The Technology and how it works
AMD introduced the Phenom processor architecture in November 2007 with the release of chips with four internal processor cores, known as quad-core processors. These chips took the best of the incumbent Athlon architecture, which provided the backbone of AMD's desktop chip business for the previous five years, and extended the technology by having more performance via a greater number of cores - from two to four - and with architectural improvements such as extra on-chip cache.
The Phenom range was designed to compete with Intel's Core 2 Quad chips in the £150-£300 price bracket. However, after a seemingly successful launch, Phenom chips were plagued with problems, most notably the TLB bug that forced the chipmaker to release a new, updated revision, dubbed B3.
At the same time, in March 2008, AMD also released chips with three internal cores, based on the same Phenom X4 architecture, and they were called Phenom X3, unsurprisingly.
After moving on to a smaller, more-efficient manufacturing process in January 2009, from 65nm to 45nm, AMD released the Phenom II X4 range, and notable performance improvements were observed via an increase in clock-speed, from a maximum of 2.6GHz for Phenom I to 3GHz for Phenom II, and with extra L3 cache, rising from 2MB to 6MB.
Along with other minor architectural improvements, AMD's new Phenom II chips, comprising of the X4 920 (2.8GHz) and X4 940 Black Edition (3.0GHz), were priced aggressively at £160 and £190, respectively, and competed well against Intel quad-core chips in the same pricing bracket.
Phenom I and II were socket-compatible, meaning that a user who purchased an AM2+ motherboard, which formed the vast majority of supporting chipsets, could run either processor without needing to upgrade to a new board.
Now, in February 2009, AMD is introducing a new range of Phenom II chips and a new form-factor, AM3, required because the chips support both DDR2 and DDR3 memory, although not at the same time.
Present AM2+ motherboards support DDR2 only, and the increase in speed by adopting DDR3, as seen with Intel's Core i7 processor, means that the new Phenom IIs can work with either existing boards and DDR2, or with newer AM3, DDR3-only boards, due to be released this month: the choice is yours. Further, having an hybrid memory-controller means that AMD can provide some form of future-proofing as DDR3 memory becomes the de facto motherboard standard, and it is expected that next year's Phenom line-up will be almost exclusively AM3/DDR3-based.
The Phenom AM3 chips will also bring the tri-core X3 models into the fold, and two have been released this month.
As you can see, AMD has a number of processor that litter the £75-£150 space, often with overlapping pricing between tri- and quad-core models. They're further differentiated in terms of clock-speed, cache count, and form-factor, and our recommendation would go toward either the Phenom X3 720 Black Edition, priced at around £125, or the Phenom X4 920, costing some £35 more but bringing an extra processing core into play.
The eclectic range of chips compete against Intel's dual- and quad-core range, from the E8200 through to the Q9400, and the general price-to-performance ratio is such that both companies provide roughly the same performance at a given level, be it £80 or £150.
Of course, Intel has the dominant lead in areas that AMD doesn't even have chips, and the also-recently-introduced Core i7 is the fastest desktop processor around, but it costs £240 on top of the extra platform costs associated with the supporting X58 chipset and DDR3 memory.
AMD's introduction of the Phenom II processor has brought the company back into contention in the £125-£190 space. Clocked in higher than first-generation Phenom and sporting more cache, the new chips are available in two flavours: AM2+, which provides support for DDR2 memory, or AM3, which adds in DDR2/DDR3 support.
Expect to see a range of Phenom-based systems, under the Dragon branding, costing between £500-£999 at reputable system builders. On a price-to-price basis AMD competes well with Intel, and such is the value of high-end chips these days, that neither company makes a bad product.