1280 x 800
Size (inches)	9.0 x 5.8 x 0.65	8.8 x 5.6 x 0.7
Weight	1.4 lbs	1.6 lbs
Processor Type	Intel Atom Z3735F	Intel Atom Z3775
Processor Codename	"Bay Trail"	"Bay Trail"
CPU Speed (base/burst)	1.33/1.83GHz	1.46/2.39GHz
Cores/threads	4/4	4/4
RAM	2GB DDR3L-RS 1333	4GB LPDDR3 1066
Storage	64GB	64GB
Sealing	IP67	not sealed
Operating temp.	-4° to 140°F	32° to 120°F
Scanner	Yes (opt.)	No
GPS	Yes	No
Battery	30.7 whr ("8 hours")	17.5 whr ("4.5 hours")

The new xTablet T8500 and T1500 (which we're in the process of reviewing in detail as well), while still very affordable by rugged tablet standards, take a substantially different design approach. We'll get into that in detail farther down when we take a look inside the xTablet T8500.

The table to the right shows some of the relevant specs of MobileDemand's two 8-inch tablets. As can be seen, they have the exact same screen size and resolution, weigh roughly the same, and have roughly the same dimensions.

Both use low-end quad-core chips from Intel's "Bay Trail" lineup. The chip used in the xTablet T8500 is a bit slower and there's only half as much RAM. So in terms processor and RAM, the xTablet T8500 is a bit behind the Flex 8.

In terms of ruggedness spec, however, the xTablet T8500 has it all over the Flex 8. IP67 sealing versus none, much wider operating temperature range. And the xTablet T8500 has a true scanner and not just a camera that can run scanner apps. There's GPS. And there's a much more powerful battery that makes full shift operation possible. The latter alone can tilt the scale in favor of the xTablet T8500, as today's customers generally expect 8 to 10 hours of battery life on a charge.

Handy, tough and light

Note that the xTablet T8500 does not need a fan and uses solid state storage instead of a rotating hard disk, so it operates silently. Also note that despite its small size, the bezel areas to the left and right of the actual LCD display are wide enough to offer a palm and thumb resting area without interfering with operation.

A look inside: very different from the Flex models

Those who dare to open up the xTablet T8500 are in for a big surprise. Including us here at the RuggedPCReview lab. As already mentioned above, we had fully expected MobileDemand to take the same approach as they had with their Flex 8 and Flex 10 models, i.e. packaging a generic white box tablet in a tough and rugged protective enclosure, only in the case of the xTablet T8500 and T1500 a more permanent and even tougher one.

Amazingly, what reveals itself upon undoing about 20 little Torx T6 screws is conventional rugged tablet fare, i.e. a tough ABS plastic box with a rear cover plate of the same footprint. The seal between the two housing parts consists of an intricate rubber pressure seal that sits in an elaborate groove around the perimeter of the bottom plate. A corresponding thin hard plastic lip on the box part of the housing presses into the rubber to form the seal. The rubber seal appears to be replaceable and it doesn't easily come loose. This is a well thought out solution.

Below you can see what the xTablet T8500 looks like inside:

Inside, the xTablet T8500 doesn't have an elaborate magnesium or alloy chassis/frame as most high end rugged tablets have. Instead, a simple aluminum plate provides the basis for the LCD on the front side and the battery and circuit boards on its rear.

There isn't a battery compartment per se. Instead, the non user-replaceable 3.7 Volt, 8,500mAH battery, packed in the kind of blue shrink-wrap plastic seen in various consumer gadgets, is glued onto the frame. Replacement is possible, but should be left to the service department.

The motherboard itself measures about 3.25 x 4.5 inches.There's not much to be seen on it as a good half of its surface is covered by a black shield or heat spreader. Black fabric tape is used liberally to protect connectors and other small details and keep them in place. White silicone glue is used to seal any potential openings to the outside, as well as glueing and sealing the small speaker.

The colorful picture to the right was taken with our Flir One infrared camera. It shows the thermal situation inside the xTablet T8500, with darker areas the coolest and bright yellow the hottest. Since the xTablet T8500 doesn't have a fan to remove heat, good thermal management is essential. As can be seen, the area where the xTablet T8500's processor resides is hottest, but the design can easily handle it. In operation, the xTablet T8500 barely warmed up in our testing.

