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A64 memory controller

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June 2, 2004 9:55:21 PM

You learn something new everyday at Toms. I for instance, just learned that the official specs on the A64 say that it can only support <b>1 double banked module</b> in any of its mem slots at 200FSB. All due credit to mobo and chipset manufacturers for allowing 2 double banked modules, but this whole thing sounds like a fiasco to me, and makes me once again doubt the viability of running 3 512 modules on my MSI K8N Neo Platinum when I get it. Point is, this seems really short sighted, making a processor that by its own admission grossly hampers itself when using a wide variety of legitimate (512X2 is pretty standard these days) memory configurations.

"The only way to overcome temptation is to yield to it" - Oscar Wilde

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June 2, 2004 10:48:59 PM

I would be inclined to agree, but MSI tech support assured me that if I used RAM off their qualified list, I could run 3. I'm actually very tempted to just run 2X512 Corsair XMS and say adieu to the whole fiasco, but I think 3X512 is more foward looking.

"The only way to overcome temptation is to yield to it" - Oscar Wilde
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June 2, 2004 10:58:23 PM

<A HREF="http://www.msi.com.tw/html/products/mainboard/testrepor..." target="_new">Here</A> is their memory compatibility testing guide. As you can see, there are several cases where 3X512 is supported at ddr400. Confusing, isn't it?

"The only way to overcome temptation is to yield to it" - Oscar Wilde
June 2, 2004 11:54:07 PM

anandtech also confirmed that the msi k8n neo platnium and chaintech vnf3 250 can run with all 3 dimms running at ddr 400. so yes it something you need to check on before buying a board.

it seems to me that this isnt so hard to be supported by mobo makers since amny of the makers offer boards that allow all 3 to be populated, so i dont feel very slighted by amd. i do think they let the mobo makers get lazy by making the low option of only one double sided dimm at 400, when its obvious its not that tough to make work and the cpu works fine with it.
June 3, 2004 1:23:54 AM

notice i said vnf3 250 not znf3 250, different boards
June 3, 2004 6:35:18 AM

I didn't think 1 double sided was the minimum that AMD allowed, I thought 1 double sided was the <b>published</b> maximum from AMD. In other words, I thought they designed the memory controller to only be able to support 1 double banked module at 400FSB. That seems short sighted.

"The only way to overcome temptation is to yield to it" - Oscar Wilde
June 3, 2004 6:40:47 AM

They allready had one update of the memory controller. The next stepping will probably see more improvements...

A long long time ago, but I can still remember, how that music used to make me smile... <A HREF="http://www.nexus.hu/zonix/DIGGER.MID" target="_new"><b><font color=blue>Digger rulz</font color=blue></b></A>
June 3, 2004 6:50:37 PM

i never said it was the minimum. AMD told makers that 1ds was the limit. But you can clearly see its works fine with even 3 ds dimms in some boards, so its not that the chip cant handle it, its that AMD told board makers to not try it. That was thier mistake, maybe it was just to cover thier bases return wise, but whatever the reasons, it doesnt appear to be that the part is difficent.
June 3, 2004 10:04:52 PM

> Point is, this seems really short sighted, making a
>processor that by its own admission grossly hampers itself
>when using a wide variety of legitimate (512X2 is pretty
>standard these days) memory configurations.

Well I disagree. AMD's specs are indeed quite conservative, but keep in mind even running just at 333 Mhz, memory latency is only a fraction of what it is using an external memory controller @400, and overall performance will still be better. You want to have the cake and eat it too. Well, I guess its nice some motherboards let you eat it too, just don't expect AMD to guarantee it.

Look at it this way; imagine you could buy A64 boards with an external memory controller, that would support 3 double sided dimms @400 Mhz, or you could buy other boards that use the ODMC with either single sided dimms @400 or DS @333. Which one would you pick ? I know which one would perform better.

BTW, the first option is perfectly possible. Someone could design an external memory controller for the A64 link it through HTT, but no one does, cause it doesnt bring you anything, even if it would support higher frequencies.

= The views stated herein are my personal views, and not necessarily the views of my wife. =
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