NVIDIA Releases Tegra 4i: I Shall Name It... Mini-Me!
Subject: Processors | February 20, 2013 - 09:35 PM | Josh Walrath
Tagged: Tegra 4i, tegra 4, tegra 3, Tegra 2, tegra, phoenix, nvidia, icera, i500
The NVIDIA Tegra 4 and Shield project were announced at this year’s CES, but there were other products in the pipeline that were just not quite ready to see the light of day at that time. While Tegra 4 is an impressive looking part for mobile applications, it is not entirely appropriate for the majority of smart phones out there. Sure, the nebulous “Superphone” category will utilize Tegra 4, but that is not a large part of the smartphone market. The two basic issues with Tegra 4 is that it pulls a bit more power at the rated clockspeeds than some manufacturers like, and it does not contain a built-in modem for communication needs.
The die shot of the Tegra 4i. A lot going on in this little guy.
NVIDIA bought up UK modem designer Icera to help create true all-in-one SOCs. Icera has a unique method with building their modems that they say is not only more flexible than what others are offering, but also much more powerful. These modems skip a lot of fixed function units that most modems are made of and rely on high speed general purpose compute units and an interesting software stack to create smaller modems with greater flexibility when it comes to wireless standards. At CES NVIDIA showed off the first product of this acquisition, the i500. This is a standalone chip and is set to be offered with the Tegra 4 SOC.
Yesterday NVIDIA introduced the Tegra 4i, formerly codenamed “Grey”. This is a combined Tegra SOC with the Icera i500 modem. This is not exactly what we were expecting, but the results are actually quite exciting. Before I get too out of hand about the possibilities of the chip, I must make one thing perfectly clear. The chip itself will not be available until Q4 2013. It will be released in limited products with greater availability in Q1 2014. While NVIDIA is announcing this chip, end users will not get to use it until much later this year. I believe this issue is not so much that NVIDIA cannot produce the chips, but rather the design cycles of new and complex cell phones do not allow for rapid product development.
Tegra 4i really should not be confused for the slightly earlier Tegra 4. The 4i actually uses the 4th revision of the Cortex A9 processor rather than the Cortex A15 in the Tegra 4. The A9 has been a mainstay of modern cell phone processors for some years now and offers a great deal of performance when considering die size and power consumption. The 4th revision improves IPC of the A9 in a variety of ways (memory management, prefetch, buffers, etc.), so it will perform better than previous Cortex A9 solutions. Performance will not approach that provided by the much larger and complex A15 cores, but it is a nice little boost from what we have previously seen.
The Tegra 4 features a 72 core GPU (though NVIDIA has still declined to detail the specifics of their new mobile graphics technology- these ain’t Kepler though), while the 4i features a nearly identical unit featuring 60 cores. There is no word so far as to what speed these will be running at or how performance really compares to the latest graphics products from ARM, Imagination, or Qualcomm.
The chip is made on TSMC’s 28 nm HPM process and features core speeds up to 2.3 GHz. We again have no information on if that will be all four cores at that speed or turbo functionality with one core. The design adopts the previous 4+1 core setup with four high speed cores and one power saving core. Considering how small each core is (Cortex A9 or A15) it is not a waste of silicon as compared to the potential power savings. The HPM process is the high power version rather than the LPM (low power) used for Tegra 4. My guess here is that the A9 cores are not going to pull all that much power anyway due to their simpler design as compared to A15. Hitting 2.3 GHz is also a factor in the process decision. Also consider that +1 core that is fabricated slightly differently than the other four to allow for slower transistor switching speed with much lower leakage.
The die size looks to be in the 60 to 65 mm squared range. This is not a whole lot larger than the original Tegra 2 which was around 50 mm squared. Consider that the Tegra 4i has three more cores, a larger and more able GPU portion, and the integrated Icera i500 modem. The modem is a full Cat 3 LTE capable unit (100 mbps), so bandwidth should not be an issue for this phone. The chip has all of the features of the larger Tegra 4, such as the Computational Photography Architecture, Image Signal Processor, video engine, and the “optimized memory interface”. All of those neat things that NVIDIA showed off at CES will be included. The only other major feature that is not present is the ability to output 3200x2000 resolutions. This particular chip is limited to 1920x1200. Not a horrific tradeoff considering this will be a smartphone SOC with a max of 1080P resolution for the near future.
We expect to see Tegra 4 out in late Q2 in some devices, but not a lot. While Tegra 4 is certainly impressive, I would argue that Tegra 4i is the more marketable product with a larger chance of success. If it were available today, I would expect its market impact to be similar to what we saw with the original 28nm Krait SOCs from Qualcomm last year. There is simply a lot of good technology in this core. It is small, it has a built-in modem, and performance per mm squared looks to be pretty tremendous. Power consumption will be appropriate for handhelds, and perhaps might turn out to be better than most current solutions built on 28 nm and 32 nm processes.
NVIDIA also developed the Phoenix Reference Phone which features the Tegra 4i. This is a rather robust looking unit with a 5” screen and 1080P resolution. It has front and rear facing cameras, USB and HDMI ports, and is only 8 mm thin. Just as with the original Tegra 3 it features the DirectTouch functionality which uses the +1 core to handle all touch inputs. This makes it more accurate and sensitive as compared to other solutions on the market.
Overall I am impressed with this product. It is a very nice balance of performance, features, and power consumption. As mentioned before, it will not be out until Q4 2013. This will obviously give the competition some time to hone their own products and perhaps release something that will not only compete well with Tegra 4i in its price range, but exceed it in most ways. I am not entirely certain of this, but it is a potential danger. The potential is low though, as the design cycles for complex and feature packed cell phones are longer than 6 to 7 months. While NVIDIA has had some success in the SOC market, they have not had a true homerun yet. Tegra 2 and Tegra 3 had their fair share of design wins, but did not ship in numbers that came anywhere approaching Qualcomm or Samsung. Perhaps Tegra 4i will be that breakthrough part for NVIDIA? Hard to say, but when we consider how aggressive this company is, how deep their developer relations, and how feature packed these products seem to be, then I think that NVIDIA will continue to gain traction and marketshare in the SOC market.