Intel Core-i7 3960X, X79 Express and LGA 2011 (page 18: Conclusion)

Conclusion

Intel has driven home its advantage with the release of the Core i7-3960X, which is now the fastest desktop processor on the market. As long as an application correctly exploits the six cores at its disposal, there's no competition for this processor and it offers excellent DDR3 support with up to 64 GB on four channels, allowing it to give previously unseen throughput. Of course, it’s also exorbitantly priced at $990 but the 3930K, which is only 3-4% slower, costs $550, which is a good deal more reasonable.

Of course, not all applications are able to put all the real estate to good use. As usual, creative applications are most able to do so, while games generally struggle to use four cores. For purely gaming use then, the Core i7 LGA 2011s don’t really offer much of an advantage over the Core i7 and i5 LGA 1155s, except for the fact that the platform is better adapted to multi-GPU configurations, particularly 3-way SLI / CrossFireX. This is a pretty modest advantage overall though as you can get LGA 1155 motherboards that use NVIDIA or LucidLogix PCI-Express switches which compensate for a good proportion of the limitations inherent to the platform.

In spite of the impressive level of performance given on LGA 2011, there were also a few disappointments. The first is that the overall gain is limited (around 15%) in comparison to the hexacore Core-i7s, the Gulftowns, which were released eighteen months ago. It has to be said that as both CPUs use a 32nm manufacturing process, Intel could only bring architectural (Sandy Bridge) or platform (quad channel DDR3) advances to bear at an equivalent thermal envelope. With respect to the platform, note the integration of the northbridge on the CPU here, a simplification in comparison to LGA 1366 which has a significant impact on energy consumption at idle.

The second disappointment is linked to the question of the thermal envelope, as Intel has really only done the minimum here. In effect Sandy Bridge-E is an 8-core but only six are enabled on the Core i7 so as to keep within a TDP of 135 Watts at decent clocks, with the last two cores being reserved for the Xeon E5s which will cost more. At $990, we might be forgiven for expecting a truly Extreme version; ie. with all eight cores enabled even if the TDP were to go up to 165 Watts!

The X79 Express platform also suffers from the same sort of restraint, though it seems that this may have been linked to a last minute bug rather than yet more Intel segmentation. Although the X79 Express was initially designed to support 4 SATA 3G, 2 SATA 6G and 4 SAS/SATA 6G ports, the SAS/SATA 6G capability has been removed and the X79 Express is now on a par with an H67/P67/Z68 Express LGA 1155, namely with 4 SATA 3G and 2 SATA 6G. Of course this is enough for the vast majority of users but given the very high-end positioning of the platform, with motherboards starting at €200 and going up to €350, Intel has missed out on the opportunity to extend the advantage over LGA 1155.

As you can see, this new platform has left us wanting more. Without any real competition from AMD at this level, Intel is far from having pushed the LGA 2011 platform to its limits. It does however offer by far the highest performance solution currently available as long as your application is highly multithreaded or you do instensive multitasking. Otherwise, LGA 1155 will not be too far behind and offers a much better price / performance ratio and better energy efficiency.

There remains a final unknown with respect to LGA 2011, which is how long a lifespan the platform will have. Will it last for some time like LGA 1366 or is it simply another short-lived socket like the now infamous LGA 1156? While current LGA 1155 motherboards will accept the forthcoming Ivy Bridge 22nm quad cores, there is as yet no certainty with respect to any Ivy Bridge-E 22nms that are released and likely to be compatible with LGA 2011 motherboards. If this were to be the case, the reduction in energy consumption linked to the 22nm engraving could well allow Intel to launch its first 8-core CPU in the Core i7 range!