At 08:38 08/25/00, John <[log in to unmask]> wrote:
>At 00:56 08/25/00, jeffrey <[log in to unmask]> wrote:
> > One thing that immediately raised red flags for me is the use of 4
> > clock, CAS3 PC133 memory in two (not three) DIMM memory slots.
> >
> > What gives here ???
> >
> > I had expected support for high-performance 2 clock, CAS2 PC133 memory
> > and > timing, such as is offered in any good 440BX-based mainboard
> > system.
> >
> > Is this a configuration that has been built by design to inhibit the
> > system's performance potential ???  Or is this a way of dealing with
> > unresolved (perhaps unresolvable) stabilty issues ???
>
>I don't know which mb Dell is using, but the i815e supports PC133 SDRAM,
>including CAS2. It is limited to only supporting 512mb of SDRAM, and
>this probably does reflect an effort on intel's part to keep this
>chipset aimed at the personal computer market and not have it infringe
>on the server market.
>
>I have heard about some complaints about some memory modules not working
>well with the 815e, but these complaints seem to be sporadic and without
>a clear pattern as to which memory is best or which memory to avoid.
>
>I noticed that you referenced AnandTech's site; you might want to browse
>their motherboard forum and see what folks are saying about this new
>product.


According to AnandTech in his discussion on the 815/815E chipsets,
"while the i82815 GMCH [Graphics and Memory Controller Hub] supports
6 rows of memory, enough for 3 DIMM slots, Intel has only qualified
it to support 2 PC133 DIMM's at once. In a board that follows Intel's
specs, as soon as you drop in a 3rd DIMM, the board will fall back to
PC100 operation. Fortunately for us, motherboard manufacturer's
know we like to tweak our systems, and many boards will allow setting
the memory speed manually. Yet another sign of "artificial" limitations
by Intel? In this case we did notice a drop in stability with many boards
when running 3 DIMM's at 133 MHz. Our test system would experience random
lockups and would fail to complete some tests."

So for motherboard makers to allow use of 3 PC133 DIMMs (which is beyond
specification for the 815 chipset), they might have to slow down the
memory timing in some way...possibly by limiting you to use of CAS3
memory.

By the way, both i815 and i815E use the same memory controller hub. The
main differences between i815 and i815E are that the i815E adds support
for Ultra ATA/100 (instead of ATA/66) and has two more USB ports.

Regards,
Bill

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