CPU Performance

The heart of the Clover Trail advantage is really Intel’s two 32nm Saltwell Atom cores that are integrated into the Cloverview SoC. Each core is Hyper Threaded making the machine a 2 core, 4 thread beast similar to what we’ve seen from Intel’s other dual-core processors for years now. Despite the 32nm process, these Saltwell cores are direct descendants of the original Bonnell Atom core, first built at 45nm back in 2008. The fact that in five years the Atom core has only progressed by a single process node tells you a lot about how much of a priority this architecture has been for Intel. To Intel’s credit, Cloverview is built on an SoC process at Intel’s fabs that’s slightly different from the standard process used for the Core line of processors. Intel’s low power SoC process roadmap has historically lagged behind the high performance roadmap, although at some point in the not too distant future Intel expects these two to happen in near lockstep.

Medfield vs. Clovertrail
  Intel Atom Z2460 Intel Atom Z2760
Platform Codename Medfield Clovertrail
OS/Platform Target Android Smartphones Windows 8 Tablets
Manufacturing Process 32nm SoC (P1269) 32nm SoC (P1269)
CPU Cores/Threads 1 / 2 2 / 4
CPU Clock up to 2.0GHz up to 1.8GHz
GPU PowerVR SGX 540 PowerVR SGX 545
GPU Clock 400MHz 533MHz
Memory Interface 2 x 32-bit LPDDR2 2 x 32-bit LPDDR2

The fundamental architecture of each Atom core hasn’t changed. This is still a 2-wide in-order machine with a bunch of power and performance efficiency tricks that make it hit much higher than you’d otherwise expect. As you’ll see in the benchmarks to come, this five year old Atom architecture is still faster than every single ARM based core on the market today with the exception of the Cortex A15. Hampered mostly by really inefficient software and a lack of good platforms, Atom never really had the opportunity to shine in the past. Even with Windows 8 things are better but still not perfect for the soon-to-be-replaced core.

Each core features its own private 512KB L2 cache and can clock up to 1.8GHz. These cores could technically support 64-bit operation, but Intel specifies them as supporting the 32-bit x86 ISA. Windows 8 with Connected Standby (S0ix baby) support only currently exists in a 32-bit version, and Clover Trail is only designed to support Windows 8 at this point which is why these are effectively 32-bit cores.

Backwards compatibility is a major selling point for the Clover Trail platform as being able to run existing Windows applications is something no competing ARM platform can offer. There are two limitations however: 1) Keep in mind that this is still an Atom based SoC, so just because you can run (virtually) all applications it doesn’t mean they will perform well, and 2) These Atom cores only support SSE1/2/3/3S, the newer extensions to x86 aren’t supported (no SSE4 or AVX). The latter isn’t too big of a deal given that those extensions are rarely required for older applications, but it’s a distinction worth noting.

Despite looking at lot like Intel’s Medfield platform, Clover Trail does differ in some fundamental ways. Intel doesn’t have a lot of documentation about this but the memory controller on the Cloverview SoC has been significantly improved over Medfield. It better supports prioritizing GPU accesses to main memory, which in turn helps deliver a very smooth Modern UI experience in Windows 8. The Cloverview/Clover Trail memory controller enhancements will make their way into Medfield’s successor on the smartphone side, as well as future derivatives of Intel’s Atom for tablets.

I mentioned this in our initial Clover Trail analysis piece, but the SoC doesn't support SATA - only eMMC. Only USB 2.0 is supported as well.

As we make our way into 2013, at least on the Windows side of things, I'll be able to move away from js based performance comparisons between tablets. For now, we start off with some of the latest JavaScript tests we've been using in our mobile reviews. All of these were run in Modern IE10 on the Windows devices. I threw in some of our iPad 4 and Nexus 10 for comparison:

JavaScript Performance
Time in ms (Lower is Better) Kraken SunSpider RIA Bench Focus
Acer W510 (Atom Z2760 1.8GHz) 33220.9ms 730.8ms 3959ms
Microsoft Surface (Tegra 3 1.3GHz) 49595.5ms 981.1ms 5880ms
Samsung ATIV Smart PC (Atom Z2760 1.8GHz) 33406.0ms 721.3ms 3752ms
Apple iPad 4 (A6X) 19086.9ms 834.7ms -
Google Nexus 10 (Exynos 5 Dual) 11146.0ms 1384.1ms -

Although CloverTrail manages a win over all platforms in SunSpider, Kraken paints a different picture. In the case of the iPad 4 it's likely showing us browser performance superiority, while in the case of the Nexus 10 it's a combination of that and a simply faster pair of CPU cores.

Principled Technologies, apparently featuring some of the same folks who were responsible for building the old Winstone benchmarks from over a decade ago, actually put out the first cross platform Windows RT/8 benchmark with some help from Intel. Despite Intel’s influence the test appears to have no native code, instead relying on just a heavy workload of large images and videos for its tests.

