Cavium plans four families of Thunder chips, targeting storage, networking, and security systems in addition to servers. Each family will use a different set of I/O and accelerator blocks from Cavium's existing silicon library.
The company plans to roll out high-end versions from all four groups initially. It aims to round out the portfolios three to six months later with 8 to 16 core versions.
The initial server SoCs will support DDR4 and integrate PCI Express Gen 3 x4 and x8 links. The server SoCs likely will pack just one or two 10G Ethernet controllers initially, with four-port 10G and 40G versions coming a year later.
Cavium is sharing mainly high-level details of the Thunder SoCs.
Cavium will use the latest extensions of ARM's 64-bit V8 architecture, including a new exception handler (GICv3) and virtualization spec (SMMUv2). Each custom core handles out-of-order processing of up to three instructions per cycle and has a 16 Mbyte L2 cache.
In 2011 Applied Micro was the first to announce plans for a custom 64-bit ARM core. More recently AMD said it will design one, too, although it will not ship in SoCs until 2016.
Starting next year, Cavium will have a full line of ARM- and MIPS-based chips with a fair amount of overlap in the versions targeting networking systems.
"The way we see it, Thunder is more focused on cloud and data center systems and [the MIPS-based] Octeon is more embedded," says Raghib Hussain, one of Cavium's founders and its chief technology officer.
The two product lines use the same on- and off-chip interconnects, coherency protocols, and other silicon blocks. "As a result, we have the flexibility to pick and choose on a product-by-product basis whether to put in a MIPS or ARM core," says Hussain.
Nevertheless, the company now has to design two types of custom cores. "The long-term future depends on how the market evolves, but for the next generation we are committed to both" MIPS and ARM, he told us.
"I think we will see Thunder in embedded apps as well as servers," says analyst Gwennap, "so the question is over time what percent of sales will be on Thunder vs. Octeon -- over time they could shift more completely to the ARM side.
"The same thing is happening at Freescale and Broadcom -- all the major embedded guys are moving toward ARM," at the expense of MIPS and PowerPC.
— Rick Merritt, Silicon Valley Bureau Chief, EE Times