Specifications: Up to 1.86 GHz

Intel will offer two different versions of Atom. We still have to wait for the dual-core and 64-bit capable Diamondville, the (32-bit) Silverthorne was rolled out today in five versions:

- Atom Z500, 800 MHz clock speed, 512 KB L2 cache, FSB400, 0.65 watt TDP
- Atom Z510, 1.1 GHz, 512 KB, FSB400, 2 watt
- Atom Z520, 1.33 GHz, 512 KB, FSB533, Hyperthreading, 2 watt
- Atom Z530, 1.60 GHz, 512 KB, FSB533, Hyperthreading, 2 watt
- Atom Z540, 1.86 GHz, 512 KB, FSB533, Hyperthreading, 2.4 watt

Since these processors are compatible with the Core 2 Duo (Merom), these CPUs have a very similar general feature set, which includes support for VT (virtualization), execute disable bit, SSE3 and SSSE3 instructions.

Features: 1.2 GHz at 43 degrees

The core of Silverthorne is built around a 16-stage processor pipeline, including three instruction phase stages - three for instruction decode, two for instruction dispatch and three for data cache access. Fetch and decode are supported by a 32 KB instruction cache with pre-decode extension, a 128-entry branch trace buffer as well as return stack buffers (2-deep for fetch and 8-deep for decode). The pipeline can schedule 16 entries per thread; two operations can be picked up from either thread per clock.

On the performance side, macro-op support in Silverthorne/Diamondville is one key component that is responsible for the acceleration of the instruction processing. Moving towards a coarse-grained processing method and combining micro-ops into macro-ops, the company said it achieves what a higher decoding and scheduling efficiency. 96% of all instructions are micro-ops and the effective macro-op load-to-use latency is "zero clocks", Intel told us. A longer branch-miss prediction is the downside of using macro-ops, which however, was apparently acceptable in exchange for the performance gain.

A rather surprising feature is the support of Hyperthreading (HT) or "Simultaneous Multithreading (SMT)", which is the new official name for this technology. The three higher-end SKUs of Silverthorne integrate SMT (1.33 GHz, 1.6 GHz, 1.86 GHz) and represent one physical and one additional virtual core. A future dual-core Diamondville processor will be able to handle four threads simultaneously.

While you may wonder why dual-thread support made its way into a processor that isn’t supposed to run Photoshop and video editing software, Intel said that in consideration of its available power budget, SMT was a cheap and very efficient method to increase the CPU’s performance-per-watt rating. SMT also helps to scale the processor to higher performance ratings down the road.