the Surface RT is that, since it is an ARM based Tegra 3 device surface rt, arm tegra 3

One of the primary criticisms of the Surface RT is that, since it is an ARM based Tegra 3 device, it does not run traditional x86 apps. That's likely also why it comes with a bundled version of Office 2013. Well, the Yoga 13 resolves that complaint, because it's a Core i5 Ivy Bridge machine. But there is a cost for this x86 compatibility:

The size comparison isn't entirely fair, since the Yoga is a 13.3" device, and the Surface is a 11.6" device. But Surface Pro has x86 internals and is otherwise as identical to the Surface RT as Microsoft could possibly make it, and it's still 44% larger and 33% heavier. Intel inside comes at a hefty cost in weight, battery life, and size.

You do get something for that price, though: compatibility with the vast library of x86 apps, and speed. The Yoga 13 is absurdly fast by tablet standards. Its Sunspider score is approximately 150 ms, compared to my iPad 4 at 738 ms, and the Surface RT at 1036 ms. Five hours of battery life might not seem like such a bad tradeoff for six times the performance.

I like the Yoga 13 a lot, and it is getting deservedly good reviews. Some reviewers think it's thebest Windows 8 laptop available right now. It is a fine replacement for my ultrabook, and as long as you fix the brain-damaged default drive partitioning, scrape off the handful of stickers on it, and uninstall the few pre-installed craplets, it is eminently recommendable. You can also easily upgrade it from 4 GB to 8 GB of RAM for about $40.

But there were things about the practical use of a touch laptop, subtle things that hadn't even occurred to me until I tried to sit down and use one for a few hours, that made me pause:

• The screen bounces when you touch it. Maybe I just have hulk-like finger strength, but touching a thin laptop screen tends to make it bounce back a bit. That's … exactly what youdon't want in a touch device. I begin to understand why the Surface chose its "fat screen, thin keyboard" design rather than the traditional "thin screen, fat keyboard" of a laptop. You need the inertia on the side you're touching. The physics of touching a thin, hinged laptop screen are never going to be particularly great. Yes, on the Yoga I can wrap the screen around behind the keyboard, or even prop it up like a tent – but this negates the value of the keyboard which is the biggest part of the touch laptop story! If I wanted a keyboardless tablet, I'd use one of the four I have in the house already. And the UPS guy just delivered a Nexus 10.
• A giant touchpad makes the keyboard area too large. On a typical laptop, a Texas size touchpad makes sense. On a touch laptop, giant touchpads are problematic because they push the screen even farther away from your hand. This may sound trivial, but it isn't. A ginormous touchpad makes every touch interaction you have that much more fatiguing to reach. I now see why the Surface opted for a tiny touchpad on its touch and type covers. A touchpad should be a method of last resort on a touch laptop anyway, because touch is more convenient, and if you need true per-pixel precision work, you'll plug in a mouse. Have I mentioned how convenient it is to have devices that accept standard USB mice, keyboards, drives, and so on? Because it is.
• Widescreen is good for keyboards, but awkward for tablets. A usable keyboard demands a certain minimum width, so widescreen it is; all touch laptops are going to be widescreen by definition. You get your choice between ultra wide or ultra tall. The default landscape mode works great, but rotating the device and using it in portrait mode makes itsuper tall. On a widescreen device, portrait orientation becomes a narrow and highly specialized niche. It's also very rough on lower resolution devices; neither the 1366×768 Surface RT nor the 1600×900 Yoga 13 really offer enough pixels on the narrow side to make portrait mode usable. You'd need a true retina class device to make portrait work in widescreen. I began to see why the iPad was shipped with a 4:3 display and not a 16:9 or 16:10 one, because that arrangement is more flexible on a tablet. I frequently use my iPad 4 in either orientation, but the Yoga and Surface are only useful in landscape mode except under the most rare of circumstances.
• About 11 inches might be the maximum practical tablet size. Like many observers, I've been amused by the race to produce the largest possible phone screen, resulting in 5" phablets that are apparently quite popular. But you'll also note that even the most ardent Apple fans seem to feel that the 7" iPad mini is an inherently superior form factor to the 10" iPad. I think both groups are fundamentally correct: for a lot of uses, the 3.5" phone really is too small, and the 10" tablet really is too big. As a corollary to that, I'd say anything larger than the 11.6" Surface is far too large to use as a tablet. Attempting to use the 13.3" Yoga as a tablet is incredibly awkward, primarily because of the size. Even if the weight and volume were pushed down to imaginary Minority Report levels, I'm not sure I would want a 13.3" tablet on my lap or in my hands. There must be a reason the standard letter page size is 8½ × 11", right?
• All-day computing, or, 10 hours of battery life. The more devices I own, the more I begin to appreciate those that I can use for 8 to 10 hours before needing to charge them. There is truly something a little magical about that 10 hour battery life number, and I can now understand why Apple seemed to target 9-10 hours of battery life in their initial iPad and iPhone designs. A battery life of 4 to 6 hours is nothing to sneeze at, but … I feel anxiety about carrying the charger around, whether I've charged recently or not, and I worry over screen brightness and other battery maximization techniques. When I can safely go 8 to 10 hours, I figure that even if I use the heck out of the device – as much as any human being reasonably could in a single day – I'll still safely make it through and I can stick it in a charger before I go to bed.