AMD Athlon II X4 645 review

Is AMD's £95 quad-core chip a bargain buy or cheap tat?

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The ageing nature of AMD's CPU architecture has its downsides, but there are also benefits for anyone hoping to build a decent rig on a tight budget. The AMD Athlon II X4 645 is a quad-core chip based on the finest processor cores AMD can currently muster, despite being a budget CPU.

In other words, we're talking four 45nm cores complimented by AMD's on-die memory controller and speedy HyperTransport interconnect. Putting clockspeed to one side, the only architectural advantage enjoyed by AMD's Phenom II CPUs is a dollop of shared L3 cache memory. The Athlon II models must survive with 512KB L2 per core. Still, the 645 has a healthy stock clockspeed of 3.1GHz, helping to offset the missing L3 cache.

The comparison with Intel processors, of course, is another matter. The Core i5 quad-core CPU may not be the most advanced Intel has to offer, but it's still a much more modern architecture.

In thread-heavy applications, the 645 puts on a good show. We reckon few people will really notice that their CPU completes a 3D rendering job in one minute and 16 seconds rather than the minute flat of the more powerful quads from AMD and Intel. Likewise, 17 frames per second compared to 20 frames per second when video encoding is surely close enough.

Where the performance gap is more critical is gaming. A few extra frames per second here can really make the difference between silky smooth and jerky junk. The 645 is well behind the Phenom II X4 970, much less Intel's lightning quick Core i5-760. Admittedly, the 645's 50fps average looks okay, but the occasional choppiness in our World of Conflict benchmark is unmistakable.

We liked

A four-core chip for chump change is an attractive idea. The Athlon II X4 645 isn't quite as cheap as we'd like, but it's still extremely affordable and delivers excellent threading performance for the money. That's thanks in no small part to its healthy 3.1GHz clockspeed.

We disliked

In the broader context of the cost of building a PC, £40 to £50 is not a huge sum. With that in mind, we'd be tempted to pass over the Athlon II X4 645 and spend a bit more on one of AMD's full-power Phenom II chips. That's especially true if gaming performance is a high priority. The cut-down cache hurts the 645's framerates.

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Tech Specs

Product TypeProcessor
Processor CoreQuad-core (4 Core)
Thermal Design Power95 W
Processor ManufacturerAMD
Product FamilyAthlon II X4
Clock Speed3.10 GHz
Processor SocketSocket AM3 PGA-938
Brand NameAMD
Green CompliantYes
Green Compliance Certificate/AuthorityRoHS
64-bit ProcessingYes
L2 Cache2 MB
ManufacturerAdvanced Micro Devices, Inc
Product Model645
Product NameAthlon II X4 Quad-core 645 3.1GHz Desktop Processor
Product LineAthlon II X4
Manufacturer Part NumberADX645WFGMBOX
Manufacturer Website Address
Marketing Information

Do more in less time with amazing multi-core performance at a great price

Do more of the things you want to in less time and enhance your digital life with the multi-core performance and energy efficiency of AMD Athlon II processor-based desktop systems. Combined with superior ATI Radeon HD graphics technology, systems based on the AMD Athlon II processor deliver a vivid visual experience, superior multi-tasking, and exceptional digital media performance with next-generation energy efficiency.

Process Technology45 nm
Package Contents
  • Athlon II X3 Tri-core 450 3.2GHz Desktop Processor
  • AMD-qualified Heatsink/Fan with Thermal Interface
  • Installation Manual
  • AMD Processor Case Sticker
  • Certificate of Authenticity
Limited Warranty3 Year