Intel Bensley Platform Preview
Posted on: 11/07/2005 06:00 AM

Power Consumption

Since all of the big names are really focusing on "performance-per-watt" these days, I figured that I should probably jump on the bandwagon too. I was really interested to see how the power consumption would compare across the three test machines. Nocona Xeons have a TDP of 110w, Dempsey has a TDP of 130w. Hell, even my old original Opteron 246s have a TDP of 90w!

Unfortunately, as of this writing UPS still has my Kill A WATT meter on a truck. At least now it is somewhere in Ohio, scheduled for delivery sometime today (November 8, 2005). Rest assured, I'll update this section just as soon as I can.

*UPDATED* - 11/09/2005

I got the Kill A WATT meter last night and ran some quick tests. It should be noted that the number of fans in each machine was different, as well as the power supply rated wattage. To give a brief rundown...

Opteron: This machine has 3x 92mm fans, two fans on the heatsinks and a PC Power & Cooling 510W PSU.

Lindenhurst: The dual 3.8ghz Xeon has a total of 3x 80mm fans, 2x 92mm fans and dual redundant 760W PSUs (only one of which was plugged-in).

Bensley: The Bensley box has three 120mm fans, two fans on the heatsinks and a 700W PSU.

If the machines had power saving settings in the BIOS, I enabled them. Isn't that what they're there for? The idle readings were taken with the machine booted into Windows, sitting idle at the desktop. To load the machines I fired-up the Black & Scholes benchmark with the appropriate number of threads for the machine.

All readings presented are the highest observed over the test periods (both idle and load).

Wow. The Xeons draw some serious power. Considering the added processing power you get from Bensley (over the Lindenhurst machine), the additional wattage doesn't seem too out of hand. Then again, I definitely couldn't imagine what the power bill would be like to maintain a whole server room full of those monsters.

I could either leave these machines running on my test bench, or I could leave every single light on in my house 24/7.


So what have we learned in all of this? Paxville was not very well received, but I think a lot of that was because everyone wanted to see how Dempsey would perform before making the leap. As we've seen on the last six pages, Dempsey is no slouch by any means. If you absolutely have to buy a new server in the next few months and, like me, you're limited to whatever Dell has to offer, I don't see any reason not to go the Dempsey route. With only slightly higher power (and heat) requirements than Nocona, the extra cores (and threads) and cache are well worth it.

As for Bensley as a platform: Intel has done a lot of work on the Blackford (and Greencreek) MCH. The memory bandwidth is up quite a bit compared to Irwindale, and we can see some definite advantages in real-world applications. Although still not on par with the on-die controller sported by AMD's Opteron, the additional memory bandwidth is quite an improvement over current Xeon platforms, and a much needed one.

While we're on the subject of memory, the addition of the FB-DIMM to the new Xeon line-up is an interesting one. Initially I was leary of the latency penalty of adding the buffer, but once I actually used the machine and ran the workloads my fears were gone. The bandwidth is there and the added features that FB-DIMMs bring to the table are certainly welcome in the server space. Some wondered if changing memory formats again so soon after the introduction of DDR2 was a good idea, but I think it looks like they did the right thing.

Probably the most interesting thing about Bensley though, is that by 2H06 we will get a drop-in replacement for Dempsey, Woodcrest. Woodcrest is the processor that a lot of people are waiting for as it takes the best of the current Netburst architecture, the best of the Pentium M architecture and throws in some tweaks and improvements to boot... All at a significantly lower TDP. With Bensley now, you can be sure you're ready for Woodcrest later.

I'm sure there are a lot of things that I left out of this preview. Some I'm sure I forgot, some I overlooked on purpose. I will revisit this all again once I have the shipping, retail version of the Bensley platform with all the features and a final BIOS. If you have any questions or comments, feel free to swing by our forums and make yourself heard.

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