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Okay.. I found this article and i couldnt find anything like it on this forum, so i figured id post it up. I do not take any credit for the creation of this article. The article is written for 3700+ chips, but the 4000+ have the same steppings. 
This FAQ was co-written by Namrac and Rustynator over at overclock.net forums. Give all credit to them
Introduction
For the past few years the Opteron range of AMD CPU’s has been the kingpin in terms of overclockability and price. However, recently the AMD 3700+ has taken the limelight away from the Opterons, by matching its overclocking prowess and in many cases superseding it. For this reason the 3700+ is now perhaps the single most popular CPU in the overclocking community. There are actually 2 forms of the 3700+…the S754 Clawhammer version and the S939 San Diego version. We will only concentrate on the latter as this is the popular and very overclockable version.
How well a CPU, in this case a 3700+, overclocks is very much dependant on a couple of major factors:
1) The stepping of the CPU
2) The cooling on the CPU
Almost all 3700+’s are capable of overclocking past 2.6GHz (from the stock speed of 2.2GHz), but there are certain steppings which are capable of well over 3.2GHz on simple air cooling. Examples of these steppings are the KAB3E 0547GPMW and the KACAE 0602GPMW. On the other hand there are steppings that do not overclock well on air, but do wonderfully when put under phase change, like the CCBWE steppings. And then there are steppings that are simply dreadful, like the infamous CABGE stepping. This guide will introduce you to some of the more common steppings of this processor, showing where each one shines, and which steppings to avoid if possible.
Revisions
The S939 3700+ has two main revisions - the older SH-E4, and the newer E6. There are several subtle differences between the two, which are explained in this FAQ by dangerousHobo - http://www.overclock.net/faqs/85007-...md-3700-a.html. In general it is the older E4 3700+’s which produce the better overclocking results, but the E6 3700+’s do have a better memory controller.
Common steppings
Here are some of the more common steppings of the 3700+ San Diego, along with little factoids and typical overclocks to expect on each. These overclocks are only typical, prime95 stable overclocks, achieved on a good air-cooling setup. The overclocking results for a particular group of stepping can vary hugely, so the overclocking results should not be taken as a guarantee as to how well your CPU will perform. The best example of this is the KAB2E which is capable of between 2.8GHz and 3.1 GHz depending the manufacturing week/year.
KAB1E - Relatively new stepping, reasonable air overclocker. Expect ~ 2.8GHz
KAB2E – Comes in 2 varieties. The older KAB2E’s from mid-late 2005 are decent overclockers which overclock to around 2.9GHz. The newer 2006 KAB2E’s are overclocking like gems at the moment. An example of this is Crash’s and Krunk Kracker’s, which overclock to around 3-3.1GHz. In general KAB2E’s require a lot of voltage to reach the higher overclocks.
KAB3E - A better overclocker and much rarer stepping than the older KAB2E’s. They still require larger Vcore’s to reach the higher speeds but expect ~ 3GHz.
KABNE – An unusual stepping which is hard to get hold of. It performs similarly to the KAB3E so is capable of ~ 3Ghz.
KABYE – Again a rare 3700+ stepping which performs well. Expect ~ 2.9-3GHz
KABQE – As with the KABNE and KABYE, the KABQE is a scarce 3700+ stepping but actually overclocks better the 2 aforementioned steppings. A typical overclock would be just over 3GHz with low Vcore.
KACAE - Possibly the best chip for air cooling and can reach very high speeds with low voltage. Most KACAE’s will achieve >3GHz, but some steppings (i.e. the 0602GPMW) are capable of 3.2GHz! Unlike the KAB2E’s they do not seem to scale well with Vcore and tend to perform best when at a lower Vcore.
CCBWE - This is and example of an E6 revision 3700+ and is commonly thought of as a Toledo core CPU with one core disabled. A CCBWE will not perform too well on air cooling (around 2.8GHz) but will do very well on sub-zero cooling such as Phase-Change cooling.
CABGE - Old stepping which is not as common lately. Just like the Opteron 146 CABGE they are in general bad overclockers which will usually only reach 2.6GHz-2.7GHz. Fear the cabbage!
