On AMD64 processors with the new CG stepping: how to distinguish
As you know, during the life cycle each processor undergoes several technological revisions that result in the new steppings with new or improved features. The new CG stepping of AMD Athlon 64, Mobile Athlon 64 DTR, Mobile Athlon 64, Athlon 64 FX processors will differ from the previous C0 by some serious improvements, mostly energy saving.
More information of CG stepping is provided in the AMD Athlon 64 Processor Power and Thermal Data Sheet v3.11 updated in January 2004. The Athlon 64 with the new CG stepping has the new marking. E.g. desktop Athlon 64 marks...
...now have the following additions:
According to this document, the same is made to other desktop and mobile AMD64 processors with the new stepping.
Our colleagues from Heise.de compiled a table of the old- and new-stepping processors:
| CPU | Clock | Old stepping |
New stepping |
| Athlon 64 (ClawHammer, 512/1024 KB L2 cache), Socket 754 |
| 3400+ (1024KB L2) | 2200MHz | C0 (F48h)
ADA3400AEP5AP | CG (F4Ah)
ADA3400AEP5AR |
| 3200+ (1024KB L2) | 2000MHz | C0 (F48h)
ADA3200AEP5AP | CG (F4Ah)
ADA3200AEP5AR |
| 3000+ (512KB L2) | 2000MHz | C0 (F48h)
ADA3000AEP4AP | CG (F4Ah)
ADA3000AEP4AR |
| Mobile Athlon 64 DTR (ClawHammer, 1024KB L2 cache), Socket 754 |
|---|
| 3400+ (1024KB L2) | 2200MHz | C0 (F48h)
AMA3400BEX5AP | CG (F4Ah)
AMA3400BEX5AR |
| 3200+ (1024KB L2) | 2000MHz | C0 (F48h)
AMA3200BEX5AP | CG (F4Ah)
AMA3200BEX5AR |
| 3000+ (1024KB L2) | 1800MHz | C0 (F48h)
AMA3000BEX5AP | CG (F4Ah)
AMA3000BEX5AR |
| Mobile Athlon 64 (ClawHammer, 1024KB L2 cache), Socket 754 |
|---|
| 3200+ (1024KB L2) | 2000MHz | C0 (F48h)
AMN3200BIX5AP | CG (F4Ah)
AMN3200BIX5AR |
| 3000+ (1024KB L2) | 1800MHz | C0 (F48h)
AMN3000BIX5AP | CG (F4Ah)
AMN3000BIX5AR |
| 2800+ (1024KB L2) | 1600MHz | C0 (F48h)
AMN2800BIX5AP | CG (F4Ah)
AMN2800BIX5AR |
| Athlon 64 FX (SledgeHammer, 1024KB L2 cache), Socket 940 |
|---|
| FX-51 (1024KB L2) | 2200MHz | C0 (F58h)
ADAFX51CEP5AK | CG (F5Ah)
ADAFX51CEP5AT |
And now let´s describe the changes that the new stepping implies. Note this table of features of Athlon 64 (Desktop) with CG stepping:
As you can see, the Cool´n´Quit technology was changed in these processors. Unlike C0-stepping chips which have energy saving mode at 800MHz, 1.30V and respective 35W TDP, the CG stepping differs by Cool´n´Quiet at 1000MHz, but 1.10V and thus 22W TDP. The full-clock mode remains the same 1.5V and 89W TDP, however they added another intermediate energy-saving state for Athlon 64 3400+, p-State #2 at 1.80GHz and 1.30V.
Another significant change in the new stepping is the reduced requirements for AMD64 interface logic energy consumption: now Desktop, DTR and Mobile Athlon 64 models have I/O Power at 160mW (vs. 600mW for the previous stepping). Athlon 64 FX have this value reduced from 1.4W to 0.4W.
Despite that the new stepping has the same TDP, the new "relieved" modes mean the significant offload of CPU cooling systems and the improvement of the thermal conditions in general.
Whether all these improvement are useful, only the tests will tell. Still don´t forget that all of them are actual for motherboards which BIOS supports Cool´n´Quiet.
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