Most I/O is edge-mounted on the motherboard, which means it's fixed. Higher end devices often have part of their I/O on daughterboards, which offers flexibility as customers may be able to specify optional I/O.

The image on the left shows the xTablet T8500's integrated Fibocom Wireless H350 module (see here) that supports legacy GSM/GPRS/EDGE and 3.75G UMTS, HSDPA, HSUPA, HSPA+.

As is usually the case even in rugged devices, the protective rubber doors are the sole guard against liquids entering the interior of the case. We don't like to see that, but it's the standard solution today. So always keep an eye on those protective doors before using the tablet in the field. The good news is that the doors are screwed on and can be replaced should they get worn or damaged.

And speaking of protective features, while the contoured corner guards look like they are screwed on and replaceable, they're really glued onto the rear cover of the xTablet T8500.

Overall, this is a very workable solution. It shows that with some thought and good design, even economically priced solutions can provide very good stability and sealing.

Intel "Bay Trail" processor

Computing power comes from a 1.33GHz quad-core Intel Z3735F processor that can reach burst speeds up to 1.83GHz. It belongs to Intel's "Bay Trail" platform that employs 22nm process technology and represents a major advance in Atom microprocessor design, the first since the platform arrived several years ago. Note that turbo boost is called "burst frequency" in the Bay Trail lineup, and that an implementation of the clever power-saving "active idle" feature from Haswell core processors is apparently there as well.

That said, the Bay Trail processor platform is somewhat confusing as it includes not just Atom but also Celeron and even Pentium branded chips. The N2920 used in MobileDemand's xTablet T1400, for example, is sold by Intel as a Celeron whereas Intel lists the xTablet T8500's Z3735F as an Atom. For full Z3735F specs, see Intel's Z3735F product sheet.

While even detailed examination of Intel's literature provides few clues as to what the relevant, real-world differences are between the various Bay Trail processor lines, it does appear that Intel views the Z-Series as suitable for lower cost tablets and perhaps even smartphones, whereas the significantly more costly N-Series is for higher end tablets.

PassMark 6.1	MobileDemand	MobileDemand	MobileDemand
Model	xTablet T8500	xTablet Flex 8	xTablet T1400
OS	Win 10 (32-bit)	Win 8.1 (32-bit)	Win 8.1 (64-bit)
Processor Type	Intel Atom	Intel Atom	Intel Celeron
Processor Model	Z3735F	Z3775	N2920
CPU Speed	1.33Hz	1.46Hz	1.86Hz
Max Burst Speed	1.83Hz	2.39Hz	2.00Hz
Scenario Design Power (SDP)	2.2 watts	2.0 watts	4.5 watts
CPU Mark	1,115.1	1,589.5	2,014.7
2D Graphics Mark	112.7	178.2	153.1
Memory Mark	283.2	421.1	409.9
Disk Mark	902.7	288.0	2,048.3
3D Graphics Mark	99.2	147.4	115.3
Overall PassMark	560.3	605.2	1,062.7
CrystalMark
ALU	20,734	29,126	26,714
FPU	17,523	24,532	22,541
MEM	19,712	25,540	16,411
HDD	24,812	10,649	36,655
GDI	3,790	5,682	4,816
D2D	2,800 (est)	3,527	3,335
OGL	2,448	3,454	3,207
Overall CrystalMark	91,819	102,412	113,679

Another somewhat irritating development is that Intel has started to use SDP ("Scenario Design Power") sometimes instead of and sometimes in addition to the more common TDP ("Thermal Design Power"). TDP indicates the maximum amount of heat in watts a system's cooling must be able to remove, giving a pretty good indication of the chip's overall performance, whereas SDP is the amount of heat to be removed under benign conditions, i.e. standard tablet apps and no temperature extremes.

"Burst speed," likewise, is just the speed the processor may reach under ideal conditions. We take this as meaning that if things get hot, the chip slows down.