KABGE – Similar the cabbage above. They do slightly better and overclock to around ~2.7GHz but still don’t come close to the superior later steppings.
All the above steppings apart from the CCBWE are E4 revisions of the 3700+. Many shops actually sell both the E4 and E6 versions of the 3700+ so make sure you look into which revision you would like before purchasing your 3700+.
Ideal steppings for your cooling solution
Each steppings perform differently with various cooling methods. Here are the three main cooing methods, and the ideal steppings for that particular method.
Air Cooling
The most common cooling method, whether this is because of its low cost or the ease to setup, it is used by all but the most enthusiastic overclockers. A good air-cooler (such as the TTBT and Tuniq Tower) can maintain a load temp of approximately 40-45C depending on the Vcore and ambient temps.
The best general stepping for air cooling is the KACAE. It is capable of reaching very high speeds with fairly low voltage, making it ideal for the relatively inefficient air cooling method. Owners can reach high speeds and still not worry about their chip getting to hot. However, the KACAE tends to hit a wall in the range of 3.1-3.2Ghz, and requires a ton of voltage to get much higher, making it a poor water cooling chip. Also, the KACAE is cold bugged, along with most other well-performing air cooling steppings.
There are other specific steppings that do very well on air, such as the KAB3E 0547GPMW, which is considered to be the joint very best San Diego for overclocking along with the KACAE 0602GPMW. It reaches high speeds with low voltages like the KACAE, but seems to lack the voltage wall.
Water Cooling
A good custom water cooling setup will cost around $200-300 and will surpass most air coolers. The average temps for a well setup WC loop will be around 33-38C. The superior temps will aid the overclocks of almost all 3700+ steppings in comparison to air cooling, which can limit the overclock of a CPU due to excess heat. For this reason, the best steppings for water cooling are similar to air cooling.
Phase-Change Cooling
Phase-change cooling is the next step up for any serious overclocker, and will often allow you to reach temps close to -60C in the evaporator head, and -30 to 5C CPU load temps. Retail phase-change cooler, such as the Vapochill and Prommy, cost around $800, whereas a custom built cooler will cost close to $600 (word is going around that TheWaxShop is going to build custom phase-change coolers).
These phenomenal temperatures have a huge benefit on the overclocks of most steppings, often allowing them to reach speed 200-400MHz higher than water/air cooling. However, this is not always the case, as many steppings cold-bug at these sub-zero temperatures. As a rule of thumb I would say that if a stepping performs well on air cooling (i.e. the KACAE) it is going to cold-bug under phase-change. The CCBWE is an ideal CPU for the phase cooler though and can be pushed to over 3.2GHz.
Getting hold of a particular 3700+ stepping
Some people prefer to take a chance on the stepping and order a retail/OEM 3700+ online. Conversely, there are those who would like a particular “golden” stepping in order to ensure getting a good overclock. Here are 3 ways of getting your hands on a golden stepping:
1) eBay – As long as care is taken to ensure a safe transaction (for example checking feedback and using a safe payment method) eBay is the perfect place to find a stepping for a cheap price. If the stepping of the CPU is not listed just send a message to the seller requesting the info.
2) Forums – The “For Sale” sections of forums often contain great steppings, along with pre-tested overclocking results for the CPU. Again, take care to avoid trolls who scam people.
3) Websites – Tankguys.biz is an example of a site which will allow you to pick a particular stepping as long as they are in stock. You will pay a little extra for this option, but unlike the 2 methods mentioned above you are guaranteed a safe transaction.
Finally…the top three AMD 3700+ steppings to look out for
If you can get your mitts on any one of the below steppings then you will most likely not be disappointed:
1) KACAE 0602GPMW
2) KAB3E 0547GPMW
3) KAB2E 0549EPDW
Conclusion
As you can see, the 3700+ San Diego is an amazing chip. However, remember that while steppings can be a good indicator of the potential overclocking performance, they are by no means a garauntee. We have assembled a thread of overclocking results for different 3700+ SD steppings on Overclock.net, you can find it here: http://www.overclock.net/amd-cpus/10...ners-past.html
This FAQ was co-written by Namrac and Rustynator. So if you're going to rep one of us, please rep both of us, as we did equal amounts of work creating this FAQ.
