A couple of weeks ago at MWC, Qualcomm announced its Snapdragon 801 which was positioned as a speed bump for the next wave of flagship smartphones. Qualcomm touted a 2.5GHz CPU frequency (up from 2.3GHz with Snapdragon 800), as well as increased GPU, ISP and memory interface speeds. Samsung announced immediate support for the new Snapdragon 801 with the Galaxy S 5, as did Sony with the Xperia Z2. Unfortunately this is where confusion set in. The Galaxy S 5 was advertised as a Snapdragon 801 with a 2.5GHz CPU clock, while the Xperia Z2 claimed the same Snapdragon 801 branding but with a 2.3GHz CPU clock - the same frequency as a Snapdragon 800. If it's not CPU frequency that separates a Snapdragon 800 from an 801, what does? The answer, as it turns out, is a little more complex. The table below should help explain it all:

Snapdragon 800/801 Breakdown
  SoC Version Model Max CPU Frequency Max GPU Frequency ISP eMMC DSDA Memory IF
MSM8974VV v2 S800 2.2GHz 450MHz 320MHz 4.5 N 800MHz
MSM8974AA v2 S800 2.3GHz 450MHz 320MHz 4.5 N 800MHz
MSM8974AB v2 S800 2.3GHz 550MHz 320MHz 4.5 N 933MHz
MSM8974AA v3 S801 2.3GHz 450MHz 320MHz 5.0 Y 800MHz
MSM8974AB v3 S801 2.3GHz 578MHz 465MHz 5.0 Y 933MHz
MSM8974AC v3 S801 2.5GHz 578MHz 465MHz 5.0 Y 933MHz

The Snapdragon 800 brand applies to an internal Qualcomm model number of MSM8974. The MSM8974 has four Krait 400 CPU cores, an Adreno 330 GPU, dual-ISP, 64-bit wide memory interface and a 9x25 Cat 4 LTE modem. It turns out there are two different silicon revisions of this SoC: version 2 and 3. The Snapdragon 800 v2 silicon was made available in three different flavors: VV, AA and AB. The difference between all three MSM8974 v2 variants was CPU and GPU frequency. This isn't an unusual practice at all as there's bound to be a distribution of operating frequencies for any design. Better bins end up as higher clocked parts, while others get tested and pass at lower frequencies. OEMs can pay more for the faster bins if they want.

In the case of v2 silicon, you could end up with silicon that ran its CPU cores up to 2.2GHz or 2.3GHz. Only the AB variant saw its max GPU frequency climb to 550MHz. The rest of the specs remain identical between all v2 silicon (-AB does get access to faster DRAM). Note that I'm using the marketing frequencies here for CPUs and not the actual frequencies. For whatever reason the OEMs choose to round up to the nearest 100MHz when quoting CPU speeds (2.2GHz is actually 2.15GHz, 2.3GHz is actually 2.26GHz and 2.5GHz is actually 2.45GHz). That's a battle for another day.

Over time it's possible to squeeze more out of a given process and that's exactly what Qualcomm did with MSM8974 v3. This newer silicon revision used improvements on the process side (process push of 28nm HPm) to push frequencies even higher. The options are now 2.3GHz and 2.5GHz on the CPU side. Just like with v2, v3 silicon offers three different variants. Unlike the situation with v2, v3 sees increases in CPU, GPU and ISP operating frequencies depending on which bin an OEM orders. Note that the increases in ISP frequency are substantial. If my math is correct, the Snapdragon 801 should be able to push almost as many pixels through its ISP as the forthcoming 805.

The other major difference is that v3 silicon enables support for eMMC 5.0.

In short, there are two different versions of MSM8974 silicon. Version 3 adds eMMC 5.0 support and hardware dual-sim, dual-active (DS-DA). All variants of v3 silicon can carry the Snapdragon 801 branding, while all v2 variants are Snapdragon 800s.