On the plus side, the graphics cores integrated into Bay Trail systems are of the same HD 4000 architecture and variety as those used in Intel's 3rd generation "Ivy Bridge" processors, albeit with fewer execution units (four instead of several times that number) and lower clock speeds. Still, that means the new graphics support most of the same APIs and features.

As is, the table above shows our benchmark results for the Z3735F-based xTablet T8500, the Z3775-based xTablet Flex 8, and the N2920-based xTablet T1400. When we tested the Flex 8 a while ago, MobileDemand had told us their benchmarks showed the higher-end T1400's CPU performance about 20% better than the Flex 8's, with 2D graphics about 15% better and 3D graphics 7-10% better. Our own numbers agreed on the CPU, but the Flex 8 more than held its own in memory and graphics performance. So how did the xTablet T8500 do?

It's never totally clear to us how vendors pick one chip and not another. As is, the Z3735F, while sharing most of its specs with the Z3775 used in the Flex 8, is a lower-end processor with lower base and burst clock speeds, a different type of memory, and only one instead of two memory channels. And its maximum graphics speed is lower, too. All that is reflected in our benchmark results where the xTablet T8500 can't quite match the surprisingly speedy Flex 8.

There is, however, one area where the xTablet T8500 easily trumps the Flex 8, and that is disk performance. That's because the Flex 8 uses comparatively slow eMMC solid state storage whereas the xTablet T8500 uses quicker mass storage technology. That helps the xTablet T8500 to considerably close the gap to the Flex 8, but it's still about 10% slower overall.

That's not to say, however, that the xTablet T8500 is slow. It can't, of course, match the performance of a much more expensive Intel Core-powered device, but it never felt sluggish. And, in fact, the xTablet T8500 scored almost twice the benchmark performance of MobileDemand's high-end flagship T8700 of just a few years ago.

Excellent IPS 1280 x 800 pixel capacitive multi-touch display

While the xTablet T8500's processor and memory makes performance concessions in the interest of affordable pricing, the tablet's display certainly does not. Measuring a compact but not too small 8 inches diagonally — it's noticeably larger than the 7-inch screen of MobileDemand's ultra-rugged xTablet T7200 — it offers perfectly matched WXGA resolution. That's 1280 x 800 pixel in 16:10 wide-format — 30% more pixel that the 1024 x 768 XGA format that was commonly used in rugged tablets (even ones with larger screen sizes) for many years, and is still being used today.

On a 8-inch tablet screen, that translates into 190 dots per inch (dpi), which means it's sharper than, say, Dell's terrific 24-inch UltraSharp 4k monitor, and much sharper than the original iPad. The xTablet T8500 uses 5-point projected capacitive multi-touch for effortless tapping, panning, pinching and zooming, plus executing whatever complex operations need more than just a couple of fingers. And the display, which feels brighter than its listed 320 nits luminance rating, is of the IPS (in-plane switching) variety that makes for perfect viewing from all angles.

MobileDemand supplies a capacitive pen with a foot-long lanyard. The pen is of the passive capacitive variety and has the broad tip that works well for tapping and panning, but not for precision work. To MobileDemand's credit, they replaced the usually short and chintzy generic capacitive pens with their rubber tips with a metal mesh tipped stylus that is, albeit still rather wide, more durable, works somewhat better, and is longer and thicker than generic styli. And they also used their standard and very durable tether and stylus holder to store the pen when it's not in use.

It's interesting that until recently capacitive touch was considered unsuitable for rugged tablets, in part because of the technology's inability to work with gloves and in part because Microsoft Windows, unlike iOS or Android, simply wasn't designed for finger touch. Today, most new rugged tablets use capacitive touch, mostly because customers, who all use capacitive touch smartphones and tablets at home, simply demand it. Add to that Microsoft's efforts to make Windows more touch-friendly and the increasing availability of capacitive touch-enabled gloves, and it absolutely made sense for MobileDemand to go this route.

That said, the legacy Windows user interface isn't a perfect match for use with capacitive touch. On high-end tablets that's usually addressed with including a Wacom-style active pen, but that's costly and thus beyond the scope of a low-cost rugged tablet.

