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CPU Core Details

CPU Codename Callisto Propus
MoBo Socket Socket AM2+ / AM3 Socket AM3
Notebook CPU no no
Release Date 01 Jan 2011 21 Sep 2010
CPU Link GD Link GD Link

CPU Technical Specifications

CPU Cores 4 4
CPU Threads 4 4
Clock Speed 3.4 GHz 3.1 GHz
Turbo Frequency - -
Max TDP 159 W 95 W
Lithography 45 nm 45 nm
Bit Width - 64 Bit
Max Temperature - 71°C
Virtualization Technology no no

CPU Cache and Memory

L1 Cache Size 512 KB 512 KB
L2 Cache Size 2048 KB 2048 KB
L2 Cache Speed - -
L3 Cache Size 6 MB -
Memory Types
Memory Channels 2 2
ECC Memory Support no no

CPU Graphics

Integrated Graphics no no
Base GPU Frequency - -
Max GPU Frequency - -
DirectX - -
Displays Supported - -

CPU Mini Review

Mini Review This is the unlocked version of the Phenom II X2 B59. Athlon II X4 645 is a performance processor based on the 45nm, K10 micro-architecture. It offers 4 Physical Cores (4 Logical), clocked at 3.1GHz and 2MB of L2 Cache. Among its many features, Virtualization is activated. The processor DOES NOT integrate any graphics. and has a rated board TDP of 95W. It is a powerful processor whose performance is good. It's thus capable of running most applications smoothly without any problem.

Gaming Performance Comparison

In terms of overall gaming performance, the AMD Athlon II X4 559 is marginally better than the AMD Athlon II X4 645 when it comes to running the latest games. This also means it will be less likely to bottleneck more powerful GPUs, allowing them to achieve more of their gaming performance potential.

Both the Athlon II X4 559 and the Athlon II X4 645 were released at the same time, so are likely to be quite similar.

Both CPUs exhibit very powerful performance, so it probably isn't worth upgrading from one to the other, as both are capable of running even the most demanding games at the highest settings (assuming they are accompanied by equivalently powerful GPUs).

{ The X4 559 and the X4 645 both have 4 cores, which is not likely to be a limiting factor for gaming.

Both the AMD Athlon II X4 559 and the AMD Athlon II X4 645 have the same number of threads. Both CPUs have one thread per physical core.

Multiple threads are useful for improving the performance of multi-threaded applications. Additional cores and their accompanying thread will always be beneficial for multi-threaded applications. Hyperthreading will be beneficial for applications optimized for it, but it may slow others down. For games, the number of threads is largely irrelevant, as long as you have at least 2 cores (preferably 4), and hyperthreading can sometimes even hit performance.

More important for gaming than the number of cores and threads is the clock rate. Problematically, unless the two CPUs are from the same family, this can only serve as a general guide and nothing like an exact comparison, because the clock cycles per instruction (CPI) will vary so much.

The X4 559 and X4 645 are not from the same family of CPUs, so their clock speeds are by no means directly comparable. Bear in mind, then, that while the X4 559 has a 0.3 GHz faster frequency, this is not always an indicator that it will be superior in performance, despite frequency being crucial when trying to avoid GPU bottlenecking. As such, we need to look elsewhere for more reliable comparisons.

Aside from the clock rate, the next-most important CPU features for PC game performance are L2 and L3 cache size. Faster than RAM, the more cache available, the more data that can be stored for lightning-fast retrieval. L1 Cache is not usually an issue anymore for gaming, with most high-end CPUs eking out about the same L1 performance, and L2 is more important than L3 - but L3 is still important if you want to reach the highest levels of performance. Bear in mind that although it is better to have a larger cache, the larger it is, the higher the latency, so a balance has to be struck.

The X4 559 and the X4 645 have the same L2 cache size, but the X4 645 does not appear to have an L3 cache, so the X4 559 definitely wins out in this area.

The maximum Thermal Design Power is the power in Watts that the CPU will consume in the worst case scenario. The lithography is the semiconductor manufacturing technology being used to create the CPU - the smaller this is, the more transistors that can be fit into the CPU, and the closer the connections. For both the lithography and the TDP, it is the lower the better, because a lower number means a lower amount of power is necessary to run the CPU, and consequently a lower amount of heat is produced.