This FAQ was co-written by Namrac and Rustynator over at overclock.net forums. Give all credit to them
Introduction
For the past few years the Opteron range of AMD CPU’s has been the kingpin in terms of overclockability and price. However, recently the AMD 3700+ has taken the limelight away from the Opterons, by matching its overclocking prowess and in many cases superseding it. For this reason the 3700+ is now perhaps the single most popular CPU in the overclocking community. There are actually 2 forms of the 3700+…the S754 Clawhammer version and the S939 San Diego version. We will only concentrate on the latter as this is the popular and very overclockable version.
How well a CPU, in this case a 3700+, overclocks is very much dependant on a couple of major factors:
1) The stepping of the CPU
2) The cooling on the CPU
Almost all 3700+’s are capable of overclocking past 2.6GHz (from the stock speed of 2.2GHz), but there are certain steppings which are capable of well over 3.2GHz on simple air cooling. Examples of these steppings are the KAB3E 0547GPMW and the KACAE 0602GPMW. On the other hand there are steppings that do not overclock well on air, but do wonderfully when put under phase change, like the CCBWE steppings. And then there are steppings that are simply dreadful, like the infamous CABGE stepping. This guide will introduce you to some of the more common steppings of this processor, showing where each one shines, and which steppings to avoid if possible.
Revisions
The S939 3700+ has two main revisions - the older SH-E4, and the newer E6. There are several subtle differences between the two, which are explained in this FAQ by dangerousHobo - http://www.overclock.net/faqs/85007-...md-3700-a.html. In general it is the older E4 3700+’s which produce the better overclocking results, but the E6 3700+’s do have a better memory controller.
Common steppings
Here are some of the more common steppings of the 3700+ San Diego, along with little factoids and typical overclocks to expect on each. These overclocks are only typical, prime95 stable overclocks, achieved on a good air-cooling setup. The overclocking results for a particular group of stepping can vary hugely, so the overclocking results should not be taken as a guarantee as to how well your CPU will perform. The best example of this is the KAB2E which is capable of between 2.8GHz and 3.1 GHz depending the manufacturing week/year.
KAB1E - Relatively new stepping, reasonable air overclocker. Expect ~ 2.8GHz
KAB2E – Comes in 2 varieties. The older KAB2E’s from mid-late 2005 are decent overclockers which overclock to around 2.9GHz. The newer 2006 KAB2E’s are overclocking like gems at the moment. An example of this is Crash’s and Krunk Kracker’s, which overclock to around 3-3.1GHz. In general KAB2E’s require a lot of voltage to reach the higher overclocks.
KAB3E - A better overclocker and much rarer stepping than the older KAB2E’s. They still require larger Vcore’s to reach the higher speeds but expect ~ 3GHz.
KABNE – An unusual stepping which is hard to get hold of. It performs similarly to the KAB3E so is capable of ~ 3Ghz.
KABYE – Again a rare 3700+ stepping which performs well. Expect ~ 2.9-3GHz
KABQE – As with the KABNE and KABYE, the KABQE is a scarce 3700+ stepping but actually overclocks better the 2 aforementioned steppings. A typical overclock would be just over 3GHz with low Vcore.
KACAE - Possibly the best chip for air cooling and can reach very high speeds with low voltage. Most KACAE’s will achieve >3GHz, but some steppings (i.e. the 0602GPMW) are capable of 3.2GHz! Unlike the KAB2E’s they do not seem to scale well with Vcore and tend to perform best when at a lower Vcore.
CCBWE - This is and example of an E6 revision 3700+ and is commonly thought of as a Toledo core CPU with one core disabled. A CCBWE will not perform too well on air cooling (around 2.8GHz) but will do very well on sub-zero cooling such as Phase-Change cooling.
CABGE - Old stepping which is not as common lately. Just like the Opteron 146 CABGE they are in general bad overclockers which will usually only reach 2.6GHz-2.7GHz. Fear the cabbage!
KABGE – Similar the cabbage above. They do slightly better and overclock to around ~2.7GHz but still don’t come close to the superior later steppings.
