EPP and SLI Memory
NVIDIA are set to support an extension of the SPD ROM in memory modules in their upcoming core logic, teaming up with memory vendors to do so and submitting the new spec to JEDEC, the governing body for computing memory standards.
Part of the soon-to-come nForce5 and branded by NVIDIA as SLI Memory, EPP extends the SPD concept, where the memory module contains readable configuration information so the memory controller can better work with it.
Whereas the SPD stores basic timing parameters and rated speeds, EPP goes some steps further, using the SPD ROM storage space and hijacking a 160 byte range in the ROM to store extra information. That information will include operating voltage, even more timing parameters and, most importantly for NVIDIA, what amounts to overclocking information.
With nForce5 tied to AMD's forthcoming Socket AM2 platform shift, which endows new 940-pin AMD processors with a DDR2 memory controller that supports DDR2-800 as an AMD-approved maximum speed, EPP will allow nForce5 to run EPP-supporting modules at faster than their rated speed, and faster than the DDR2-800 maximum officially supported by the CPU.
Effectively the module will say, "hey, while outwardly I'm DDR2-XX memory at this voltage and these timing parameters, if you overvolt a bit and relax these settings, I'll go even faster, and I fully support you configuring me to do so".
And yes, the overclocker has been investigating those limits and settings since overclocking began, but the difference is now the core logic, CPU and DDR2 DIMMs are all in on it and do the hard work for you, extending the simple data in the SPD ROM to do so.
A simple BIOS toggle is presented when the core logic reads the EPP space and finds correct information, allowing you to run at new 'SLI Memory' speeds on nForce5. If you remember what SLI stands for -- Scaleable Link Interface -- you can see how the acronym applies to pretty much any clocked interface in the system. We won't give the game away today, but look out for that theme occurring pretty much everywhere with nForce5 upon launch.
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The premuim they will charge for "SLI" memory is not gonna be insignificant.