Intel D850EMV2 and PC800/1066 Problem

Hello all. I'm having a bit of a problem with my new mobo and chip. I have an Intel D850EMV2 and a P4 2.4 533mhz FSB. I have read on the web that the board doesn't officially support RDRAM 1066 but it does work with it. I installed the new board and chip with PC800 in the first two RIMM slots and the terms in slots 3 & 4. I updated the bios to the most current version and got my XP Pro loaded no problem. I then installed the PC1066 in the first two RIMM slots and tried to start the machine and it wouldn't even begin the POST let alone check my video card. So, on a hunch I reinstalled the PC800 in slots 3 & 4 and the machine started without a hitch and registered both the PC800 totalling 256mb and the PC1066 totalling 512mb. I pulled the PC800 out again and it froze on a black screen before the POST. I checked the bios settings and the FSB speed is 533mhz with the PC800 in alone and even mixed with the PC1066.

All the reviews I've read about the board have had PC1066 installed and worked no prob. I think it's weird it'll find the PC1066 when I have the PC800 in the other slots, no matter which comes first.

Can any of you shed light on this situation? I'm thoroughly confused. Thanks!
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  1. Your board DOES support PC1066, as I have the same board, running PC1066! You might have some faulty PC1066 though. You see, there was a lot of "PC1066" which actually used PC800-40 chips! Yes, this was a rip-off, memory overclocked by the module manufacturer.

    OK, my guess is that when you have both the PC1066 and PC800 mounted, the system runs all the memory at PC800 speed, and this "underclocking" of the "PC1066" is stabilizing it.

    You see, your board can run PC800 with a 533MHz FSB. The "4:3" CPU to RAM ratio allows this. And that gives you 533:400 CPU:RAM. What's more, I don't recall BIOS actually telling you what speed your MEMORY is running at, you'd have to use a third party program, such as a late revision of WCPUID.

    <font color=blue>Watts mean squat if you don't have quality!</font color=blue>
  2. Crashman,
    Right in the bios next to RAM it says what speed the RAM is, not what it's running at. I just used WCPUID and it said, 768mb at 397.7mhz. I guess you double that for the two 16bit modules?

    Anyway, I was just working and I got a memory error while using IE. I checked my event viewer and there were about 10 memory errors all at different offsets from the time I turned my computer on. What's going on? I think I'm gonna pull the PC1066 out and see if I get anymore errors.

    Thanks for your post. Any more ideas would be greatly appreciated.
  3. Not doubled because the modules are parallel, but doubled because RDRAM also used DDR technology. Yes, it's running PC800 speed.

    Now you have another problem. I believe the i850E chipset runs your PC800 with PC1066 timings (latency and so forth). This is why Intel said to only use PC800-40 (40ns instead of 45ns) with the 533 bus processors.

    So when you install the old modules, it makes the new modules run at a slower speed they are compatable with. But it also pushes the older modules over the edge. And with only the newer modules installed, you can't boot. My best guess (still) is that your PC1066 is not REAL PC1066, but instead overclocked PC800-40. And it's not working out for you. You should see if you can exchange it!

    I have the same board with Samsung PC1066 and it works fine and at PC1066 speed (533MHz RAM)!

    <font color=blue>Watts mean squat if you don't have quality!</font color=blue>
  4. You wouldn't happen to know the AA# off your board or the part number off your RAM would you? I know they came out with a D850EMVR that replaced the D850EMV2 that officially supports PC1066. I have Samsung Rambus #MR16R1628DFO-CT9 1066-32P. The AA# is on the board between the RAM slots. Also, I'd be curious to see what Bios version you have.
    Check these out...
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    <A HREF="" target="_new"></A>

    When I put the PC1066 in, I don't get any kind of warning. I actually don't get anything. I e-mailed the place I got the RAM from last night, I'm going to see what they say and then talk to Intel today. My only worry is, I'm running out of time to return the RAM. Thanks again.

    Crashman, one more thing. I just pulled the PC1066 out of my computer and really looked at it. There is a different number than the one on the heatsink at the end of the RAM. Could this mean that the RAM is overclocked? If you could pull yours and check, I would really appreciate it. The second number is actually imprinted on the RAM chip itself. Thanks again!

    <P ID="edit"><FONT SIZE=-1><EM>Edited by jcclow on 06/19/03 04:16 PM.</EM></FONT></P>
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