AM2: AMD Reinvents Itself
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Page 1:The AMD Generation Comes Of Age
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Page 2:New Socket AM2 With DDR2
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Page 3:Memory Speed: Socket AM2 Vs. Socket 939
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Page 4:Write Performance
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Page 5:Write Performance, Continued
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Page 6:Write Performance, Continued
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Page 7:Memory Speed: AMD Vs. Intel
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Page 8:Memory Speed: AMD Vs. Intel, Continued
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Page 9:The Divider Problem
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Page 10:DDR2 SLI Memory: 10.3 GB Per Second
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Page 11:Automatically Overclocking SLI Memory
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Page 12:Automatically Overclocking SLI Memory, Continued
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Page 13:All New AM2 Processors
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Page 14:The New Socket AM2 With 940 Pins
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Page 15:New Retention Module Requires New Heatsink
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Page 16:Low Dissipation Guaranteed
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Page 17:New Energy-efficient Processors
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Page 18:Heatsinks: Things Gets Louder, Continued
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Page 19:Features: Virtualization And TCPA
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Page 20:Price Comparison: AMD More Expensive Than Intel
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Page 21:Motherboards
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Page 22:Gigabyte
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Page 23:Epox
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Page 24:The New nForce5 Chipset For AM2
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Page 25:LAN Interface With 2 Gbit/s
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Page 26:Test Setup
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Page 27:Benchmarks And Settings
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Page 28:Benchmarks Socket 939 Vs. Socket AM2
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Page 29:Games - DirectX
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Page 30:Games - DirectX, Continued
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Page 31:Video
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Page 32:Video, Continued
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Page 33:Video, Continued
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Page 34:Video, Continued
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Page 35:Audio
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Page 36:Applications
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Page 37:Applications, Continued
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Page 38:Applications, Continued
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Page 39:Multitasking, Continued
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Page 40:Synthetic Benchmarks
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Page 41:Synthetic Benchmarks, Continued
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Page 42:Synthetic Benchmarks, Continued
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Page 43:Synthetic Benchmarks, Continued
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Page 44:Synthetic Benchmarks, Continued
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Page 45:Evaluating The Benchmark Scores
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Page 46:Athlon 64 X2: Now Somewhat Slower
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Page 47:Benchmarks AMD Vs. Intel
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Page 48:Games - DirectX
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Page 49:Games - DirectX, Continued
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Page 50:Video, Continued
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Page 51:Audio
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Page 52:Applications
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Page 53:Applications, Continued
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Page 54:Multitasking
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Page 55:Synthetic Benchmarks
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Page 56:Synthetic Benchmarks, Continued
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Page 57:Synthetic Benchmarks, Continued
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Page 58:Synthetic Benchmarks, Continued
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Page 59:Synthetic Benchmarks, Continued
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Page 60:Synthetic Benchmarks, Continued
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Page 61:AMD Athlon 64 FX-62 Vs. Intel Extreme Edition 965
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Page 62:Conclusion: Good Energy Efficiency, But A Bad Value For Money
The Divider Problem
The DDR2 memory speeds we set, such as 736 MHz for the Athlon 64 X2 4400+, weren't chosen at random, but were assigned by the CPU.
Looking for a moment at the operation of the DDR1 interface on the old Socket 939, we see that the processor converts the CPU clock speed using a divider, in order to come up with the correct speed to use for addressing the memory. Internal memory interfaces have used DDR400 (200 MHz) since they were invented.
Athlon 64 X2 4200+: 2200 MHz / 11 = 200 MHz (DDR400)
Athlon 64 X2 3200+: 2000 MHz / 10 = 200 MHz (DDR400)
For this reason, AMD only sells CPUs with even clock speeds, which are divisible by 200 MHz, in its range.
With the switch to DDR2, AMD runs up against a problem: DDR2-800 has a clock speed of 400 MHz and can therefore no longer be divided by all previously envisaged CPU clock speeds. And the highest speed possible is not divisible by 400.
But how does the CPU react if a memory timing is set which cannot be divided by the CPU clock speed?
AMD came up with something smart here: if a divider is produced that exceeds the next possible JEDEC-compliant standard memory clock (400, 533, 667, 800), the next lower divider is selected automatically.
Athlon 64 X2 4800+: 2400 MHz / 6 = 400 MHz (DDR2-800)
Athlon 64 X2 4000+: 2000 MHz / 5 = 400 MHz (DDR2-800)
Athlon 64 X2 5000+: 2600 MHz / 7 = 371 MHz (DDR2-742)
Athlon 64 X2 4400+: 2200 MHz / 6 = 366 MHz (DDR2-733)
This produces highly curious memory clocks like DDR2-742 and DDR2-733. The automatic selection of the divider cannot be deactivated or influenced.
We therefore advise the ambitious user to grab a pocket calculator before making a purchase, and check whether the divider for the CPU tallies or not. It may be that the dependence of the memory interface on clock speed means that, despite its 200 MHz higher speed, a CPU may actually be slower when running some applications. For example:
Athlon 64 X2 4200+: 2200 MHz with DDR2-733
Athlon 64 X2 4000+: 2000 MHz with DDR2-800
If you now consider the fact that the lower memory clock speed already forced on the 2200 MHz CPU is compounded by a cache merely half the size of the less expensive 4000+ at 2000 MHz, you have to ask yourself: who can really understand all of this?
An overview of all possible memory configurations at standard clock speeds
The memory clock speeds in red are not standard and are therefore rounded down, resulting in a performance loss.
- The AMD Generation Comes Of Age
- New Socket AM2 With DDR2
- Memory Speed: Socket AM2 Vs. Socket 939
- Write Performance
- Write Performance, Continued
- Write Performance, Continued
- Memory Speed: AMD Vs. Intel
- Memory Speed: AMD Vs. Intel, Continued
- The Divider Problem
- DDR2 SLI Memory: 10.3 GB Per Second
- Automatically Overclocking SLI Memory
- Automatically Overclocking SLI Memory, Continued
- All New AM2 Processors
- The New Socket AM2 With 940 Pins
- New Retention Module Requires New Heatsink
- Low Dissipation Guaranteed
- New Energy-efficient Processors
- Heatsinks: Things Gets Louder, Continued
- Features: Virtualization And TCPA
- Price Comparison: AMD More Expensive Than Intel
- Motherboards
- Gigabyte
- Epox
- The New nForce5 Chipset For AM2
- LAN Interface With 2 Gbit/s
- Test Setup
- Benchmarks And Settings
- Benchmarks Socket 939 Vs. Socket AM2
- Games - DirectX
- Games - DirectX, Continued
- Video
- Video, Continued
- Video, Continued
- Video, Continued
- Audio
- Applications
- Applications, Continued
- Applications, Continued
- Multitasking, Continued
- Synthetic Benchmarks
- Synthetic Benchmarks, Continued
- Synthetic Benchmarks, Continued
- Synthetic Benchmarks, Continued
- Synthetic Benchmarks, Continued
- Evaluating The Benchmark Scores
- Athlon 64 X2: Now Somewhat Slower
- Benchmarks AMD Vs. Intel
- Games - DirectX
- Games - DirectX, Continued
- Video, Continued
- Audio
- Applications
- Applications, Continued
- Multitasking
- Synthetic Benchmarks
- Synthetic Benchmarks, Continued
- Synthetic Benchmarks, Continued
- Synthetic Benchmarks, Continued
- Synthetic Benchmarks, Continued
- Synthetic Benchmarks, Continued
- AMD Athlon 64 FX-62 Vs. Intel Extreme Edition 965
- Conclusion: Good Energy Efficiency, But A Bad Value For Money