Putting it in Perspective

What does all of this mean? Let's first talk about the non-frequency related benefits of MSM8974 v3. eMMC 5.0 adds some new features as well as increases the maximum interface speed from 200MB/s in eMMC 4.5 to 400MB/s. As high end smartphones and tablets start using faster internal storage, having eMMC 5.0 support will be necessary to enable faster transfer speeds. SanDisk's recently announced iNAND Extreme update promises 300MB/s sequential read performance for 32GB+ devices. On a smartphone equipped with USB 3 that means you could feasibly copy large movies or files off of your smartphone at up to 300MB/s. Without eMMC 5.0 support you'd be limited to somewhere south of 200MB/s.

DSDA support matters to specific regions, and for those areas the benefit is obvious.

Supporting faster LPDDR3 means more available memory bandwidth for all of the big consumers on the SoC. I'd expect improvements in high end 3D gaming performance, and potentially certain camera/imaging workloads. Remember that all parts of the SoC have to share that tiny interface to main memory, so more memory bandwidth definitely doesn't hurt.

On the frequency side, the gains are pretty easy to understand. The higher peak CPU speed will translate into faster web page and application loads. Higher GPU frequency will allow for smoother frame rates in 3D games, and the faster ISP frequency can enable quicker processing of camera sensor output. You can also look at the benefits of these things from the perspective of lowering power consumption. Tasks can now complete in less time, allowing these individual IP blocks to quickly move down to lower power states and increase battery life.

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  • En1gma - Tuesday, March 11, 2014 - link

    btw, where MSM8974 v1?
  • jerrylzy - Tuesday, March 11, 2014 - link

    V1's max frequency is 2GHz. I don't see any device coming with a 2.0G s800.
  • jerrylzy - Tuesday, March 11, 2014 - link

    Sorry 8974V1's max frequency is 1.7G.
  • phoenix_rizzen - Tuesday, March 11, 2014 - link

    Now, if only a phone manufacturer would take the time to optimise the hardware around the SoC.

    Keep the screen resolution at 1080p (or maybe something a little wider like 16:10 ratio). Keep the size under 5". Make it a mm or two thicker. Make the battery a little bigger.

    Or, stick this SoC into a 4", 720p setup and watch it scream!

    And, add a friggin' hardware keyboard! I want to be able to use my pocket computer like a computer again! And not just as a video watching machine.

    Then tweak the software and drivers to match.

    IOW, do to a 1080p phone what Motorola did to the X. There's no reason to push resolution beyond 1080p or screen sizes beyond 5", thus taxing these SoCs near their limits.
  • TenshiNo - Tuesday, March 11, 2014 - link

    Finally, somebody speaking sense in comments. All these people demanding 2K and 4K screens on their cell phones were beginning to drive me nuts! ;)
  • Mondozai - Monday, March 17, 2014 - link

    His comment makes zero sense. Optimise "the hardware around the SoC"?
    Then he mentions getting the phone bulkier and thicker. Hardware keyboard? Like a stunted netbook?

    Pure idiocy.
  • crazysurfanz - Tuesday, March 11, 2014 - link

    what I want to know is how you know which SOC a phone is going to come with... checking something like gsmarena.com or indeed reviews here on AT I guess.... but what's to stop a company from advertising a device with a Snapdragon 801 at 2.3ghz CPU freq and shipping it with either of the variants which could result in you getting a lower GPU freq than expected? (i.e. review models come out with the higher freq. gpu and then 3 months after release they quietly ship to the slower/cheaper variant without telling anyone).
  • TenshiNo - Tuesday, March 11, 2014 - link

    I guess the hope is that somebody, somewhere would notice. I think to call what would likely happen after that a "PR nightmare" would be putting it mildly.
  • Systems Analyst - Friday, March 14, 2014 - link

    You have to consider the big picture (sorry). ARM are aiming for a single standard across mobile phones, tablets, all-in-ones, STBs and DTVs. This will enable the delivery of a single standard of content, presumably 4k, to all devices. This is all mapped out years in advance. It is coming.
  • paul_59 - Tuesday, March 25, 2014 - link

    Even though 4K would be pointless on a phone with screen size of between five and six inches ?

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