[svlug] Question about RD Ram Hardware/Dell

[Mark C. Langston]

On Wed, Oct 30, 2002 at 11:41:40AM -0800, James Leone wrote:
> Hi lists,
> 
> 
> I have a coworker that owns a pentium iv Dell at home with a dual rim. 
> It came with 128 MB RDRAM x2 and AFAWK it should work in pairs. He 
> recently ordered some  256 MB RD RAM to add to the two additional open 
> slots, the only difference being the 128 v 256 MB and the fact that one 
> set of chips  are ECC while the others are not. He did buy Dell RAM chips.
> 
> It didn't seem to work after the chips were installed.
> 
> Could this be a hardware problem?
> 
> Is there a special procedure he has to follow to get them to work?
> 
> If it is a compatability issue, any suggestions on how he could get his 
> money back?


I recently switched from AMD to a P4 RDRAM system, so this may or may
not be entirely accurate.  

First, check to make sure the RDRAM he purchased is 16-bit, not 32-bit.
32-bit RDRAM is designed to be installed singly rather than in pairs,
and will only work on motherboards that support 32-bit RDRAM.  As far as
I know, the only one that does is the ASUS P4T533.

Second, try using the motherboard with _just_ the two new sticks of
RDRAM.  Recently there have been some problems with at least one
vendor's supply of 256MB 16-bit PC1066 RDRAM (Kingston), and they had to
recall a small set of batches.

Third, make sure that ECC is turned off in the BIOS.

Fourth, make sure that the RDRAM he already had and the RDRAM he jsut
purchased matches in speed.  There are two speeds of RDRAM:  PC800 and
PC1066 (aka 3x and 4x).  The BIOS must be set to the slowest of the two
if you're mixing PC800 and PC1066.  He may have had PC1066 (and thus his
BIOS is set accordingly), but he may have bought PC800, which -- though
it _might_ run at PC1066 speeds -- would probably fail.

That said, he may have mixed RDRAM vendors, which is not always a good
idea.  RDRAM is rather picky due to the extremely high bus speeds, and
depending on the motherboard, the variability of the bus voltage -- some
are less reliable than others.  (Dell doesn't make RDRAM.  They resell
one or more vendors' RDRAM -- typically Kingston, Crucial, and Samsung.)

Finally, more specificity regarding how "it didn't seem to work" would
help.  Perhaps it's running jsut fine, but not acknowledging the new
RAM.  In which case, it probably just needs to be reseated.


-- 
Mark C. Langston                                         Sr. SysAdmin
mark at bitshift.org                                     Project Phoenix
Systems & Network Admin                                SETI Institute
http://bitshift.org                                     mark at seti.org