Tuesday, May 16, 2006

A Secondary Serial Presence Detect - TRULY, LOL!

In a world where memory is supplied by billion dollar companies with billion dollar fabs, retail memory sales is dominated by ONE large company and many many smaller companies vie for the remainder of the sales, what does one of the smaller companies do to increase profits and get noticed?
  1. 1) Put a voltage probe on your memory module
  2. 2) Give fancy colored heat sinks for the RAM chips
  3. 3) Send more and more memory to the review sites
  4. 4) Sell fewer modules even, much more expensively
  5. 5) Put a secondary, more complete Serial Presence Detect table on the chip and get a big name to endorse it

6) All of the above

Well, Corsair has been around for a long time, and it has done all of the above. This entry deals with point #5. The Serial Presence Detect is a chip introduced a decade ago, storing information on the general properties of the memory module so if a computer does query the memory module on the settings it is capable of supporting, the SPD just dumps the table to the computer so that it can adjust its own settings to support the memory module optimally based on the settings put on the SPD.

Let's not talk about normal people. Normal people don't know what SPD is, they just put memory inside, and normal computers have their SPD detection set ON by default.

But Corsair is NOT peddling memory to normal people here. Normal people buy whatever is cheapest and it's normally Kingston. Look at the Techreport link - they're putting it on their TwinX premium modules. These modules are usually peddled to poseurs or enthusiasts.

Let's also not talk about poseurs. A poseur who buys a Tiptronic Porsche Turbo (a 996, because a 997 Turbo Tiptronic is faster than a Manual and thus may not ONLY be a Poseur Car) is at least more easy to understand (he can show it off, it's loud, and he can be seen coming outta it) than a Poseur who buys a memory module and puts it into his PC then seals it up. What good is it to a poseur if he can't show it off?

So, poseurs being dangerous territory, let's just discuss enthusiasts. REAL hardcore PC enthusiasts like Shamino of VR-zone.com or even Macci. Or any of the thousands of them who lurk in Anandtech and Hardwarezone in search of project ideas, and who get their minds and hands dirty with their projects.

Enthusiasts have long eschewed SPD. And rightly so. Because no memory company can afford the days spent in stability testing to find the true limits of a certain memory module in relation to a customized motherboard or rig set-up, so no SPD describes the limits of the memory modules. Each motherboard is different, their tolerances and design are different, even different firmware revisions for the same motherboards differ in their tolerance for memory, at its limits, so any SPD which settings even approach the true limits of its host memory module, may work for one motherboard but not for another. Each motherboard manufacturer makes compromises and judgement calls on setting the limits of their pathways, and tweak their BIOSes either to the way of sheer performance or compatibility. One can't have their cake and eat it, though a good designer can come damn close.

So, now nVidia and Corsair now have this thing called EPP or Enhanced Performance Profiles. Basically it's a secondary, more complete SPD, which include `signal drive strength settings, write recovery and active refresh settings, and delay and setup times'. First, I must commend nVidia. This is completely to their interest. It makes their chips easy to use.

But for Corsair, ... , well, it smacks of the poseur gearbox syndrome (again, think Porsche Tiptronic Poseur Gearbox). Firstly, no way in hell can Corsair test each chip to the limits. And no way they can guarantee that, after months of extreme use, their module will be able to sustain the same limits it exhibited when new. So, the SPD and EPP will all exhibit very conservative settings.

So it will definitely help the poseur crowd, but for the enthusiast, nothing has changed. As long as the automated SPD and EPP does not reach the limits, they eschew it, or SCREW it.

Still, this EPP should be valuable for the normal human being or the poseur crowd. Probably Kingston ValueRAM should implement it, at least the normal humans of the world can take advantage of slightly better performance on default settings.

BS scanner off. Ambigious result.