<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: Arial; font-size: 12pt; color: #000000'><br><br><br><br>>----- Original Message -----<br>>From: "Mark Hahn" <hahn@mcmaster.ca><br>>To: "richard walsh" <richard.walsh@comcast.net><br>>Cc: "Beowulf Mailing List" <beowulf@beowulf.org><br>>Sent: Wednesday, May 13, 2009 12:35:47 AM GMT -06:00 US/Canada Central<br>>Subject: Re: [Beowulf] recommendations for cluster upgrades<br>><br>>> on-chip Power Control Unit that actively manages idle and active power<br>>> consumption is a dramatic leap forward for Intel in this space,<br>><br>>i7's memory improvements are pretty clear, but I haven't seen<br>>reviews that show too much benefit/advantage in power management ...<br><div><br></div><div>Yes, more work needs to be done to determine the quality and quantity</div><div>of benefit. I do think increasing the number of core power states (including</div><div>a complete power off state), offering core-independent power management,</div><div>and the ability to up-clock some cores while downing others allows for</div><div>much finer dynamic control of power use. This is of course being done at</div><div>45 nm too. It's early and the implied benefits on systems that are running</div><div>flat-out most or all of the time, which is the objective the objective of HPC</div><div>workload managers may be limited. Better benchmarks are needed as</div><div>well.</div><div><br></div><div>The two lines that you extracted from my message imply that I think the</div><div>PCU by itself is a "dramatic leap forward for Intel." This was not my </div><div>intent. Nehalem in total is however ... even if it largely adopts the design</div><div>standards AMD introduced 3 or 4 years ago.</div><div><br></div><div>Regards,</div><div><br></div><div>rbw</div></div></body></html>