Workable dual cameras

The xTablet T8500 has two integrated cameras. The user-facing 2mp camera is for video conferencing, whereas the rear-facing 5mp camera with LED flash can be used for documentation purposes.

Cameras integrated into handheld and tablet computers have historically underperformed compared to even low-end dedicated cameras and, more recently, the cameras available in virtually every smartphone. Things have gotten better on the built-in camera front, but usually not enough to eliminate the need of taking along a dedicated camera or smartphone if photo or video documentation is needed on the job. This remains a concern given that the cameras in leading smartphones are now capable of excellent picture and video quality.

As is, we didn't really have adequate opportunity to fully examine the capabilities of the xTablet T8500 cameras. That's because the default imaging app only offered very basic functionality, and so we couldn't test all the usual settings. System integrators and most customers will likely want more comprehensive software ith all the usual settings.

In our testing, still images defaulted to 2560 x 1440 pixel, and video to 1920 x 1080, also known as 1080p. In still photography, auto-focus worked fine, images are reasonably sharp, and the camera does not over-compress images. Video was sharp enough for almost all purposes and did not lag behind.

The front camera, though capable of 2-megapixel images, defaulted to 1280 x 720 pixel (720p). It worked more than well enough for conferencing.

Below are pictures shot with the xTablet T8500 camera in 2560 x 1440 pixel resolution. To see a full-size image of the compilation, click on the picture.

Remarkable ruggedness

Here it gets interesting. Unlike the Flex 8 which is a consumer-grade tablet neatly protected inside a customized rugged case, the xTablet T8500 is a rugged tablet, albeit one that costs far less than most. What can it do that the already quite impressive Flex 8 can't do?

Well, the drop spec is the same. MIL-STD 810G, 516.6 IV, which mandates 26 repeated drops to one operating unit onto plywood over concrete from 48 inches. That's the gold standard in the industry. Why? Because if a tablet is dropped while it's being used in a standing or walking position, it'll drop about four feet. The xTablet T8500 can handle that.

MobileDemand says that you can also drop an 8-ounce steel ball from a meter onto its screen and it won't get hurt due to the special screen protector (we didn't try that!).

The operating temperature range is -4° to 140°F, much wider than the somewhat restrictive 32° to 120°F range of the Flex 8. That covers virtually any application out there, even if it involves freezers or outdoor use in nordic climates.

The biggest difference between the xTablet T8500 and the Flex 8 is sealing. Despite its protective casing and nicely implemented protective rubber plug for all I/O ports, the Flex 8 isn't considered a sealed unit and does not have an IP rating. That means no working in the rain. The xTablet T8500, on the other hand, carries a stellar IP67 rating. That means it's totally dustproof and can also handle full immersion in water. Down to about three feet, for a full hour.

The picture below shows the xTablet T8500 during an outdoor photo shoot in the mid-teens. It already passed its immersion tests and is now sitting, literally, on thin ice, with fish looking at this unusual techno visitor from below.

So while the xTablet Flex 8 looks like a fully rugged device but really is a consumer tablet inside an intelligently designed case system, the xTablet T8500 is a rugged tablet. No asterisks. Given that, however, we would like to see more detailed ruggedness specs. Most customers will want that, as ruggedness is the primary reason for a device like the xTablet T8500, and test results should be readily available.

Mounting and docking options

Most tablets used in business or on the job come with some kind of docking and mounting options, and the xTablet T8500 is no different. While MobileDemand does not (yet?) offer the vehicle docks available for most of its higher end tablets, a nice office dock is listed for the xTablet T8500.

A big advantage here is that the office dock can actually be used for both the 8-inch xTablet T8500 as well as for the larger xTablet T1500. It's designed to accommodate an external monitor, keyboard and mouse, and it also has an RJ45 LAN port for wired Ethernet connectivity.

Given its small size and rugged design, the xTablet T8500 would also be a natural for use in vehicles with a quick-release mount, or as a fixed mount in all sorts of deployments. So we hope to see those as well.

As is, the tablet has two screw holes on its backside that are the VESA-standard 75 mm apart, but VESA generally uses for screws, so we'll have to report on this as we find out. This would allow customers to use any RAM-Mount implementation.

