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To: hmaly who wrote (79697)5/8/2002 9:51:16 AM
From: Joe NYCRead Replies (1) | Respond to of 275872
 
Harry,

As you can conclude on your own by looking at the necessary math, there isn't a single Pentium 4 DDR solution available today that can offer the amount of bandwidth necessary to feed a 4.26GB/s 533MHz FSB.

True, not today because all that's available are single DDR channel chipsets. This will change, and between Q4 2002 and Q2 2003, Sis, Via and Intel will all have dual channel DDR chipsets.

Joe



To: hmaly who wrote (79697)5/8/2002 3:56:19 PM
From: Ali ChenRead Replies (3) | Respond to of 275872
 
"According to who? Not to Anand. Read this part."

Why should anyone read this blurb? There is
no such thing as "necessary bandwidth it feed a xxxGHz"
processors, any bandwidth is not enough since times
when CPU core speeds started to exceed the
multi-cycle memory access time.

What is more important wrt Rambus is that the 533/PC1066
has not delivered anything close to what was expected.
For truly scalable memory the SPEC scores for a 2533 NW
processor must be at 930/950 level, yet Intel reported
only 830-860 range in their PR. Also, if you look
at www6.tomshardware.com

the system with PC800 in several cases OUTPERFORMS
the PC1066 system:
MPEG4:
2400/133/400 = 35.55 fps,
2400/133/533 = 35.18 fps
( www6.tomshardware.com )

MPEG2 with the same result.

In 3D Studio Max 4.3,
www6.tomshardware.com
2400/133/PC800 and 2400/133/PC1066 are equal,
while 2533/133/PC800 (143s) outperforms the 2533/133/PC1066 (146s)
(if I got his notations correctly. There is some discrepancy
in the section that lists the memory used).

In any case, the REVERSED gain in performance should
trigger some questions. The answer could be as simple
as BIOS misconfiguration, but I think it is a
manifestation of a general scalability problem with Rambus.
I think the latency of PC1066 remains largely the same,
and this causes those weird discrepancies in
benchmarks scalability. Looks more and more like a dead
end, pawing the road to DDR+.

- Ali