System power
Barcelona is set to launch in August, with systems based around it shipping in September. This first round of processors will come in just two clock speeds - 2GHz with a 95W TDP and 1.9GHz with a 68W TDP.
These clock speeds may not sound overly impressive, especially given that quad-core Xeons can now be had at 3GHz. This is because AMD has chosen (or perhaps will only have the volume availability) to concentrate its efforts on the area that it says accounts for the majority of product shipments - the low and 'mainstream' power bands.
As a result, AMD's 95W parts should be seen as lining up against Intel's 80W quad-core Xeons and this brings the clock-speed differential down considerably. Intel's fastest 80W Clovertown clocks in at 2.33GHz.
Talking about comparing a 95W AMD part with an 80W Intel part may sound a little strange but it needs to be remembered that, unlike the AMD CPUs, Intel's do not integrate the memory controller. So, when you take the northbridge into account, AMD-based systems should consume less power overall. Additionally the FB-DIMMs of Intel's current Xeon platforms are notoriously power-hungry.
Working from AMD's comparison numbers, the AMB (Advanced Memory Buffer) built on to each FB-DIMM draws around 8W more at load than regular Registered DDR2-667. But, the optimal configuration for FB-DIMMs is at least four sticks of memory - to allow for quad-channel memory access - and that should balance out the power-usage equation.
Overall, we expect to see quad-core Opteron and Xeon server systems drawing similar amounts of power but with Opteron showing power savings as the number of memory modules increases.
