Inside Snapdragon is a Scorpion

Several years ago Qualcomm assembled an architecture team in the Research Triangle Park in NC, coincidentally around 30 minutes from where I live. One of their tasks was to design a high performance CPU core around the ARMv7 instruction set. They called it Scorpion.

While the Scorpion core is normally referred to as a Cortex A8, Qualcomm views it as more of a Cortex A9 competitor. The truth, as always, lies somewhere in between. Like the Cortex A8, Scorpion is a dual-issue in-order microprocessor architecture. As I mentioned in my iPhone 3GS article, you can think of it as a modern day Pentium processor (but not an Atom).

Qualcomm claims the ability to do some things out of order, but by and large the pipeline is in order which ultimately keeps it out of the A9 classification.

Qualcomm hasn't shared much about the base architecture other than to say that it's definitely not based on the Cortex A8. It might have a deeper pipeline than the Cortex A8 to help it reach higher clock speeds. Unlike the ~600MHz target the A8 will hit at 65nm, Qualcomm's Scorpion will run at 1GHz at 65nm.

Scorpion also implements the NEON extensions to the ARMv7 ISA, although Qualcomm's implementation is a higher throughput version of what the Cortex A8 offers. It's my understanding that NEON isn't very widespread in usage today, so I'm not sure that Qualcomm's advantage here matters just yet.

Cache sizes are unknown but I'd expect that they're competitive with what we've seen from competing Cortex A8 implementations. Ultimately everyone is bound by die size and power consumption at 65nm.

Qualcomm integrates the Scorpion core in its Snapdragon SoC. The version of Snapdragon in the Nexus One is the QSD8250. This SoC includes a 1GHz Scorpion core and an integrated 3G modem. The QSD8650 will be used in the Verizon version with support for EVDO and CDMA 2000.

Qualcomm's integrated modem is a very different approach from what we've seen from companies like NVIDIA, Apple/Samsung and TI. Those companies rely on an external modem solution to reduce time to market. Qualcomm's response is to instead offer an SoC that integrates support for all major wireless standards. The QSD8250 used in AT&T's supports GSM, GPRS, EDGE and HPSA networks.  The QSD8650 supports CDMA2000 1X, 1xEV-DO Rel 0/A/B, GSM, GPRS, EDGE and HSPA wireless networks.

When I spoke with Qualcomm one message it stressed was how calculated the timing of Snapdragon was. It's not by accident that all of the major Android phones being announced today use Snapdragon, it's because of very careful timing and planning that Qualcom was able to hit this bulge in the market. Most SoC makers would cite time to market as a reason for not integrating a modem into an application processor, it's clear that Qualcomm faced that challenge and took timing very seriously with Snap Dragon.

The CPU side of the Snapdragon SoC is fast. Faster than what's in the iPhone 3GS, Palm Pre and Motrola Droid. Unfortunately there are other issues. Qualcomm scaled up processing speed but didn't increase memory bandwidth. The Snapdragon still has a 32-bit LPDDR1 interface, giving it the same memory bandwidth as its competitors despite boasting a much higher clock speed.

The even bigger problem with Snapdragon is its use of the Adreno 200, a dated and slow GPU Qualcomm acquired from ATI a couple of years ago. Luckily for Qualcomm, intensive 3D gaming hasn't really taken off on smartphones just yet but here Snapdragon is at a disadvantage to the Samsung and TI SoCs that use Imagination Tech's PowerVR SGX.

So the Nexus One has better CPU performance, identical memory bandwidth and worse GPU performance compared to the iPhone 3GS. Nothing is ever easy in this world.

Later this year Qualcomm will introduce its 45nm Snapdragon SoCs. These will range from being simple clock bumps of the 8650 in the Nexus One with LPDDR2 support, to full fledged dual-core versions with a much higher performance 3D core. Qualcomm also confirmed its intentions to move to an out-of-order architecture at some point in the future. I'd expect to hear more about that next year.

Enter the Snapdragon The Display, My Love, the Display
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  • Johnmcl7 - Sunday, April 04, 2010 - link

    Very much agreed, I thought far too much time was wasted on Iphone references which given the Iphone generally does everything worse I really couldn't care less about it. Most noticeably multitasking was only given a brief mention despite being being detailed extensively for the Palm Pre reviews.

    I didn't understand the complaint about the notifications either, to me as a non-Android user the system makes perfect sense - it seems entirely logical to have icons for each notification which when tapped show a list with text on each one.

