AMD Divulges Phenom II X6 Secrets,

Turbo Core Enabled

Last month Intel introduced its first desktop 6-core CPU, the 32nm Gulftown Core i7 980X. Running at 3.33GHz we loved the fact that it’s quite possibly the first Extreme Edition part that is able to justify its price. For $999 you get six cores and better performance all in the same power envelope as the current high end quad-core i7s.

The 980X is a great chip, but spending $999 on a single component in your PC is a tough sell for most folks. Luckily, AMD is coming out with its own 6-core processors codenamed Thuban. Below is what we know so far about AMD's Thuban lineup (note, the information in the table was not provided by AMD):

AMD 2010 Roadmap
CPU	Clock Speed	Max Turbo (<= 3 cores)	L3 Cache	TDP	Release
Phenom II X6 1090T	3.2GHz	3.6GHz	6MB	125W	Q2
Phenom II X6 1075T	3.0GHz	3.5GHz	6MB	125W	Q3
Phenom II X6 1055T	2.8GHz	3.3GHz	6MB	125W/95W	Q2
Phenom II X6 1035T	2.6GHz	3.1GHz	6MB	95W	Q2
Phenom II X4 960T	3.0GHz	3.4GHz	6MB	95W	Q2

Officially branded the Phenom II X6, AMD won’t be launching these processors until some time in the future. But today AMD is disclosing some basic details about the parts. We’re also mixing in our knowledge of internal AMD roadmaps to paint a clear picture of AMD’s 6-core strategy.

The more cores at the same TDP feature that Intel delivers with the 980X, AMD is also promising with Phenom II X6. The difference is that these are still 45nm parts. While we’ll have to test them to be sure, AMD currently indicates that the entire Phenom II X6 lineup will be rated at 95W or 125W TDPs. It’s all manufacturing tricks that make it possible (good job GlobalFoundries). In theory you should be able to buy a Phenom II X6 and have it operate in the same power envelope as a Phenom II X4 965.

With the Thuban cores AMD is introducing its version of Intel’s Turbo Boost technology called Turbo Core. AMD has yet to implement power gating on its processors, so Turbo Core works a little differently than Intel’s Turbo.

Turbo Core kicks in when 3 or more cores (on a 6-core part) are idle. When this happens, the frequency of those three cores is reduced to 800MHz, the voltage to the entire chip is increased, and the remaining three cores are turboed up by as much as 500MHz. It doesn’t get any more granular than this. If you have 3 or more cores idle, then the remaining turbo up. In any other situation the CPU runs at its normal clocks.

The CPU handles all monitoring and does the clock/voltage management itself. The switch to turbo up cores apparently happens fast enough to deal with Windows moving threads around from core to core.

Turbo core is triggered by a deterministic system that is based on load demand and current operating conditions (not temperature).

Cool’n’Quiet is active throughout the turbo process. What actually happens is that when CnQ looks to see if a set of cores should be downclocked, it also has the ability to increase the frequency of other cores.

This isn’t nearly as elegant of a solution as Intel’s turbo. The idle cores are never actually shut off, and voltage to all cores is increased to reach the higher clock speed. However if it works as advertised with no drawbacks (e.g. underclocking 3 cores when you actually still need them) then it’s definitely better than nothing for the Phenom II lineup. AMD will also have quad-core CPUs with turbo core support based on the new Thuban cores.

The great news? All Socket-AM3 and AM2+ motherboards will work with these new Phenom II X6 CPUs with nothing more than a BIOS update. The boards do have to support the TDPs the chips are rated for of course.