The Same, But Different?
We started getting email announcements of a new generation of LGA 1155-compatible RAM right around the same time as details of Intel's second-gen Core processors surfaced. The funny thing was that Intel’s memory requirements didn't change from Nehalem/Westmere to Sandy Bridge.
The former platform’s documented maximum 1.575 V limit remains, with the same wink-and-a-nod from engineers that up to 1.65 V is safe. Indeed, the memory controller built into Intel's new processors remained substantially similar to that of its predecessor. But as it turns out, the introduction of new kits wasn't entirely marketing hype!
All of Intel’s DDR3 memory ratios correspond to data rate multiples of 266.6 MHz, including officially-supported data rates (DDR3-800, DDR3-1066, and DDR3-1333) as well as unofficial overclocked ratios (DDR3-1600, DDR3-1866, and DDR3-2133). Yet, many of the memory kits designed for LGA 1156-based platforms included oddball ratings like DDR3-2000 and DDR3-2200. In order to achieve DDR3-2000 without overclocking the CPU core, the builder had to set the appropriate ratio for DDR3-1866, raise the base clock by 7.2%, and then reduce the CPU multiplier by 7.2%. With 7.2% multipliers and non-integer base clocks unavailable, an approximation had to be made. Some memory manufacturers even abused Intel’s XMP technology in an effort to tell motherboards how to set these approximations automatically, though the builder still had to choose the appropriate XMP profile in the BIOS.
Intel’s new platform does allow fractional base clock increases, but, as we all know by now, does not support the aggressive base clock adjustments enabled by previous platforms. An increase of 7.2%, for example, is easy to set, but it's usually unstable. By significantly limiting the range of accessible base clock adjustments, Intel invalidated memory ratings that didn’t correspond to appropriate ratios. We interviewed several memory manufacturers at CES and confirmed that transforming LGA 1156-specific memory kits into LGA 1155-oriented models required nothing more than a proper name, and proper SPD and XMP values.
For instance, yesterday's DDR3-2000 becomes DDR3-1866, occasionally at lower latency ratings to help offset the sacrificed data rate. Later, as many builders reported no performance gains or even compromises in stability from increasing the controller's voltage from 1.60 to 1.65 Vs, at least one manufacturer responded by dropping its maximum rating to 1.60 V.
The hardware itself didn’t change; just the labels (both internal and external). That’s fine with us though, since a lot of the memory out there is already high-quality stuff. Even still, we'll still put it through the wringer in order to determine how far it can be pushed using Intel's new platform. Before we move on to specifics, let’s take a quick look at what these manufacturers have to say about their products.
|8 GB Dual-Channel DDR3 Rated Timings and Voltage|
|Corsair Vengeance CMZ8GX3M2A1600C9||1600||9-9-9-24||1.50 V|
|Crucial Ballistix BL2KIT51264FN2001||2000||9-10-9-24||1.65 V|
|G.Skill Ripjaws X F3-12800CL7D-8GBXH||1600||7-8-7-24||1.60 V|
|Geil Evo Two GET38GB2200C9ADC||2200||9-11-9-28||1.65 V|
|Kingston HyperX T1 KHX1600C9D3T1K2/8GX||1600||9-9-9-27||1.65 V|
|Patriot Viper Xtreme PXD38G1866ELK||1866||9-11-9-27||1.65 V|
|PNY Optima MD8192KD3-1333||1333||9-9-9-24||1.50 V|
|PQI Immortality Turbo MFAFR602SA7001||2000||9-11-9-27||1.65 V|
Note that several manufacturers have not yet updated their product portfolios, sending LGA 1156-rated parts for our LGA 1155 platform. Crucial specifically mentioned that it will most likely give these modules a new DDR3-1866 rating (and corresponding model number) in response to LGA 1155’s tighter BCLK limits, while several Geil press partners have mentioned “DDR3-2133” in regards to its DDR3-2200-rated parts. Launched last June for Intel’s previous platform, PQI is confident that its Immortality Edition Turbo D3-2000 will excel under the new platform’s limitations.