TouchXPRT 2013
Time in Seconds (Lower is Better) Photo Enhance Photo Export Video Transcode MP3 Transcode Photo Slideshow Creation
Acer W510 (Atom Z2760 1.8GHz) 205.83s 73.0s 52.07s 96.02s 85.31s
Microsoft Surface (Tegra 3 1.3GHz) 306.12s 116.36s 87.27s 160.99s 125.06s
ASUS VivoTab RT (Tegra 3 1.3GHz) 312.14s 109.89s 89.69s 155.84s 122.65s

The PT folks also put together a suite of HTML5/js tests, once again giving us the opportunity to test cross-platform performance. As these tests are run in the browser, there's good opportunity for browser optimizations to play a role here as well as platform performance:

WebXPRT 2013
Time in ms (Lower is Better unless otherwise noted) Overall (higher is better) Photo Effects Face Detection Stocks Dashboard Offline Notes
Acer W510 (Atom Z2760 1.8GHz) 220 2437.2 ms 2590.3 ms 1091.5 ms 1832.4 ms
Microsoft Surface (Tegra 3 1.3GHz) 168 2790.7 ms 3482.1 ms 1696.3 ms 2288.1 ms
Apple iPad 4 (A6X) 182 4331.2 ms 4136.8 ms 786.0 ms 1942.6 ms

It doesn’t really matter where you turn, the CPU side of Clover Trail is clearly ahead of anything we’ve seen thus far in the Windows RT camp. Modern UI performance is great, clearly better than Surface, but the Windows 8 desktop experience falls short. UI performance can be sluggish in desktop mode. Scrolling through Control Panel animates at < 30 fps, the same goes for highlighting a group of icons on the desktop. Moving windows around tends to be pretty smooth however, which makes me wonder how much of the UI performance issues are driver related.

On the CPU side of things, you have to keep in mind this is still an Atom based platform. Although things have improved since the original Atom, we’re still talking about a fairly old architecture. Although you can run Photoshop or 3dsmax on here, I wouldn’t recommend it. As with the old netbooks, whether or not Atom is enough depends mostly on what you’re doing.

All of the Office 2010 applications ran wonderfully on the W510. They all launched reasonably quickly and were responsive. Outlook, a major component missing from the Windows RT experience, had no problems running on the W510. The experience does suffer the moment you try to run something truly CPU intensive (by modern notebook standards), but for light office work the W510 excels.

The high CPU utilization under Word 2013 does still exist even on Clover Trail:

I ran our Excel MonteCarlo simulation script on the W510 to get an idea of how a hefty Office workload would fare on the tablet. The result was surprisingly decent thanks to hardware support for 4 threads, but still much slower than a modern CPU:

Microsoft Excel 2007 SP1 - Monte Carlo Simulation

To really put the W510's performance in perspective I compared it to a handful of notebooks:

PCMark 7 - PCMarks

Better performance than AMD's original Brazos platform isn't bad, but in the grand scheme of things you're looking at a much slower system than anything Core based. The W510 comes surprisingly close to the Llano based Toshiba P755D, but I suspect a big part of that is the storage solution. The blessing and curse of the W510 is that it does use solid state storage, so performance will never be as bad as the old netbooks that used 5400RPM hard drives. The solid state storage comes in the form of an eMMC solution, which doesn’t do a great job of delivering high random IO performance.

The Display GPU Performance
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  • Pirks - Saturday, December 22, 2012 - link

    I noticed serious differences in user experience between Win8 tablets bought at MS retail store and elsewhere. Anand went for the worst possible scenario and got tablet stuffed with crapware instead of buying a tablet at MS store, online or retail, WITHOUT any crapware. Guys, PLEASE bear this in mind when reading this review. THIS REVIEW IS NOT, I EMPHASIZE THIS AGAIN - _NOT_ REFLECTING REAL END USER EXPERIENCE AS ENVISIONED BY MICROSOFT. In other words, standard stores AT buys its review hardware from and MS stores are DIFFERENT things.

    Please, KEEP this in mind when reading this review. It is VERY likely that you will see quite a difference between experiences using two same tablets bought in different stores, MS and non-MS one. I've seen it by own eyes when for example comparing how responsive the OS is, and how stylus works on ATIV Smart PC bought on Amazon versus the one bought in MS online store.

    In the end, if you buy hardware not in MS store and see some issues - quite likely it is now YOUR issue, not Microsoft's. MS is offering people retail and online stores to buy clean reliable crapware-free Windows hardware. If you buy elsewhere - you must be dumb. End of story.

    Anand, please consider what I said above. I am serious, no trolling or anything here. You are one of the best tech reviewers on the net. You should strive for better, so please think again where are you buying your review units in the future. PLEASE. Thank you.
    Reply
  • Death666Angel - Saturday, December 22, 2012 - link

    I don't believe I am even dignifying your comment by commenting on my own. Firstly, I didn't find an online MS store that would sell me a W510 in Germany. Amazon.de has that. Secondly, you say it is all worse, yet you only talk about crapware, which Anand mentions in a few paragraphs but has no bearing on his conclusion or any of the real numbers (performance, battery life...). So your post screams either "bought" or "troll" to me. Reply
  • Ned - Saturday, December 22, 2012 - link

    Ive just had confirmed that the first batch of Acer W510 optional Keyboard docks have a faulty touchpad which is fixable by any Acer service centre.
    All new batches from Acer have this now fixed.
    Also, if you have one of the original first production W510, make sure you update the BIOS which is available on the Acer website.
    Reply
  • powerarmour - Sunday, December 23, 2012 - link

    And yet again Intel fail to deliver a quality GPU driver for PowerVR series hardware, how many times will customers be forced to put up with this mess?

