Introduction to Tegra series
Tegra series is a system-on-chip developed by NVIDIA. Unlike Tegra 1, which is based on ARM11 design (slow!), NVIDIA skipped ARM Cortex A8 design (pretty fast!), and went straight to Cortex A9 design(very fast!). Cortex A9 is expected to significantly outperform Cortext A8 based processors but currently no benchmark results exist to prove this yet (well, almost - read further). Currently no smartphones on the market are using Cortex A9 based processors. Future Cortex A9 based processors include 3rd generation Qualcomm processors, Samsung's Orion and Texas Instrument's OMAP 4 platform.
Here are the phones you will find today that uses respective ARM designs:
- ARM 11: iPhone 3, HTC G1, Magic, Hero, etc.
- ARM Cortex A8: iPhone 3GS, iPhone 4, Nexus One, Motorola Droid, Droid X, Droid 2, Samsung Galaxy S, HTC Evo, HTC Desire HD, etc.
- ARM Cortex A9: None yet.
Tegra 2's GPU core is NVIDIA's own design. It is essentially the same design as the one found in Tegra 1, but faster. NVIDIA claims about 2-3x the performance improvement. I believe it since the bandwidth alone between the processor and the memory increased 2x.
They also claim far less power consumption when Tegra 2 chip is decoding music and video compare to Qualcomm's Snapdragon processors. If this is true, Tegra 2 based phones will last significantly longer when listening music and watching YouTube video.
So what makes Tegra 2 CPU core go fast? This is really asking a question of what makes ARM Cortex A9 fast. ARM has implemented out-of-order execution on its dual-issue pipeline. It also features a shorter pipeline which helps complete instructions faster. Cortex A9 is expected to feature significantly better IPC (instructions per clock) than Cortex A8. In other words, 1GHz Cortex A9 core will perform significantly better than 1GHz Cortex A8 core (about 25% improvement!). And on top, Cortex A9 is known to clock well - up to 2GHz. However, whether NVIDIA can scale other components in Tegra 2 will be a separate question all together.
So in short, 1GHz dual-core Cortex A9 will destroy any 1GHz single-core Cortex A8 based processors. Also, NVIDIA's design can be extended to quad-core packaging. Eventually, we may see a quad-core Tegra 2 processors if there is a market for it.
What we are seeing here, is essentially a repeat of the evolution of the desktop processors in a smaller, more efficient package.
Devices using Tegra 2
Some vendors are producing devices based on Tegra 2 already. One of the early adopters is Toshiba. Toshiba AC100 is a netbook that uses Tegra 2 processor.
Check out the Quadrant benchmark score for AC100:
Not impressed? Based on this observation, Samsung's Galaxy S (which is based on ARM Cortex A8 design) outperforms AC100!
I think the reasons are as follows:
- Quadrant measures overall system performance, including GPU performance. Galaxy S features a great performing GPU for current generation - Hummingbird's PowerVR SGX540. No phones can perform at this level as of today. Only HTC G2/Desire Z/Desire HD are closing the gap using their second generation Snapdragon processors. Perhaps the GPU in Tegra 2 isn't as good as PowerVR SGX540. Although 2-3x faster than GPU found in Tegra 1, Tegra 1 is not a speed demon by today's standard.
- Quadrant isn't dual-core ready - I doubt this application utilizes two cores in Tegra 2. I would be very surprised if ANY smartphone applications are multi-core aware yet. This will change quickly however as more dual-core hardware arrives to the scene. Once Quadrant is updated to handle dual-core processors, I believe the score will improve significantly.
- AC100 ran using a netbook screen resolution which is higher than today's smartphones. It is more than likely that this would have impacted the 2D/3D results.
Motorola, LG and Samsung have announced that they will produce smartphones based on Tegra 2 processors in the near future.
UPDATED (Oct 4, 2010): Verizon/Motorola have announced a new model called Droid T2 to be released by Christmas this year. Notice that they claim this will be a dual-core phone, and the word "T2" (as in Tegra 2).
What do I think of Tegra 2 processor?
I like it. It IS based on the latest generation ARM Cortex A9 based design. Tegra 2 is the first SoC to come to the market for smartphones with this state of the art design. With the combination of IPC improvement and dual-core design, it will seriously run any typical smartphone applications that are being used today (and perhaps in the near future) very well.
Its GPU appears to be a bit weak based on the first impression. Samsung's Hummingbird GPU might still have an edge here. So if 3D games is all you do on your phones, Galaxy S may work out better for you.
So until other Cortex A9 based processors arrive to the scene by Samsung, Qualcomm and Texas Instrument, this might have the fastest solution.
NVIDIA has intentionally left out the modem component from Tegra 2 SoC. I don't blame them for not tackling the mess we are currently in with the presence of GSM/CDMA/HSPA/LTE using different bands depending on where you live. But it does mean individual phone manufacturers will have to add their own modems instead, which is a overhead both in time and money. Will LG and Samsung deliver competitive phones using Tegra 2 chip sets? We will find out soon.
Specification for Tegra 2 series can be found here:
Some interesting points from the specification:
- 1080p H.264/VC-1/MPEG-4 Video Decode
- 1080p H.264 Video Encode
- True dual-display support
- 1080p (1920x1080) HDMI 1.3 capable
- WSXGA+ (1680x1050) LCD capable
- NTSC/PAL TV output
UPDATED (Sep 20, 2010): Apparently there's some question on Tegra 2's usefulness due to its inability to handle the High Profile 1080p H.264 encoded files. And indeed this appears to be true based on the recent news on Boxee switching from Tegra 2 to Intel's Atom CE4100. I am also curious to see what NVIDIA has to say about this. This will probably not affect smartphones much, but on tablets and netbooks, it may become an issue for some users.