AMD近日公佈了下一代處理器架構推土機的大量技術細節，不過還有一個問好縈繞在很多人心頭：新架構是否會向Intel那樣頻頻更換新接口而導致無法向下兼容？
AMD桌面處理器目前的主力封裝接口為AM3，首選搭配AM3插座主板，而之前的AM2+插座主板通過更新BIOS也能支持AM3處理器，只是損失高速HT總線等新特性。
AMD的一位官方人士今天接受媒體採訪時確認：「現有的G34、C32服務器平台會支持基於推土機的新款服務器產品(英特拉格斯/巴倫西亞)。至於桌面上，為了充分發揮推土機架構的能力，會引入增強的AM3+接口，支持推土機並向下兼容現有AM3接口處理器。」
首款基於推土機架構的桌面處理器代號「贊比西河」，四個或八個核心，支持DDR3內存。按照AMD的說法，AM3+新接口處理器不能使用在目前的AM3插座主板上，但是現在的AM3接口處理器卻能用於未來的AM3+新插座主板。簡單地說，現在是新處理器可用於舊主板，今後是舊處理器可用於新主板。
這也就意味著：第一，AM3+處理器的針腳數會更多(AM3是938針、AM2+/AM2是940針)；第二，推土機架構仍是雙通道內存控制器，如何滿足八核心需要而不構成瓶頸、如何競爭Intel三通道乃至未來的四通道都是懸疑。
在去年底公佈的路線圖上，推土機處理器接口仍然標為AM3，AMD最初也考慮過沿用AM3接口，但是隨後意識到必須做出一個選擇，是繼續提供AM3而損失新架構的一些新特性，還是升級接口而帶來更好的功能和性能？最終為了長遠利益，AMD選擇了後者。
當然，我們(AMD)也可以同時製造AM3、AM3+兩種接口的新處理器，但這首先會大大提高成本，並推遲上市時間，還會引起市場混亂，其次兩套產品線會讓很多開發步驟所需要的時間加倍，而這正是我們(AMD)耽誤不起的。
AMD最後表示，對新產品最感興趣的應該是那些發燒友，他們不會屈尊於次等性能，推土機處理器最初的市場定位也在高端，所以AMD必須確保新架構能夠滿足高端玩家的性能和超頻需要，於是就有了AM3+。
Advanced Micro Devices said that its next-generation desktop processors code-named Zambezi will use socket AM3+ platforms, which will be backwards compatible with the firm's existing AM3 products. While the latter is an advantage for the platform, it may be a disadvantage for eight-core processors based on Bulldozer micro-architecture.
"The existing G34 and C32 server infrastructure will support the new Bulldozer-based server products. In order for AMD』s desktop offering to fully leverage the capabilities of Bulldozer, an enhanced AM3+ socket will be introduced that supports Bulldozer and is backward-compatible with our existing AM3 CPU offerings."
"When we initially set out on the path to Bulldozer we were hoping for AM3 compatibility, but further along the process we realized that we had a choice to make based on some of the features that we wanted to bring with Bulldozer. We could either provide AM3 support and lose some of the capabilities of the new Bulldozer architecture or, we could choose the AM3+ socket which would allow the Bulldozer-base Zambezi to have greater performance and capability.
The majority of the computer buying public will not upgrade their processors, but enthusiasts do. When we did the analysis it was clear that the customers who were most likely to upgrade an AM3 motherboard to a Bulldozer would want the features and capability that would only be delivered in the new AM3+ sockets. A classic Catch-22.
Why not do both you ask? Just make a second model that only works in AM3? First, because that would greatly increase the cost and infrastructure of bringing the product to market, which would drive up the cost of the product (for both AMD and its partners). Secondly, adding an additional product would double the time involved in many of the development steps.
So in the end, delivering an AM3 capability would bring you a less featured product that was more expensive and later to market. Instead we chose the path of the AM3+ socket, which is a path that we hope will bring you a better priced product, with greater performance and more features - on time.
When we looked at the market for AM3 upgrades, it was clear that the folks most interested in an AM3-based product were the enthusiasts. This is one set of customers that we know are not willing to settle for second best when it comes to performance, so we definitely needed to ensure that our new architecture would meet their demanding needs, for both high performance and overclockability. We believe they will see that in AM3+."
