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Does High-Speed DDR3 Help AMD's FX? Four 8 GB Kits, Reviewed

Does AMD-Optimized Memory Still Exist?

AMD has enjoyed the performance benefits of an integrated memory controller for more than twice as long as Intel. And yet, it seems that Intel sets today's standard for acceptability. When Core i7 (the Bloomfield version) launched with 1.65 V as its recommended maximum voltage, manufacturers divided their DDR3 DRAM across two product lines: higher-voltage AMD and lower-voltage Intel products.

Of course, appearances can deceive. When it comes to product development and (especially) marketing, this editor takes very little of what he sees at face value. Tom’s Hardware had already tested 1.50 V performance RAM many months before Intel’s original Core i7 launch, watched as manufacturers began making switching to smaller manufacturing processes (yielding less voltage-tolerant memory), and knew that DDR3 memory running at DDR2 voltage levels would soon be a thing of the past. Eventually, vendors with large inventories of older high-voltage ICs began marketing those sometimes-inferior products to enthusiasts with AMD CPUs because they could tolerate the abuse, all the while branding their new and improved products as Intel-optimized.


Memory must be bootable at motherboard-default voltage levels, defined by JEDEC as 1.50 V for DDR3 modules, in order to assure compatibility across multiple platforms. A tiny flash ROM (called an SPD) on each module tells the motherboard how fast (or slow) the memory needs to be configured in order to run at JEDEC-defined voltage.

The use of higher-than-standard voltage levels to reach higher performance levels is overclocking. So, most of what we refer to as performance memory is actually rated for overclocked settings.

EPP made memory overclocking easy, at least on many DDR2 platforms.

Many folks are simply too risk-adverse to start overclocking components manually. So, Corsair and Nvidia developed a method to do it semi-automatically. Released upon the world for all to play with, Enhanced Performance Profiles were memory configuration tables added to a slightly higher-capacity version of the SPD ROM. With this technology enabled, users could pick a complete memory overclock in BIOS. Since EPP was co-developed by former chipset manufacturer Nvidia, most of the motherboards that supported it had Nvidia chipsets.

A bad EPP 2.0 reading for 1.80 V RAM, taken from an XMP-specific motherboard.

But that was back in the days of DDR2. When Intel came out with a similar technology called eXtreme Memory Profiles for DDR3, the new technology was quickly added to user-configurable Intel-chipset motherboards. Corsair countered with EPP 2.0 for DDR3, but Intel’s dominance over its own platforms meant that the newer, lower-voltage Intel-oriented RAM shipped exclusively with XMP.

Aeneon’s attempt to combine EPP 2.0 and XMP on the same modules.

EPP 2.0 disappeared as supplies of the older high-voltage memory dwindled, and AMD-specific memory disappeared with it. All of today’s test modules have XMP profiles, and those profiles are displayed (but not selectable) in our motherboard’s firmware.