    The reason why a Tegra 3 is more responsive is that at least Nvidia know how to write a driver that isn't a buggy mess, even the fact that Clover Trail is x86 means little at this level of dire performance, what the hell are you going to run on it that you can't already do on a WinRT platform?
    Reply
  • agentsmithitaly - Sunday, December 23, 2012 - link

    Dear Anand
    I know it has been already already debated, but measurement units are quite inconsistent in Anandtech's articles.
    Sometimes they report both Celsius and Fahrenheit for temperatures, as well as inches and millimeters for length measurements, in this case we see imperial units for dimensions and weight comparision, dock and tablet weight in grams, millimeters for keyboard keys. Of course it's perfectly fine to express display size, or storage unit size in inches as it is the de-facto standard.

    Is it possible to have International system of units on all articles? Not only for the international visitors I'm sure Anandtech has, but also because this is technology website, which I think it could be considered as science. And scientists use metrical units, including NASA ones. You remember what happened to the Mars Climate Orbiter, right?

    Apart this, keep up the good work guys! And Merry Christmas to all!
    Reply
  • yannigr - Monday, December 24, 2012 - link

    We NEED AMD solutions. Pity AMD is for far behind. A tablet with for balanced hardware would have been great. Reply
  • zeo - Monday, December 31, 2012 - link

    Yes, though AMD is releasing the Z-60 Hondo as a stop gap for now. Being a slight update to the previous Z-01 Desna, which itself was just a more power optimized version of the C-50 Ontario.

    2013 though will see AMD's 28nm updates, with the newer Jaguar CPU cores.

    Specifically, for tablets, the upcoming 2W max TDP SoC AMD Tamesh will be their first serious entry into the tablet market and we'll see then how they compare.

    For now, the Hondo is at least a option for those who don't mind limited run time but want 3x better graphics than Clover Trail, which also puts it above Tegra 3 graphical performance, and full 64bit and better Linux support.

    At 1GHz though, don't expect better CPU performance...
    Reply
  • OBLAMA2009 - Monday, December 24, 2012 - link

    i think all these windows 8 tablet/notebook thingies will be a huge fail. carrying something with all these parts isnt more convenient that just using different devices or using chromeos and doing things in the cloud. atom is a seriously damaged brand name because of low performance and this new stuff doesnt change that. finally the prices for stuff like this are ridiculous. were used to paying $350 for laptops, we arent going to pay $600 for stuff a tenth as good Reply
  • zeo - Monday, December 31, 2012 - link

    First, there aren't that many parts and overall it is more convenient to carry one device than multiple... especially, if your actual usage favors tablet usage most of the time.

    Second, people have being paying such prices for iPads for years, a lot more when you consider the cost of peripherals, and ARM has only recently gotten around the performance range of a ATOM!

    Tablets are typically higher priced than laptops, though Ultrabooks puts a premium that lessens the difference a bit.

    People though have and will pay for the convenience of mobility, which laptops can only be considered to be portable but not truly mobile. While tablets can provide mobile usage, along with hybrids and other solutions retaining most, if not all, of the benefits of laptops as well.

    It's just that there's always compromise when going smaller and lighter, and no solution is perfect for everyone! Along with it yet being determined what size the actual market will be, as these are first gen Windows based devices and many are just waiting for the pro and second gen products.

    So it's comparing apples to oranges with tablets and laptops, different solution for people with different needs!

    Btw, even Chromebooks require a certain level of performance. Cloud doesn't run everything and you can't always have a high speed connection, which is one of the reasons why Chrome OS has a native client and support for hardware acceleration!

    The Cloud isn't that reliable yet either and not everything can be replaced by Cloud apps yet. Though such services are getting better and help alleviate the limitations of these mobile devices.
    Reply
  • mhaager2 - Monday, December 24, 2012 - link

    I don't really understand all the negativity towards Win RT and the Surface RT in particular. We have an iPad3, a nexus 7, and now a surface RT in our house. Hands down I like my Surface RT the best. It is by far the best of all in terms of productivity. I like the OS a lot. Its stable, responsive, and a pleasure to use. I like the touch cover a lot. I can type well enough on it to be useful without being a hassle to lug around. I have never experienced lag with it yet.
    Could MS improve the Surface? Of course. A higher DPI screen would be nice. A faster CPU is always nice. A lower price would be nice. Still despite all of this I still find this the most useful tablet I have used. As far as the paucity of apps goes, I think having half a million apps in your app store means a LOT of redundancy. MS is missing some key apps for me unfortunately which means I can't go to Win8 phone yet but as long as they keep adding quality apps I think this is the platform for me going forward.
    Reply

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