Quad-Channel Memory | PCIe | LGA2011
Quad-Channel Memory
One of the more hip features of the X79 / SBE and IBE platform is quad-channel memory. Back in 2008 we already reported that the initial Nehalem architecture was quad-channel ready, they just had never implemented it. But with triple-channel performance as good as it is on X58 it was remained thinking. Until X79 arrived. Intel's 64-bit memory controllers rock hard and a lot certainly happened. Over the space of four years we went from dual-channel towards triple-channel on X58 (Gulftown), then back to dual-channel with the Sandy/Ivy Bridge and Haswell architecture and with Sandy Bridge-E and Ivy Bridge-E we get quad-channel memory support. Regardless of what you think about it, progress is obviously always a good thing.
Admittedly, the Intel memory controller, whatever platform you choose, is excellent. Sandy & Ivy Bridge and its dual-channel controller hauls ass, make no mistake there. At launch for IBE quad-channel 1866 MHz low-voltage DDR3 is supported out of the box, and that means an increase from 29.9 GB/s to 59.7 GB/s of available memory bandwidth. That's fast enough to drive a mid-range graphics card ported through system memory fairly well, well if we exclude latency of course. Quad-channel is fun stuff, crazy numbers is what you'll see. What the effect will be on real-world performance, well that's trivial at best.
PCIe Lanes
The one thing that people grumble about the most is the relatively small number of available PCIe lanes (16) for graphics cards. If you are using a setup with two or more graphics cards (SLI/Crossfire), the PCIe bandwidth is limited at x8:x8. Here again the performance difference is trivial as running today's fastest cards barely utilizes all that bandwidth, but two x16 and then room for another x8 obviously is much better. Ivy Bridge-E has a cool 40 lanes available. You can split them up in a variety of combinations, two x16 links with one x8 link, one x16 link and three x8 links, or one x16 link, two x8 links, and two x4 links. So this will be one concern less, though I betcha some of you would like to see three x16 as an option.
PCIe Gen 3.0
Partially supported in Sandy Bridge-E but now fully supported with Ivy bridge E is the inclusion of PCI Express Gen 3. In a nutshell, PCI Express Gen 3 provides a 2X faster transfer rate than the previous generation, this delivers capabilities for next generation extreme gaming solutions. PCI Express Gen 3 has twice the available bandwidth, 32GB/s, improved efficiency and compatibility and as such it will offer better performance for current and next gen PCI Express cards. Going from PCIe Gen 2 to Gen 3 doubles the bandwidth available to the add-on cards installed, from 500MB/s per lane to 1GB/s per lane. So a Gen 3 PCI Express x16 slot is capable of offering 16GB/s (or 128Gbit/s) of bandwidth in each direction. That results in 32GB/sec bi-directional bandwidth.
LGA 2011
Over the last three years we left LGA 775 then started with LGA 1366, then moved to LGA 1156, with Sandy and Ivy Bridge we moved to LGA 1155. Fortunately Ivy bridge-E can stick to socket LGA 2011, just like Sandy Bridge-E. At the time of Sandy Bridge-E it was unfortunate, but with a changed architecture and features like the quad-channel memory controller, the lack of an embedded graphics unit and the massive update towards 40 PCIe lanes the entire dynamic changed. But sure, ever since 2008 that's four different CPU sockets in the mainstream desktop PC consumer market. For an Ivy Bridge-E processor you'll need to purchase an accompanying motherboard based on the X79 chipset. Not just that though, the cooler mount is completely different as well, you'll need to seek a new mounting bracket for your cooler, or purchase an LGA 2011 compatible cooler.