All the above steppings apart from the CCBWE are E4 revisions of the 3700+. Many shops actually sell both the E4 and E6 versions of the 3700+ so make sure you look into which revision you would like before purchasing your 3700+.
Ideal steppings for your cooling solution
Each steppings perform differently with various cooling methods. Here are the three main cooing methods, and the ideal steppings for that particular method.
Air Cooling
The most common cooling method, whether this is because of its low cost or the ease to setup, it is used by all but the most enthusiastic overclockers. A good air-cooler (such as the TTBT and Tuniq Tower) can maintain a load temp of approximately 40-45C depending on the Vcore and ambient temps.
The best general stepping for air cooling is the KACAE. It is capable of reaching very high speeds with fairly low voltage, making it ideal for the relatively inefficient air cooling method. Owners can reach high speeds and still not worry about their chip getting to hot. However, the KACAE tends to hit a wall in the range of 3.1-3.2Ghz, and requires a ton of voltage to get much higher, making it a poor water cooling chip. Also, the KACAE is cold bugged, along with most other well-performing air cooling steppings.
There are other specific steppings that do very well on air, such as the KAB3E 0547GPMW, which is considered to be the joint very best San Diego for overclocking along with the KACAE 0602GPMW. It reaches high speeds with low voltages like the KACAE, but seems to lack the voltage wall.
Water Cooling
A good custom water cooling setup will cost around $200-300 and will surpass most air coolers. The average temps for a well setup WC loop will be around 33-38C. The superior temps will aid the overclocks of almost all 3700+ steppings in comparison to air cooling, which can limit the overclock of a CPU due to excess heat. For this reason, the best steppings for water cooling are similar to air cooling.
Phase-Change Cooling
Phase-change cooling is the next step up for any serious overclocker, and will often allow you to reach temps close to -60C in the evaporator head, and -30 to 5C CPU load temps. Retail phase-change cooler, such as the Vapochill and Prommy, cost around $800, whereas a custom built cooler will cost close to $600 (word is going around that TheWaxShop is going to build custom phase-change coolers).
These phenomenal temperatures have a huge benefit on the overclocks of most steppings, often allowing them to reach speed 200-400MHz higher than water/air cooling. However, this is not always the case, as many steppings cold-bug at these sub-zero temperatures. As a rule of thumb I would say that if a stepping performs well on air cooling (i.e. the KACAE) it is going to cold-bug under phase-change. The CCBWE is an ideal CPU for the phase cooler though and can be pushed to over 3.2GHz.
Getting hold of a particular 3700+ stepping
Some people prefer to take a chance on the stepping and order a retail/OEM 3700+ online. Conversely, there are those who would like a particular “golden” stepping in order to ensure getting a good overclock. Here are 3 ways of getting your hands on a golden stepping:
1) eBay – As long as care is taken to ensure a safe transaction (for example checking feedback and using a safe payment method) eBay is the perfect place to find a stepping for a cheap price. If the stepping of the CPU is not listed just send a message to the seller requesting the info.
2) Forums – The “For Sale” sections of forums often contain great steppings, along with pre-tested overclocking results for the CPU. Again, take care to avoid trolls who scam people.
3) Websites – Tankguys.biz is an example of a site which will allow you to pick a particular stepping as long as they are in stock. You will pay a little extra for this option, but unlike the 2 methods mentioned above you are guaranteed a safe transaction.
Finally…the top three AMD 3700+ steppings to look out for
If you can get your mitts on any one of the below steppings then you will most likely not be disappointed:
1) KACAE 0602GPMW
2) KAB3E 0547GPMW
3) KAB2E 0549EPDW
Conclusion
As you can see, the 3700+ San Diego is an amazing chip. However, remember that while steppings can be a good indicator of the potential overclocking performance, they are by no means a garauntee. We have assembled a thread of overclocking results for different 3700+ SD steppings on Overclock.net, you can find it here: http://www.overclock.net/amd-cpus/10...ners-past.html
This FAQ was co-written by Namrac and Rustynator. So if you're going to rep one of us, please rep both of us, as we did equal amounts of work creating this FAQ.
