Introduction

If AMD's CPU group is going to turn things around and start generating a profit this year, it's imperative that they find a way to improve their overall profit margins per processor.

Normally the easiest way to improve your margins is to introduce higher-performing parts that you can charge a premium price for. Getting high-end Phenom II CPUs out the door earlier this year was key to that strategy for AMD and it was beginning to work, with PC vendors like Dell introducing gaming-oriented XPS PCs based around AMD CPUs for the first time.

The recent arrival of Intel’s Lynnfield CPUs however puts a major obstacle in front of those plans. Charging anything over Intel’s $200 asking price for the Core i5-750 is now impossible for any Phenom II CPU considering the performance of Intel’s latest mainstream processor.

Without a high-end, premium-priced CPU to rely on, AMD’s instead going to have to improve their profit margins on the low-end of their CPU lineup. In other words, they’ve got to make these CPUs cheaper to produce. The key to making this happen is their new 45-nm manufacturing process.

As we mentioned in our Phenom II X2 550/Athlon II X2 250 article, the lion’s share of AMD’s entry-level CPU lineup is based around existing 65-nm Athlon X2 CPUs. Some of these chips are even parts based on their old K10 Kuma core used in Phenom CPUs. The 65-nm Athlon X2 7850 is one such chip, it features a 285mm2 die size. To put that in perspective, the die size of AMD’s latest Phenom II X4 965 is just 258mm2, with the core featuring over 750 million transistors (Kuma has 450 million transistors).

Taking quad-core CPUs to new price points

With this in mind, AMD’s currently racing to switch from these large 65-nm chips to purpose-built 45-nm designs that are built from the ground up to service the value CPU segment. The 45-nm Regor core used in AMD’s Athlon II X2 250 for example contains 234 million transistors with a die that measures just 117.5mm2. This CPU core has been tailored specifically for the entry-level dual-core CPU market.

Now AMD’s targeting entry-level quad-core. As software that’s capable of taking advantage of more than two threads becomes more pervasive, the need for quad-core CPUs increases. It isn’t cost-effective for AMD to address this segment with the Deneb core found in today’s latest Phenom II processors. Its 6MB L3 cache takes up a huge chunk of real estate on the CPU’s die.

As such, AMD’s decided to remove it entirely. That’s right, their entry-level 4-core Athlon II X4 CPU, which utilizes the “Propus” core, eliminates the L3 cache completely. Without a third level cache, Propus’ die measures 169mm2. Here’s what it looks like in the flesh:

AMD’s introducing two new CPUs based on Propus today, the Athlon II X4 630 and Athlon II X4 620. Priced at $99 and $122 respectively, AMD feels they’ve hit the sweet spot when it comes to quad-core price/performance.

We’ve secured samples of both chips to see how they stack up against the competition in terms of performance, OC’ing, and power consumption. If you recall, one of Phenom’s key weaknesses was its tiny 2MB L3 cache. This crippled its performance in comparison to competing Intel quad-core CPUs. Can Propus keep up with Intel’s popular Core 2 Quad 8000-series CPUs?