AMD revealed yesterday some of the high-level changes it would be bringing to Steamroller, the product code name for its next CPU refresh. According to AMD's slides and analysis by the Tech Report, the latest revision to the Bulldozer architecture should boost overall performance while reducing power usage.
One of Bulldozer's signature changes was the removal of what AMD saw as redundant hardware—instead of each CPU core having its own decode hardware, floating-point units, and L2 cache, these resources were shared between two cores, ostensibly to reduce the size (and thus, the power consumption) of the processor. Steamroller retains the shared FPUs and L2 cache, but backtracks a bit and provides each CPU core with dedicated decode hardware that AMD's slides claim will "feed the cores faster."
To compensate for the higher power consumption required by the decode hardware, AMD has taken steps to streamline the shared FPUs to reduce the amount of transistors the units need without impacting performance. The L2 cache has also been changed—the cache can now be "resized" (or even disabled entirely) by turning parts of itself on and off dynamically depending on the CPU's current workload. This is a natural extension of a power-saving trick that both Intel and AMD chips have been using for a while now—modern chips from both manufacturers can turn entire CPU cores off when they're not in use, saving power when devices are idling and giving the processors the thermal headroom they need to ramp up CPU speeds for single-threaded tasks (this is what Turbo Boost is all about).
Some additional power savings will be achieved by the move from a 32nm process to a 28nm process, though that jump won't be as significant as the move from 45nm to 32nm, or the move from 32nm to 22nm.
These changes look to be solid improvements to AMD's Bulldozer CPU architecture, which has had a rough time of it. When it originally launched, it was not only late to market, but also lower-performing and more power-hungry than anticipated—in some cases, it couldn't even outperform its predecessor. The first revision to Bulldozer, codenamed Piledriver, helped AMD's most recent laptop CPUs achieve slightly better performance and substantially better battery life, but the chips had trouble matching the performance of Intel's then-current Sandy Bridge chips, to say nothing of the more recent Ivy Bridge products (and we're still waiting for boxed versions of Piledriver-based desktop CPUs, though they have begun shipping to OEMs). Steamroller probably won't help AMD catch up to Intel, whose newest Haswell chips are already on the horizon, but it should help keep the chips competitive at the low and middle ends of the consumer market.
Performance aside, AMD's biggest problem right now is a distinct lack of presence, especially in laptops: it's very difficult to find laptops using AMD CPUs outside of the budget market, as we saw in our recent laptop buyers' guide. Hopefully Steamroller-based chips are appealing enough to stoke some competition in market segments with higher margins, which would be good for AMD, and better build quality, which would be good for consumers.
