D850EMVR motherboard: only 1.5GB PC1066 RAM. Why?

Hello,

I know, this is a pretty outdated consideration now, but could
somebody explain why is the total amount of memory the D850EMVR
desktop board can accept dependent on memory speed?

Indeed, from this page http://www.intel.com/support/motherb.../cs-010572.htm,
the D850EMVR desktop board can accommodate up to 2GB RAM using
PC800-40 RAMBUS modules, but only 1.5GB using faster PC1066-32
modules. What's the reason behind that? Hardware? Software (BIOS,
NVRAM)? Ethical?

BTW, does anybody tried to put 2GB PC1066 memory into a D850EMVR
desktop board? What happens then? No boot at all? Boot to OS but only
1.5GB seen by system? Boot to OS with 2GB seen by system but only
1.5GB usable by OS?

Thanks for sharing knowkedge,

Emeric

"Émeric" <> wrote in message
news:955ec94b-3709-4c56-be94-...
> Hello,
>
> I know, this is a pretty outdated consideration now, but could
> somebody explain why is the total amount of memory the D850EMVR
> desktop board can accept dependent on memory speed?
>
> Indeed, from this page
> http://www.intel.com/support/motherb.../cs-010572.htm,
> the D850EMVR desktop board can accommodate up to 2GB RAM using
> PC800-40 RAMBUS modules, but only 1.5GB using faster PC1066-32
> modules. What's the reason behind that? Hardware? Software (BIOS,
> NVRAM)? Ethical?

It's a hardware limitation. If you try putting in the 1066 memory,
it may not boot at all (most likely) or you may get mysterious errors
and corrupted data (not good!)

Tom Lake

> It's a hardware limitation. *If you try putting in the 1066 memory,
> it may not boot at all (most likely) or you may get mysterious errors
> and corrupted data (not good!)

When you say "If you try putting in the 1066 memory, it may not boot
at all", do you mean the extra 512MB RAM to reach the theoretical 2GB
limit? I'm talking about the D850EMVR version of the motherboard (that
has been validated for PC1066), not the D850EMV2 flavour.

The point I miss is, if the 850E chipset is able to recognize up to
2GB RAM, what prevents it from recognizing this amount of memory
independently of the memory type (PC800 or PC1066)?

> The point I miss is, if the 850E chipset is able to recognize up to
> 2GB RAM, what prevents it from recognizing this amount of memory
> independently of the memory type (PC800 or PC1066)?

It can't refresh 2 GB memory fast enough to use the higher speed RAM.
Think of a juggler who can juggle 4 balls at a high rate of speed.
Now give him 8 balls. He might not be able to keep up the same speed.
Give him 16 balls and his speed falls further. Sure he can juggle a few
balls fast but not too many. It's a very crude analogy but it works.
This particular chipset can only process a certain amount
of memory in a given time. If it only has 1 GB, it can use the faster
speed.
At 2 GB, though, it can only use the lower speed.

Tom Lake

Hello Tom,

> It can't refresh 2 GB memory fast enough to use the higher speed RAM.
> Think of a juggler who can juggle 4 balls at a high rate of speed.
> Now give him 8 balls. *He might not be able to keep up the same speed.

The juggler analogy was perfect.
Thanks for explaining.

Emeric

The best way of knowing what happens is to test it, try it and get tha nail out of your head... I am sure this wouldnt harm the board or the memorys making them unusable. System might just crash show a bsod and end of the story. I was thinking that an aproppiate aftermarket heatsink for the Northbridge would do the trick. If overclocking is allowed on an ASUS P4T533-C with 2Gb of PC800 (and this is the same "juggler") probably he is not feeling confortable an needs some refreshment. Let us know the outcome, I am a rdram board fan.