    John
    Reply
  • jamawass - Saturday, April 03, 2010 - link

    Great review Anand. do you think the speech recognition worked well enough to be a complete subsitute for typed entry? I've been averse to touchscreen only devices (gave iphone to my wife) because I hate typing on them. Also did you try gesture search which has a highly publicized feature not too long ago?

    I'm currently using a treo pro windows mobile and even with all it's lack of polish it does feel like I am carrying a portable computer with me. I was hoping Windows7 series would enhance this but it appears as if MS is going to take the Apple approach in this regard. Looks like Android has picked up the windows mobile torch and literally flown to the stars with it.
    Reply
  • Sidharthmodi - Saturday, April 03, 2010 - link

    I liked the Depth in this Product Review. Thanks Anand. Reply
  • has407 - Saturday, April 03, 2010 - link

    Appreciate the depth and that it's based on extended use. Using the 3GS for comparison is spot-on (everything is relative). Thanks again. Reply
  • Chloiber - Saturday, April 03, 2010 - link

    Can we expect a review on the HTC Desire or Evo 4G?

    I know the specs are really quite the same (especially on the Desire) but HTC Sense UI gives the whole thing really a different touch and, according to first reviews, a much better usability.
    Reply
  • Anand Lal Shimpi - Saturday, April 03, 2010 - link

    We've been trying to get in touch with HTC to get review samples of both of those products. So far we haven't received any response but we won't stop trying :) Worst case, we'll just buy an EVO 4G when it comes out.

    Feel free to write HTC to provide some encouragement if you'd like :)

    Take care,
    Anand
    Reply
  • Chloiber - Sunday, April 04, 2010 - link

    Well, I'm waiting for my desire too :P

    Evo 4G will probably take even longer....to test Sense UI one can use the HTC Legend, Desire or Evo 4G - shouldn't make any real difference.

    Anyway, I'm looking forward to it :)
    Reply
  • relativityboy - Saturday, April 03, 2010 - link

    If you already have an Android powered phone you can find the Sense UI online, and run it with the appropriate Rom and tools. I just saw it running on a G1 today. It was pretty fast. :) Reply
  • relativityboy - Saturday, April 03, 2010 - link

    A very lengthy and thorough review of the bits, but I didn't come away with a solid understanding of how the device fits together as a user experience...the review feels, disjointed.

    The keyboard is narrow, how does that fit with the voice transcription?

    Sometimes scrolling in the 'app drawer' is slow, but what else was going on in the background? Were you pulling data, listening to music, what else was going on in the phone? The device/os is a true multi-threaded environment for applications. I didn't notice any emphasis there (a major win over iPhone).

    Did you try doing any benchmarking? Use 'Task Killer' or 'Setcpu'?

    Android is OPEN, unlike apple's mobile products.
    You can install apps that aren't in the app store.
    Memory is super-upgradeable (when was the last time a 4Gb or 8Gb iPhone could be upgraded to 32Gb for the price of a micro-sd chip?)

    The comment "It's Mac vs PC all over again" I think is totally missing representing what's going on here. Yet you hit the nail on the head later when you said Apple sees it as a device that's peripheral to laptops/pcs while Google is aiming for what it could be. Apple had a great idea, the iPhone. Google had a great idea a mobile environment/platform to allow lots of people to have great ideas. Google wants to let the world do the creating. The Nexus One as a device is a punctuation mark in a much larger story that includes the G1, Devour, HTC Evo, Droid, and others. Software development kits are available for-free for just about every platform you can shake a stick ate. Google is harnessing the creative powers of everyone who wants to get in on the game... The iPhone is just, well, Apple's 'one thing'.

    A very respected developer friend of mine once said, "In a contest between your software/idea and the real world, the real world always wins." Google knows this. Apple doesn't.

    I'm definitely an Android person, both by UI preference and ideology, but I don't feel like you've really tried, or given yourself enough time to 'get' what this platform is about.
    Reply
  • jasperjones - Saturday, April 03, 2010 - link

    Agree that Android's openness is of huge importance. On an iPhone, you can't even install an app that features a woman in bikini, Apple won't allow it. In this context, I always have to think of Tim Bray's statement that

    "The iPhone vision of the mobile internet’s future omits controversy, sex, and freedom, but includes strict limits on who can know what and who can say what. It’s a sterile Disneyfied walled garden surrounded by sharp-toothed lawyers."
    Reply

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