Introduction

First of all, I would like to thank AMD for providing the tested AMD Athlon II X4 645 processor sample, MSI for providing the 890FXA-GD70 motherboard and Links for providing the rest of the test setup.

After few months of keeping a low profile, AMD is refreshing its whole processor retail offer from top to bottom. While introducing new and faster models with increased clock, AMD is keeping its top price bars, lowering the prices of existing models and introducing new, faster ones in their place, like the AMD Athlon II X4 645.

In this review we take a look at the new addition to Athlon II family models, the fastest quad core Athlon II yet, named Athlon II X4 645 and clocked at an impressive 3.10 GHz, considering this is to be a budget processor. Aiming to be a powerful yet affordable general purpose processor, the new Athlon II X4 645 with its faster clocked cores is stepping into the upper middle market segment, ruled by slower Phenom II models and Intel's Core i3 and i5 processors. It will be interesting to see if the Athlon II X4 Series matured enough to take on these new challenges.

Packaging and Contents

We received our test sample in tray package, but the retail version packaging comes with AMD certified cooler, manual and three year warranty.

Athlon II X4 645

Long after retiring the Phenom II X4 800 series, AMD is introducing a new member to the forgotten family, the Phenom II X4 840 quad core processor. New model comes with quite high clock frequencies and very low price tag. Low enough to raise your eyebrows in disbelief. AMD is asking just $102 for quad core Phenom II processor, and if some of you can remember, that was the starting price for 2.60 GHz Athlon II X4 620 introduced a year ago, so one would think AMD came a long way, and one would be somewhat deceived.

What AMD has done here is mix up the Athlon II quad Propus core with Phenom II brand. After introduction of Athlon II X4 645, quad core Athlon II models clocking above 3.0 GHz were starting to catch up to slower Phenom II models, so AMD decided to upgrade the low cost Propus core to Phenom II brand. In other words, what we have here is Athlon II X4 "650" renamed to Phenom II X4 800 series. In terms of specifications, it is identical to every other Athlon II X4 SKU, and the one thing that differed Athlon II from Phenom II series, L3 cache buffer is no more.

The older Phenom II X4 800 series of processors had cut down L3 cache, to 4 MB. The new Phenom II X4 800 series, starting with 840 model we have here, has no L3 cache at all. Not a big surprise since it's using Propus core, but it comes as a surprise that AMD decided to take this step, and confuse its buyers even more. But then again, for just over $100 there's no room for complaints, right?

Either way, what we have here is a budget quad core processor, based on Propus core used in Athlon II X4 and X3 series, and clocked to 3.20 GHz. Phenom II X4 840 is based on C3 revision of Propus core, just like the Athlon II X4 645 we reviewed recently, so the benefits of lower power consumption and lower heat output are present here as well. The processor's frequency multiplier is locked to x16, and only adjustable downwards, so the only way to overclock is via raising the HTT bus. Core voltage is set a bit higher than Phenom II models, to 1.40 V, but TDP is still kept to acceptable 95W.
Like any other Phenom II or Athlon II model, backwards compatibility with AM2+ boards and DDR2 memory is here, and very useful considering the market this processor is targeting.

Since we covered all of the architectural features of AMD's Propus core in our first encounter with Athlon II X4, I would like to redirect you to the X4 620 spec page of the review if you're interested in more details about the processor core itself (LINK).

Test Systems

Below you can see the entire list of programs used to test our processors. Most of the tests make good use of multithreading, but just like real-life situations, there are some tests that prefer higher clock frequencies over number of cores or size of L2/L3 cache buffer. Since Windows 7 64-bit is used from now on as base for processor benchmarks, some of benchmarks are used in 64-bit versions as well.