CPU performance and clock speed have leveled out over the last several years. What does this mean for the industry?
Strictly speaking, Moore’s law says that the number of transistors on a chip will double every 18 to 24 months. And that’s been true for the last 40 years. And it appears set to continue for another decade.
But Moore’s observation has been simplified to mean a doubling of performance every 18 to 24 months. And that too has been true. But not anymore.
Transistors and performance do not have a one-to-one relationship. Yes, clock speeds have improved from the 1 MHz 6502 processor in the original Apple II to over 3 GHz in the latest and greatest. But we’ve reached the end of the line in clock speed improvements: in a third of a nanosecond light moves about 4 inches or 10 cm. Not much distance when chips have miles of internal wiring.
But clock speed isn’t the whole story. Chips now move data in 64 and 128-bit chunks, rather than the 6502’s 8-bit chunks. While there are experiments with Very Long Word computer architectures, as a practical matter we were also at the end of the line for wider data paths as well: 256 bits is as wide as personal and commercial processors can reasonably use.
More RAM? We’ve also been adding ever-larger on-chip caches that improve performance. But inevitably cache-hit ratios decline with size and so do the performance benefits.
We can’t make processors go faster. We can’t process more data per clock cycle. So how do we put twice as many transistors to work?
Stuffing more processors on a chip. And right now many of the brightest minds in computer science are struggling with the problem of getting usable work out of 8, 12 or 16 core CPUs.
Dual and quad core processors work pretty well because our multitasking operating systems run a lot of background threads. Spreading those threads across multiple cores improves performance for everyone.
But outside video, image, voice and scientific apps, most of what we do today – word processing, e-mail, web surfing, spreadsheets and presentations – don’t need multicore architectures. Certainly not 8 or more cores. Humans aren’t good multi-taskers.
We’ve hit a technology wall. We can still double the number of transistors on a chip every couple of years. We can still double disk drive capacity every 2 to 3 years. We can build faster interconnects, such as QuickPath, Light Peak and 10 Gb Ethernet.
But the easy wins are over. Going forward performance gains will be measured in single digit percents each year.
Information technology, like most of the US economy, is driven by consumer spending. So what happens when a new PC is only 20% faster than your fully paid for three-year-old PC?
Digital Equipment Corporation, who pioneered the minicomputer in the 1960s, had a simple model for product improvements. A successful product would add functionality and performance at a constant cost. And they would offer the same functionality and performance at a declining cost. Here’s a graph of their model:
At some point the cost of producing a given level of functionality would be so low that distribution and marketing costs would dominate. Then volumes would migrate to the price performance sweet spot and lower volume products died.
Today, we can no longer count on performance increases to open up new application territory. Therefore we will see differentiation move to what were once considered secondary characteristics.
- Power. The server space is grappling with the implications of greater power efficiency, but the mobile space has been pushing this metric for the last 15 years. That will continue for years to come.
- Integration. Open up in iPad or a MacBook Air and what do you see? A tiny PC board, a few chips and a huge set of batteries. Long battery life is what makes the product so convenient that they become part everyday life.
- Functionality. Creatively integrating multiple applications, each with their own dedicated core, may enable consumer devices to collapse multistep workflows into a single handy device. Combine image capture, voice recognition, editing and compression into a single device that would enable consumers to capture, edit and post video from a single candy bar sized device, editing on-the-fly with spoken commands.
- Cost. The first low-res digital cameras cost hundreds of dollars, but today we build them into cheap cell phones.
The StorageMojo take
The days of the Moore’s Law driven application growth are over. The next step is to use our still growing technical capabilities to refine what we already do.
The good news for the storage industry is that new data production will continue to grow rapidly. Always on, always available consumer data systems will create ever more demand for storage.
This is also another nail in the coffin of the RAID controller paradigm. Distributed multicore processing power requires distributed data protection and storage architectures.
When you can’t scale up, you have to scale out. Decomposable storage architectures will inevitably come to the fore.
Courteous comments welcome, of course. Oddly enough, the Apple ][ motherboard’s style was the same as today’s MacBook Air: a few chips on a PC board. Friends were always startled to see empty my Apple ][‘s case was.