Bay Trail is based on Intel’s 22nm process technology with 3D tri-gate transistors and a new microarchitecture known as Silvermont. The Bay Trail-T platform, branded the Atom Z3000 series, is designed for tablets running Windows 8.1 and Android. It will replace the Atom Z2760 (Clover Trail) used in a handful of Windows 8 tablets and the Atom Z2560 (Clover Trail+) used in the Samsung Galaxy Tab 3, a 10-inch Android tablet.
Acer, Asus, Dell, Fujitsu, HP, Lenovo, LG and Toshiba are all developing Bay Trail-based tablets and the first of these will be available in time for the holidays at prices starting around $200. Intel says these tablets will have displays from 7 to 11.6 inches, measure 8mm thick and weigh 680 grams or less, and deliver up to 10 hours of battery life (and three days of standby time).
Bay Trail is actually a family of products that will also include versions for low-cost laptops, desktops and all-in-ones (more on those below) branded as Celeron and Pentium. And the underlying Silvermont microarchitecture will be used in other platforms including Merrifield for smartphones in 2014; the Atom C2000 (Avoton) for microservers and Rangeley for storage; and at least one unannounced chip most likely for set-top boxes and smart TVs.
Bay Trail Tablets
But the top priority is tablets. In a keynote on Tuesday morning, Hermann Eul, who heads up Intel’s Mobile and Communications Group, said that the Bay Trail platform will provide the “best mobile computing experience” with leading performance and outstanding battery life, Intel HD Graphics, and advanced imaging capabilities.
Some of the improvements come from the 22nm process technology, but Belli Kuttana, the chief architect of Intel’s low-power Atom cores, estimated that fully two-thirds of the improvements come from Silvermont (first disclosed back in May). It includes several microarchitectural enhancements that deliver better performance and longer battery life, and make access to memory faster and more efficient. The result, Kuttana said, is three times better peak performance or five times better power efficiency compared to the Saltwell core, which dates to Atom’s introduction in 2008.
The Silvermont core is packaged into modules, each of which contains two CPU cores, up to 1MB of shared L2 cache and a new interface that connects the clusters to the DRAM memory via a system agent. Processors based on Silvermont can have up to 8 CPU cores (four clusters). Even though Intel has abandoned multi-threading with Silvermont, the core is still yielding better performance on both single- and multi-threaded applications. Silvermont also includes several architectural changes borrowed from Core processors including new instructions, better virtualization support and increased security.
Kuttana also promised that Intel would be updating the Atom microarchitecture much more rapidly with 14nm Airmont in 2014 followed by a new 14nm microarchitecture in 2015. “It took us a while to refresh the Atom core microarchitecture, and that’s going to change,” he said. “We’ll be much more aggressive with our Atom microarchitectural improvements.” He later added that Atom doesn’t necessarily follow Core’s tick-tock model, suggesting that Intel will introduce microarchitectural changes more frequently.
The Bay Trail processor
In a separate technical session, Shreekant (“Ticky”) Thakkar, chief architect of Bay Trail-T, talked about how Silvermont is put together with other components to build the Atom Z3000 series SoC. The platform includes the Z3700 quad-cores for both Windows and Android tablets and the Z3600 series dual-cores, which will be for lower-cost Android tablets. The Z3000 includes four cores (two clusters), a total of 2MB of L2 cache, up to 4GB of memory, Intel HD Graphics, and advanced image and display processors. Bay Trail supports up to 4GB of low-power DDR3 memory, in comparison to 2GB of LP-DDRR2 for Clover Trail, and has up to twice the memory bandwidth at 17GBps (dual channels).
The first chips available are both quad-cores: the 1.5GHz Atom Z3770, which can burst to 2.4GHz, and the 1.3GHz Z3740, which can reach a maximum frequency of 1.9GHz. Both have the same Intel HD graphics—four execution units running at 311MHz with a top speed of 667MHz (slightly higher with low-voltage DDR3L memory). The SoC can shift power between the CPU and graphics cores and other components depending on the workload. Intel also plans to release a dual-core 1.3GHz Z3680, which can burst up 2.0GHz, with only a single memory channel (8.5GBps) for up to 1GB of memory. This limits the display resolution to 1280x800, and the chip is clearly targeted at low-cost Android tablets.
