Subject: Mobile | May 22, 2013 - 07:46 PM | Tim Verry
Tagged: Tegra 4i, software defined radio, SoC, nvidia, i500, 4g lte
NVIDIA's Tegra 4i System on a Chip includes a software defined radio that works as a LTE modem. This i500 LTE modem uses general purpose deep execution processors (DXP) and is as much as 40% smaller than a hardware LTE modem according to the company.
At Mobile World Congress earlier this year, the modem was able to reach 100Mbps throughput. After a recent software update, the Tegra 4i SoC in NVIDIA's Pheonix reference platform achieved 150Mbps throughput in a demo at CITA 2013 in Los Angeles this week.
The reference phone was connected to a test network during the demo rather than a live cellular network. The cellular network test equiptment showed the Pheonix platform was connected at the full 150Mbps link speed. In addition to this, NVIDIA showed the Tegra 4i-powered Pheonix phone connected to a live AT&T LTE network streaming video and making voice calls.
The interesting bit about the i500 modem in the Tegra 4i is its software defined nature. NVIDIA was able to upgrade the modem's capabilites through software rather than needing to redesign the hardware. This would be a big plus to consumers as they would be able to take advantage of the faster network speeds as they become available without needing to replace their phones. NVIDIA did note that in addition to the LTE Cat 4 support, the i500 is also backwards compatible with LTE Cat 3, 3G, and 2G networks. I'm interested to see what the power consumption of thei500 is like compared to LTE modems implemented in specialized hardware. The i500 is smaller and more flexible, but SDR can use more power due to its general purpose hardware units.
Read more about NVIDIA's Tegra 4i SoC at PC Perspective!
Subject: Graphics Cards | February 25, 2013 - 08:01 PM | Josh Walrath
Tagged: nvidia, tegra, tegra 4, Tegra 4i, pixel, vertex, PowerVR, mali, adreno, geforce
When Tegra 4 was introduced at CES there was precious little information about the setup of the integrated GPU. We all knew that it would be a much more powerful GPU, but we were not entirely sure how it was set up. Now NVIDIA has finally released a slew of whitepapers that deal with not only the GPU portion of Tegra 4, but also some of the low level features of the Cortex A15 processor. For this little number I am just going over the graphics portion.
This robust looking fellow is the Tegra 4. Note the four pixel "pipelines" that can output 4 pixels per clock.
The graphics units on the Tegra 4 and Tegra 4i are identical in overall architecture, just that the 4i has fewer units and they are arranged slightly differently. Tegra 4 is comprised of 72 units, 48 of which are pixel shaders. These pixel shaders are VLIW based VEC4 units. The other 24 units are vertex shaders. The Tegra 4i is comprised of 60 units, 48 of which are pixel shaders and 12 are vertex shaders. We knew at CES that it was not a unified shader design, but we were still unsure of the overall makeup of the part. There are some very good reasons why NVIDIA went this route, as we will soon explore.
If NVIDIA were to transition to unified shaders, it would increase the overall complexity and power consumption of the part. Each shader unit would have to be able to handle both vertex and pixel workloads, which means more transistors are needed to handle it. Simpler shaders focused on either pixel or vertex operations are more efficient at what they do, both in terms of transistors used and power consumption. This is the same train of thought when using fixed function units vs. fully programmable. Yes, the programmability will give more flexibility, but the fixed function unit is again smaller, faster, and more efficient at its workload.
On the other hand here we have the Tegra 4i, which gives up half the pixel pipelines and vertex shaders, but keeps all 48 pixel shaders.
If there was one surprise here, it would be that the part is not completely OpenGL ES 3.0 compliant. It is lacking in one major function that is required for certification. This particular part cannot render at FP32 levels. It has been quite a few years since we have heard of anything not being able to do FP32 in the PC market, but it is quite common to not support it in the power and transistor conscious mobile market. NVIDIA decided to go with a FP 20 partial precision setup. They claim that for all intents and purposes, it will not be noticeable to the human eye. Colors will still be rendered properly and artifacts will be few and far between. Remember back in the day when NVIDIA supported FP16 and FP32 while they chastised ATI for choosing FP24 with the Radeon 9700 Pro? Times have changed a bit. Going with FP20 is again a power and transistor saving decision. It still supports DX9.3 and OpenGL ES 2.0, but it is not fully OpenGL ES 3.0 compliant. This is not to say that it does not support any 3.0 features. It in fact does support quite a bit of the functionality required by 3.0, but it is still not fully compliant.
This will be an interesting decision to watch over the next few years. The latest Mali 600 series, PowerVR 6 series, and Adreno 300 series solutions all support OpenGL ES 3.0. Tegra 4 is the odd man out. While most developers have no plans to go to 3.0 anytime in the near future, it will eventually be implemented in software. When that point comes, then the Tegra 4 based devices will be left a bit behind. By then NVIDIA will have a fully compliant solution, but that is little comfort for those buying phones and tablets in the near future that will be saddled with non-compliance once applications hit.
The list of OpenGL ES 3.0 features that are actually present in Tegra 4, but the lack of FP32 relegates it to 2.0 compliant status.
The core speed is increased to 672 MHz, well up from the 520 MHz in Tegra 3 (8 pixel and 4 vertex shaders). The GPU can output four pixels per clock, double that of Tegra 3. Once we consider the extra clock speed and pixel pipelines, the Tegra 4 increases pixel fillrate by 2.6x. Pixel and vertex shading will get a huge boost in performance due to the dramatic increase of units and clockspeed. Overall this is a very significant improvement over the previous generation of parts.
The Tegra 4 can output to a 4K display natively, and that is not the only new feature for this part. Here is a quick list:
2x/4x Multisample Antialiasing (MSAA)
24-bit Z (versus 20-bit Z in the Tegra 3 processor) and 8-bit Stencil
4K x 4K texture size incl. Non-Power of Two textures (versus 2K x 2K in the Tegra 3 processor) – for higher quality textures, and easier to port full resolution textures from console and PC games to Tegra 4 processor. Good for high resolution displays.
16:1 Depth (Z) Compression and 4:1 Color Compression (versus none in Tegra 3 processor) – this is lossless compression and is useful for reducing bandwidth to/from the frame buffer, and especially effective in antialiasing processing when processing multiple samples per pixel
Percentage Closer Filtering for Shadow Texture Mapping and Soft Shadows
Texture border color eliminate coarse MIP-level bleeding
sRGB for Texture Filtering, Render Surfaces and MSAA down-filter
1 - CSAA is no longer supported in Tegra 4 processors
This is a big generational jump, and now we only have to see how it performs against the other top end parts from Qualcomm, Samsung, and others utilizing IP from Imagination and ARM.
Subject: General Tech | February 21, 2013 - 02:58 AM | Ken Addison
Tagged: titan, Tegra 4i, tegra 4, ssd, ps4, podcast, nvidia, Intel
PC Perspective Podcast #239 - 02/21/2013
Join us this week as we discuss NVIDIA GTX TITAN, PlayStation 4 Hardware, SSD Endurance and more!
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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.