Bottom line: MobileDemand xTablet T8500

With the xTablet T8500, MobileDemand complements their existing and similarly sized Flex 8 with a device that ratchets ruggedness up by a good degree, while still keeping costs remarkably low.

Unlike the Flex 8 where MobileDemand prepackaged a generic tablet with a reinforced custom case, the xTablet T8500 is a rugged tablet from the ground up. And it can also be equipped with an integrated industrial-grade scanner, something which is mandatory in many deployments.

Weighing just a pound and a half, no more than the original iPad, MobileDemand's xTablet T8500 provides a second alternative for customers who want the convenience, low cost and ease of use of a consumer media tablet in package that's much better protected but still doesn't cost nearly as much as a conventional fully rugged tablet.

Making this possible required some, but remarkably few, concessions. The xTablet T8500's quad-core Intel "Bay Trail" processor is basic (but still provides about twice the performance of MobileDemand's flagship T8700 tablet of just a few years ago).

The xTablet T8500 impresses with an very sharp, bright and vibrant display that offers well-matched 1280 x 800 pixel resolution, a perfect viewing angle from all directions, and no color shifts. Its 5-point capacitive multi-touch screen is quick and very responsive, and works well with Windows 10 and touch-optimized applications. The included capacitive stylus has the usual broad tip, but it's of the metal mesh variety and works quite well.

For an inexpensive thin-and-light tablet the xTablet T8500 has adequate onboard connectivity, including USB host and client ports, and micro-HDMI. The 2mp and 5mp cameras are good enough for conferencing and documentation.

The tablet's rubber and polycarbonate casing is simple and well designed, protecting the innards of the xTablet T8500 from damage and leakage. It is very well sealed, and the operating temperature range of the tablet is wide enough for virtually any application.

All of this makes the fanless xTablet T8500 a compelling and very competitively priced package for anyone who needs Windows on tough jobs, even those that require high-level sealing, GPS, and industrial-grade scanning. -- Conrad H. Blickenstorfer, February 2016

MobileDemand xTablet xTablet T8500

Type	Rugged tablet computer
Added	Added 12/2015, full review 01/2016
Processor	Quad-core Intel "Bay Trail" Z3735F
Processor speed	1.33GHz, 1.83GHz burst frequency
Scenario Design Power	2.2 watts
Display Chipset	Intel HD Graphics Gen7 (4EUs)
OS	Windows 10 Professional or Home (32-bit)
Memory	2GB DDR3L
Display	TFT LCD with 320 nits LED backlight
Display size/res	8-inch, 1280 x 800 pixel
Digitizer	5-point capacitive multi-touch/capacitive stylus
Keyboard	Onscreen keyboard + optional external
Storage	64GB
Expansion slots	1 x micro SD
Housing	Polycarbonate housing with integrated protective rubber bumpers, aluminum internal frame
Size	9.0 x 5.8 x 0.65 inches (228 x 147 x 17 mm)
Weight	1.53 lbs. as tested
Operating temperature	-4° to 140°F (-20° to 60°C)
Ingress protection	IP67
Drop/shock	MIL-STD 810G, 516.6 IV: 26 repeated drops to one operating unit onto plywood over concrete from 48 inches
Tumble	unknown
Vibration	Unknown
Regulatory	FCC Class B, FCC/SAR, cUS, CE, CB, TUV, UL, NOM
Power	Internal non user-replaceable 3.7V 8,300mAH 30.7 watt-hour Li-Polymer ("8 hrs")
Cameras	2mp camera front, 5mp AF camera with LED flash rear (up to 2592 x 1944 pixel)
Sensors	Ambient light, G-sensor
Interface	1 x USB 2.0, 1 x Micro USB, 1 x Mini HDMI, headphone jack, power, docking
Wireless	802.11 a/b/g/n WiFi, Bluetooth 4.0, GPS, optional: NFC, 1D/2D scanner
Price	Starting at US$845, US$1,245 fully loaded
Warranty	1 year limited warranty
Contact	MobileDemand xTablet T8500 web page
Contact	MobileDemand xTablet T8500 specs (PDF)

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