Clover Trail uses Imagination’s PowerVR graphics, so the shift to Intel HD Graphics is a big change. “The same technology you have on our Core platforms is now available on our tablet platform,” Thakkar said. In presentations, Intel described it as Gen 7 graphics—the same as Ivy Bridge Core processors, which also support DirectX 11 and OpenGL ES 3.0—but Bay Trail has fewer execution units and runs at slower speeds. In other sessions company executives said the performance was comparable to the Gen 6 graphics in Sandy Bridge. Either way it is a big boost. Bay Trail can support internal displays with resolutions up to 2,560x1,600 (though Windows 8 tops out at 2,560x1,440), drive external displays at up to 1920x1080 at 60 frames per second, and has hardware-accelerated video playback and H.264 encoding.
During IDF, Intel engineers showed lots of test results comparing the Z3770 to the current Atom Z2560, Qualcomm Snapdragon 800 and Nvidia Tegra 4. Not surprisingly, Bay Trail looks very competitive on these tests, though Thakkar admitted that Intel is still playing catch-up on 3D graphics. “In gaming we are significantly better, but still not the best,” he said. “But we are getting there and we’re still fine-tuning the drivers.” Several reviews sites have also posted early test results—including Anandtech, PCMag and Tech Report—all of which seem to confirm that Bay Trail is a serious competitor in terms of both performance and power.
Like previous Atom platforms, the current Bay Trail-T platform is 32-bit only, which makes sense given that version of Windows 8.1 with the Connected Standby features is currently 32-bit only, as is Android. In the first quarter of 2014, Intel plans to release a 64-bit version of Bay Trail-T; Microsoft is expected to deliver a 64-bit version of Windows 8.1 with Connected Standby around the same time. In his keynote, Doug Fisher, vice president and general manager of the Software and Services Group, said Intel would be adding 64-bit capabilities Android too.
The 64-bit Windows support, in particular, should be attractive to businesses. Organizations can use the same OS image for both Core-based laptops and Bay Trail tablets, and existing 32- and 64-bit applications will run fine on both platforms. In addition Intel has brought many of the security and management features in its Core processors over to Bay Trail-T for both Windows and Android tablets.
Bay Trail for PCs
One of the biggest surprises is that Bay Trail will also be widely used in low-priced laptops, desktops and all-in-ones. The line includes four Bay Trail-M mobile processors (Pentium N3510, Celeron N2910, N2810 and N2805) and three Bay Trail-D desktop chips, though so far Intel has released only the quad-core desktop versions: the 3770D (Pentium J2850) and 3740D (Celeron J1850). As with the tablet platform, there will also be a dual-core version, the Z3680D, branded the Celeron J1750.
While these are very similar to Bay Trail-T, there are some differences. Bay Trail-M/D processors have SATA 2.0 and PCI-Express interfaces, which are important in PCs but use too much power for tablets. Based on one of the presentations, it also looks like the Bay Trail-D processors have a single memory channel (10.6GBps) and support up to 2GB of low-voltage DDR3L, which would limit them to 1920x1280 displays, though this doesn’t seem to be the case with Bay Trail-M.
Bay Trail-M will be used in both low-end laptops and convertibles. Standard laptops will start at $200, touchscreen laptops will be $250 and up, and 2-in-1 devices such as the Transformer Book T100 will start at $350. Bay Trail-D is designed for three different types of products: entry-level all-in-ones and “portable” all-in-ones ranging; entry-level desktops; and, in an interesting wrinkle, Smart Displays running Android. Intel says that Bay Trail-D desktops will start at around $200. Bay Trail-D could also do especially well in emerging markets where the desktop market is larger and PC penetration is still relatively low.
The bottom line on Bay Trail
There’s no doubt that Bay Trail makes Intel more competitive in tablets. It closes the gap in terms of performance and power. Intel is now willing to compete at much lower prices. And the ability to run both Windows 8.1 and Android on the same platform--along with a host of business features--give Bay Trail real differentiation (eventually we may even see some low-cost convertibles that run Android as tablets and Windows 8.1 as laptops, which should be very attractive).
But it all comes down to great designs, and here the jury is still out. The Transformer Book T100 is a very nice 2-in-1, but it doesn’t seem like the sort of device that is going to really change the mobile landscape. We’ve yet to hear about a Bay Trail-based Samsung Galaxy or Google Nexus tablet, and of course there’s no Intel inside the iPad. Intel finally has a real platform; now it just needs some great gadgets to go with it.