Intel pushes workhorse Xeons to six cores

Banging heads against the thermal wall

There are a couple of things to notice about the Xeon 5600 lineup. First, while Intel is offering four-core variants of the chips with slight clock speed advantages, those extra clocks presumably do not give all that much extra performance. That a Xeon X5677 with four cores sharing that 12MB L3 cache, or 3MB per core, runs at 3.46GHz, compared to a six core X5680 (with only 2MB of cache per core) running at 3.33GHz illustrates why all chip makers have hit the thermal wall and have little choice but to increase core counts and hope that virtualization and workload consolidation put off the day of reckoning that is surely coming when programmers cannot make use of the extra cores and threads in a chip.

As with the Nehalem-EP chips a year ago, the Westmere-EP chips includes a single-core workstation and server part rated at 130 watts (the W3680) and low-wattage parts. The Nehalem-EPs had standard parts that burned at 80 watts or 95 watts, plus one 130 watt part and two low-voltage parts with four cores that burned only 60 watts. With the Westmere-EPs, the two 130 watt parts are now standard server parts, with the X designation, not the W designation meaning workstations only.

There are similarly 95 watt and 80 watt Westmere-EPs with four or six cores as well as the entry-level Nehalem-EP parts with two or four cores that are still in the lineup for two-socket machines. With the Westmere-EPs, there is one 60 watt part, the L5640, that has all six cores fired up that runs at 2.26 GHz, and a four-core L5630 with only four cores running at 2.13 GHz that is rated at 40 watts. The even cheaper L5609 chip, also a 40 watter with four cores, doesn't have TurboBoost, HyperThreading, AES, or TXT activated, and runs at 1.86 GHz.

Boyd said in the call that the pricing for the Xeon 5600 processors was roughly the same as what Intel is charging for an equivalent clock speed and feature set (minus the cores and cache, of course) in the Xeon 5500 line. This is not precisely true. Intel is most definitely charging a slight premium for some Xeon 5600s, and is no doubt justified in doing so based on the multithreaded performance that the chips offer - somewhere between 20 and 63 per cent on various HPC workloads and roughly 40 per cent for more mainstream infrastructure workloads running predominantly on Windows and Linux operating systems. Some Xeon 5600s - those that have only four cores - are cheaper than their Xeon 5500 counterparts.

Let's take the top-end parts. A four-core Nehalem-EP W5590 running at 3.33GHz costs $1,600, but the X5680 running at the same clock speed with six cores costs $1,663, a 3.9 per cent premium. (The four-core Westmere-EP X5677 with only four cores turned on and running at 3.46GHz costs the same $1,663.) The mainstream high-end four-core Nehalem-EP part in the 95 watt power band is the X5570, which spins at 2.93GHz and which costs $1,386. The X5670 has six cores and costs $1,440 - again a 3.9 per cent premium. The top-bin 80 watt part in the Nehalem-EP lineup was the E5540, running at 2.53GHz and costing $744; the equivalent Westmere-EP part, the X5650, spins at a slightly higher 2.66GHz and costs $774, which is a 4 per cent premium for 5.1 per cent faster clocks. (Seems reasonable.) The four-core Westmere-EPs known as the E5630 (2.53GHz) and E5620 (2.4GHz) have all the extra goodies on them and cost $551 and $387, respectively; the most similar 80 watt Nehalem-EP parts, the E5540 and E5530, cost $744 and $530, respectively. So basically, Intel has shifted the prices for these processors down one bin level with some wiggling.

Another thing to notice from the table above: the six-core E5645 and L5638 as well as the quad-core L5618 and E5620 processors are designated as enterprise-class embedded processors, which are aimed at thermally constrained physical environments. Intel is promising to sell these processors for seven years to get embedded system makers to adopt them in their products.

Intel is also chasing the micro-server segment and has pumped out a two-core, four-thread Xeon L3406 processor, which runs at 2.26GHz and is rated at 30 watts. It costs a mere $189 a pop if you buy them in 1,000-unit trays.

Finally, Intel is also delivering the Core i7-980X Extreme Edition processor, which the company has been showing off to the gaming community. The i7-980X sports six cores running at 3.33GHz and plunks into existing machines that use the Intel X58 Express chipset. It costs $999 each in 1,000-unit quantities. ®