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synchronicity in prescott 2.8E FSB800 vs FSB533

Posted: Fri Sep 24, 2004 6:02 am
by joaoh
hi all,

I read that to o/c this p4 is best to run FSB/RAM sync 1:1. I was planning to buy this p4 with
FSB 800 and ram DDR 400 wich made for that ratio. But there isn´t that processor so the dealer
told that he could manage the 533 mhz (133) with the ddr400. There seems to be an interesenting
gap to fill since to get the 1:1 you can puxh that FSB 67mhz while not messing with RAM.

I've seen most guys taking round 50hz o/c a Prescott 2.800mhz FSB 800 to 3.5 or 3.6, since the multiplier stays
always 14 (2800/14= 200 = FSB 800) and 250x14 makes 3500 mhz.

Question 1) Do they push RAM to 250mhz too in order to stay sync? The answer is yes? And of course vdimm..etc

Question 2) If I have the FSB 533, the gap between RAM and FSB to run sync is 67mhz, which i guess
can never be fulfilled because the multiplier is 21 (2800/133) and 67*21=1407 wich added to 2800
makes for a impressive 4207mhz??? This would be a heck of a machine... If this is not possible is
it worth to try the async mode in this p4? makes me wonder how??

what do you think of this guys?

Posted: Fri Sep 24, 2004 9:23 am
by Apoptosis
So you're telling me that no local dealer can get an 800MHz FSB processor in? If so that is a bummer. Running a 533FSB w/ PC-2700 memory (DDR333 or 166x2) is ideal for that FSB. I'd still go with PC-3200 memory for more headroom for overclocking though.

Answer 1) On my prescott system I run it in 1:1 @ 250. I run 2.7Vdimm
Answer 2) I'm not sure exactly what you mean on 2, but you want to overclock it 67Mhz on the core and run 1:1? (that would be 200x21= 4.2GHz... not going to happen on a 533FSB processor)

Posted: Fri Sep 24, 2004 9:54 am
by joaoh
tanx apop, u hit the point!

I´ll squezze the dealer to get that 800FSB or else i´ll buy it myself from another vendor