NVIDIA Reveals 64-bit Denver CPU Core Details, Headed to New Tegra K1 Powered Devices Later This Year

Subject: Processors | August 12, 2014 - 01:06 AM |
Tagged: tegra k1, project denver, nvidia, Denver, ARMv8, arm, Android, 64-bit

During GTC 2014 NVIDIA launched the Tegra K1, a new mobile SoC that contains a powerful Kepler-based GPU. Initial processors (and the resultant design wins such as the Acer Chromebook 13 and Xiaomi Mi Pad) utilized four ARM Cortex-A15 cores for the CPU side of things, but later this year NVIDIA is deploying a variant of the Tegra K1 SoC that switches out the four A15 cores for two custom (NVIDIA developed) Denver CPU cores.

Today at the Hot Chips conference, NVIDIA revealed most of the juicy details on those new custom cores announced in January which will be used in devices later this year.

The custom 64-bit Denver CPU cores use a 7-way superscalar design and run a custom instruction set. Denver is a wide but in-order architecture that allows up to seven operations per clock cycle. NVIDIA is using a custom ISA and on-the-fly binary translation to convert ARMv8 instructions to microcode before execution. A software layer and 128MB cache enhance the Dynamic Code Optimization technology by allowing the processor to examine and optimize the ARM code, convert it to the custom instruction set, and further cache the converted microcode of frequently used applications in a cache (which can be bypassed for infrequently processed code). Using the wider execution engine and Dynamic Code Optimization (which is transparent to ARM developers and does not require updated applications), NVIDIA touts the dual Denver core Tegra K1 as being at least as powerful as the quad and octo-core packing competition.

Further, NVIDIA has claimed at at peak throughput (and in specific situations where application code and DCO can take full advantage of the 7-way execution engine) the Denver-based mobile SoC handily outpaces Intel’s Bay Trail, Apple’s A7 Cyclone, and Qualcomm’s Krait 400 CPU cores. In the results of a synthetic benchmark test provided to The Tech Report, the Denver cores were even challenging Intel’s Haswell-based Celeron 2955U processor. Keeping in mind that these are NVIDIA-provided numbers and likely the best results one can expect, Denver is still quite a bit more capable than existing cores. (Note that the Haswell chips would likely pull much farther ahead when presented with applications that cannot be easily executed in-order with limited instruction parallelism).

NVIDIA Denver CPU Core 64bit ARMv8 Tegra K1.png

NVIDIA is ratcheting up mobile CPU performance with its Denver cores, but it is also aiming for an efficient chip and has implemented several power saving tweaks. Beyond the decision to go with an in-order execution engine (with DCO hopefully mostly making up for that), the beefy Denver cores reportedly feature low latency power state transitions (e.g. between active and idle states), power gating, dynamic voltage, and dynamic clock scaling. The company claims that “Denver's performance will rival some mainstream PC-class CPUs at significantly reduced power consumption.” In real terms this should mean that the two Denver cores in place of the quad core A15 design in the Tegra K1 should not result in significantly lower battery life. The two K1 variants are said to be pin compatible such that OEMs and developers can easily bring upgraded models to market with the faster Denver cores.

NVIDIA Denver CPU cores in Tegra K1.png

For those curious, In the Tegra K1, the two Denver cores (clocked at up to 2.5GHz) share a 16-way L2 cache and each have 128KB instruction and 64KB data L1 caches to themselves. The 128MB Dynamic Code Optimization cache is held in system memory.

Denver is the first (custom) 64-bit ARM processor for Android (with Apple’s A7 being the first 64-bit smartphone chip), and NVIDIA is working on supporting the next generation Android OS known as Android L.

The dual Denver core Tegra K1 is coming later this year and I am excited to see how it performs. The current K1 chip already has a powerful fully CUDA compliant Kepler-based GPU which has enabled awesome projects such as computer vision and even prototype self-driving cars. With the new Kepler GPU and Denver CPU pairing, I’m looking forward to seeing how NVIDIA’s latest chip is put to work and the kinds of devices it enables.

Are you excited for the new Tegra K1 SoC with NVIDIA’s first fully custom cores?

Source: NVIDIA

Rumors point to Apple moving to ARM processors for future notebooks

Subject: Processors, Mobile | May 6, 2011 - 07:11 PM |
Tagged: project denver, nvidia, macbook, Intel, arm, apple

A very interesting story over at AppleInsider has put the rumor out there that Apple may choose to ditch the Intel/x86 architecture all together with some future upcoming notebooks.  Instead, Apple may choose to go the route of the ARM-based processor, likely similar to the A4 that Apple built for the iPhone and iPad.

What is holding back the move right now?  Well for one, the 64-bit versions of these processors aren't available yet and Apple's software infrastructure is definitely dependent on that.  By the end of 2012 or early in 2013 those ARM-based designs should be ready for the market and very little would stop Apple from making the move.  Again, this is if the rumors are correct.

applea4.png

Another obstacle is performance - even the best ARM CPUs on the market fall woefully behind the performance of Intel's current crop of Sandy Bridge processors or even their Core 2 Duo options.  

In addition to laptops, the report said that Apple would "presumably" be looking to move its desktop Macs to ARM architecture as well. It characterized the transition to Apple-made chips for its line of computers as a "done deal."

"Now you realize why Apple is desperately searching for fab capacity from Samsung, Global Foundries, and TSMC," the report said. "Intel doesn't know about this particular change of heart yet, which is why they are dropping all the hints about wanting Apple as a foundry customer. Once they realize Apple will be fabbing ARM chips at the expense of x86 parts, they may not be so eager to provide them wafers on advanced processes."

Even though Apple is already specing its own processors like the A4 there is the possibility that they could go with another ARM partner for higher performance designs.  NVIDIA's push into the ARM market with Project Denver could be a potential option as they are working very closely with ARM on those design and performance improvements.  Apple might just "borrow" those changes however at NVIDIA's expense and build its own option that would satisify its needs exactly without the dependence on third-parties.  

tegra2.JPG

Migrating the notebook (and maybe desktop markets) to ARM processors would allow the company to unify their operating system across the classic "computer" designs and the newer computer models like iPads and iPhones.  The idea of all of our computers turning into oversized iPhones doesn't sound appealing to me (nor I imagine, many of you) but with some changes in the interface it could become a workable option for many consumers. 

With even Microsoft planning for an ARM-based version of Windows, it seems that x86 dominance in the processor market is being threatened without a doubt.  

Source: AppleInsider