CPU Performance

The big news with Tegra 3 is that you get four ARM Cortex A9 cores with NEON support instead of just two (sans NEON) in the case of the Tegra 2 or most other smartphone class SoCs. In the short period of time I had to test the tablet I couldn't draw many definitive conclusions but I did come away with some observations.

Linpack showed us healthy gains over Tegra 2 thanks to full NEON support in Tegra 3:

Linpack - Single-threaded

Linpack - Multi-threaded

As expected, finding applications and usage models to task all four cores is pretty difficult. That being said, it's not hard to use the tablet in such a way that you do stress more than two cores. You won't see 100% CPU utilization across all four cores, but there will be a tangible benefit to having more than two. Whether or not the benefit is worth the cost in die area is irrelevant, it only means that NVIDIA (and/or its partners) have to pay more as the price of the end product to you is already pretty much capped.

SunSpider JavaScript Benchmark 0.9.1

Rightware BrowserMark

The bigger benefit I saw to having four cores vs. two is that you're pretty much never CPU limited in anything you do when multitasking. Per core performance can always go up but I found myself bound either by the broken WiFi or NAND speed. In fact, the only thing that would bring the Prime to a halt was if I happened to be doing a lot of writing to NAND over USB. Keyboard and touch interrupts were a low priority at that point, something I hope to see addressed as we are finally entering the era of performance good enough to bring on some I/O crushing multitasking workloads.

Despite having many cores at its disposal, NVIDIA appears to have erred on the side of caution when it comes to power consumption. While I often saw the third and fourth cores fire up when browsing the web or just using the tablet, NVIDIA did a good job of powering them down when their help wasn't needed. Furthermore, NVIDIA also seems to prefer running more cores at lower voltage/frequency settings than fewer cores at a higher point in the v/f curve. This makes sense given the non-linear relationship between voltage and power.

From a die area perspective I'm not entirely sure having four (technically, five) A9 cores is the best way to deliver high performance, but without a new microprocessor architecture it's surely more efficient than just ratcheting up clock speed. I plan on providing a more thorough look at Tegra 3 SoC performance as I spend more time with a fixed Prime, but my initial impressions are that the CPU performance isn't really holding the platform back.

A Lesson in How Not to Launch a Product Tegra 3 GPU: Making Honeycomb Buttery Smooth
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  • joe_dude - Thursday, December 01, 2011 - link

    Sorry Anand, but could you clarify what you mean by "getting actual work done"?

    I don't expect the Transformer Prime to be running Photoshop (although Photoshop Touch is available?) or any intense apps. But is it a "good enough" laptop for a general user?
    Reply
  • Anand Lal Shimpi - Thursday, December 01, 2011 - link

    Browsing the web is still faster on an MBA/ultrabook, pages load quicker, you can open multiple tabs and load them in the background more effectively - you can switch between tasks quicker (cmd+tab/alt+tab is still infinitely more responsive than what you get with Honeycomb's task switcher). You can get writing done on both, but multitasking and being productive is just easier on a MBA/ultrabook.

    Now both of those comparisons are ~2x the price of the Prime. Compared to a netbook, I'd definitely get the Prime.

    Take care,
    Anand
    Reply
  • agt499 - Thursday, December 01, 2011 - link

    Alt-tab was one of many things that impressed with my OG transformer -you don't use the honeycomb task switcher because you just alt-tab with the keyboard!
    I have to say asus really get it on that: I don't know for sure if it's asus or google , but the others that warm by keyboard-loving heart are ctrl-t for a new tab in browser and ctrl-w to close a tab.
    Also re zooming, I can't speak for the prime, but the original will pinch-zoom with the touchpad.

    Thanks for the great review -got to find an excuse to upgrade now!
    (you're still right about an ultrabook but it feels like asus are so close...)
    Reply
  • twotwotwo - Friday, December 02, 2011 - link

    Ahaha -- I managed to use my Transformer all this time lamenting the lack of keyboard-based task switching but without actually trying Alt-Tab, which of course should be the first thing to try. Thank you, agt499. Reply
  • twotwotwo - Thursday, December 01, 2011 - link

    I have an original Transformer that I've used as my work machine a few days, and I also used a netbook as my only machine for six months. Transformer's very much a tablet and not a computer, because of Honeycomb. The bad task switching and other annoyances -- different text-editing shortcuts, lack of a full Docs app, lag editing paragraphs in the browser, etc. -- mean it's fine for the reading/consumption that folks do on tablets (and better for e-mail, chat, some writing or notetaking, and SSH if you do that) but, for me, it's worse than even a netbook at other stuff.

    If you're thinking of it for tablet-y (or mostly tablet-y) uses it's a slam dunk: it's a tablet, great screen, mobile OS, monster battery life even vs. netbooks.

    If you want a computer, you want a computer. Besides netbooks and ultrabooks, there's the Core i3 ULV x121e (and others like it soon, I hope) in the middle.
    Reply
  • joshv - Thursday, December 01, 2011 - link

    Why exactly don't we expect these sorts of machines to be running photoshop? Very complex versions of photoshop ran just fine on single core P6's with a 1024x768 monitor.

    Now we have four GHz+ cores, CPU speed really can't be much of an issue. Screen realestate might be, but that's manageable with alternate layouts.
    Reply
  • metafor - Thursday, December 01, 2011 - link

    I think the biggest limitation with programs like Photoshop on small form-factor devices -- including ultrabooks -- is the display resolution. Now granted, for a lot of simple photo editing, that won't matter -- and in fact, that's what Photoshop Touch is for -- but for more professional level content, the displays may just be too small and low-resolution to get the job done.

    But you're right, the processing power is there nowadays.
    Reply
  • anactoraaron - Thursday, December 01, 2011 - link

    I always assumed it was an x86 issue. Since there's no x86 support in these devices Adobe will not re-write/compile the software - kinda like how it took years to have a native x64 flash player (and not a x86 kinda running in an x64 browser).

    I would think it's simply a matter of laziness/unwillingness (profit margin?) on Adobe's part.
    Reply
  • metafor - Thursday, December 01, 2011 - link

    Photoshop Touch and a suite of other tools is coming to Android within a month or so. Adobe wants to grasp opportunities; but just porting a mouse-and-keyboard application to Android isn't the way to go about it. Reply
  • ctrlbrk - Thursday, December 01, 2011 - link

    Anand, thank you. I have been eyeing this tablet for a long time now.

    I want to know your impressions of how it feels in your hands, weight wise? For bedroom surfing, email, youtube, etc -- but not movie watching -- is the 10.1 too big and too heavy? Is it better to get something like the Galaxy Tab 8.9?
    Reply

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