I was overloaded at work that day. Let me correct another of my confusing hurried statements.
PC1066 with the new PCB form factor that fits the RIMM 4200, is the 32bit module for the next round of RDRAM memory architecture. (See page 4 of the <A HREF="http://www.rambus.com/rdf/presentations/RIMM3264_06.12.pdf" target="_new"><i>Rambus® 32 and 64 bit RIMM™ Module - Technology Summary</i></A> Note: That paper is from June 2001 and some things have changed, but you get the idea.) For the current PC1066 under RIMM 1600 and RIMM 2100, all are 16-bit. (Well except any engineering samples with the RIMM 1600 and RIMM 2100 form factor.) Here is another good paper on the RIMM 4200 showing the up to date layout of the RIMM 4200 module, use of both channels, clock speeds, etc. (Plus it is only 3 pages long...good for those who can only do a quick read.) It is the <A HREF="http://www.rambus.com/downloads/rimm_4200_white_paper.pdf" target="_new"><i>Rambus RDRAM® RIMM™ 4200 white paper - By Mike Feibus, Feibus SC -May 2002</i></A>.
As for PC1066 modules themselves...
"<font color=green>The 512/576 Mb RDRAM devices are extremely highspeed CMOS DRAMs organized as 32M words by 16 or 18 bits. The use of Rambus Signaling Level (RSL) technology permits 600 MHz to 1066 MHz transfer rates while using conventional system and board design technologies. 1066 MHz RDRAM devices are capable of sustained data transfers at 0.9375 ns per two bytes (7.5 ns per sixteen bytes).</font color=green>" - Taken from page 1 of the <i>Rambus 1066 MHz RDRAM 512/576Mb (8Mx16/18x4i) Advance Information Fact Sheet</i>. Look at page 16 and 17 of the <A HREF="http://www.rambus.com/rdf/presentations/1_05_RambusRoadmap_Fox.pdf" target="_new"><i>RDRAM RDRAM® Device and Device and RIMM RIMM™ Module Roadmap Module Roadmap - Frank Fox Frank Fox - VP, RDRAM Standards Division VP, RDRAM Standards Division Rambus Inc. Rambus Inc. - October 22, 2001 October 22, 2001</i></A> for a good explination for the 16 bit, 32 bit, and 64 bit module designs for the existing form factor using the RIMM 1600 and the RIMM 2100. But as you have seen from the Tom's, <A HREF="http://www.tomshardware.com/mainboard/02q2/020624/i850e-02.html" target="_new">Warp Speed with Rambus: Six Boards for PC1066</A> article you can see the RIMM 4200 form factor. It looks like they are using what they had designed for the form factor for the 64 bit. (See all of the Rambus papers above.) It looks like they needed to eliminate one of the keys for the extra pins. {That is just my speculation...}
Again, I apologize for the confusion... If the are any more mistakes please point them out so I can correct and/or clearify them.
Back to you...
<b>"Sometimes you can't hear me because I'm talking in parenthesis" - Steven Wright</b> :lol: