Nehalem Xeon L5530-based server power consumption

Low-powered Nehalem chips are great for servers.

With all the 'green' energy saving focus these days, it's no wonder that the GigaFLOPS and Gigabytes numbers are now joined by Watts figures too.

Except, in the case of Watts, the lower the better. The recent crop of high end workstation, server and desktop processors have both high performance and good power performance options. For instance, for the Nehalem-EP, the same D stepping design can be either a high powered W5590 3.33GHz processor with a 120W power envelope or an ultra low power L5530 2.4GHz processor with a 50W power envelope. So, 33 per cent more speed for 2.4 times higher TDP, but you have a choice depending on your needs. Both have the same large caches, three-channel memory per CPU and QPI links, but very different power and performance profiles.

Here we have a look at one such configuration. I put together two of these L5530 Nehalem Xeons on the Asus Z8NA-D6 mainboard, a very unique ATX-sized dual CPU mainboard with all six memory channels, one DIMM per channel. Now, with proper design tuning, that could really reduce the round-trip latencies on each channel. The mainboard is not a typical reference design, but reworked using solid capacitors and tighter traces to fit everything needed within the ATX format. Now, there are no extra bells and whistles that its Harpertown 5400 chipset predecessor, the Z7S-WS, had. Heat pipes on the chipset or overclocking features are not seen here at all, unfortunately. Nevertheless, the Z8NA-D6 mainboard, with its spread of features including on-board SAS with a hardware RAID option, does impress. And, oh yes, it accepts desktop memory without problems.

Speaking of the memory, I also used the Geil very low voltage DDR3 memory that we tested before on the Gigabyte X58 and P55 platforms. Its DRAM sticks are officially declared as 1.3 volts but run fine at 1.2 volts. With the Asus Z8 mainboard option to force 1.2V memory in hardware, it was a piece of cake. The memory ran and passed all tests at 1.2 volts, including Sandra benchmarks, Linpack and 3DMark Vantage. It would be interesting if Geil was to put out an ECC version of this memory.