775lga fsb hole?

Nov 26, 2005
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I'm curious about my old Q9550, UD3R, & DDR2 1000 setup. I know the ram is stable @ 1:1, my Q9550 will do 500fsbx8 @ 1.375v bios 1.34v OS, and my board has been stable with my old Q9650 all they way from 333 through 500fsb. Deductive logic says the Q9550 is the problem but that's not always the case. I couldn't get it stable anywhere between low 400's to 475 I'm thinking of resurrecting it for some OCing & h20 cooling fun but I don't want to get sucked into buying parts for it while my rig3 in sig isn't built. If I do, I want to be sure what the problem is - I know, sometimes it's hard to tell, so that's why I am poking around here to pick the brains of the Almighty Anandtech forum members :)

I'm thinking its the board - any other thoughts or experiences you'd like to share?

Thanks,

529th
 

n7

Elite Member
Jan 4, 2004
21,281
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I don't have any precise answers, but there haven't been any actual "FSB holes" on Intel boards since the days of P965 when straps made life funky @ certain speeds.

"FSB holes" do exist on nForce chipsets though.

In your case i'd go with different CPU = different voltages/settings needed.

Just because your board requires one set of voltages/setting for one CPU doesn't mean it'll do the same for the next.

My high FSB setting for my Q9550 were not identical to my Q9650.
I thought that i could re-use the same kinda settings, but it didn't take long to realize i needed to redo VTT/NB + GTLs (which is likely your case also).
 

Gillbot

Lifer
Jan 11, 2001
28,830
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I don't have any precise answers, but there haven't been any actual "FSB holes" on Intel boards since the days of P965 when straps made life funky @ certain speeds.

"FSB holes" do exist on nForce chipsets though.

In your case i'd go with different CPU = different voltages/settings needed.

Just because your board requires one set of voltages/setting for one CPU doesn't mean it'll do the same for the next.

My high FSB setting for my Q9550 were not identical to my Q9650.
I thought that i could re-use the same kinda settings, but it didn't take long to realize i needed to redo VTT/NB + GTLs (which is likely your case also).

I'll respectfully disagree there. My MSI board HATED anything near 450fsb with any quad and took insane voltages to keep a C2D stable around 450fsb. I think they still do exist, but they aren't a true "hole" as it may vary with the CPU.
 

n7

Elite Member
Jan 4, 2004
21,281
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I'll respectfully disagree there. My MSI board HATED anything near 450fsb with any quad and took insane voltages to keep a C2D stable around 450fsb. I think they still do exist, but they aren't a true "hole" as it may vary with the CPU.

I wouldn't consider that a "hole", that's a reaching-your-boards-limit scenario.

"FSB hole" would be if you couldn't do 399-401 FSB, but could easily run 402 or higher.

And i don't even like that terminology, since for P965, once you understood that reason was due to a strap change (therefore lowering the NB clockspeed), it made sense (albeit annoying).
 

WildW

Senior member
Oct 3, 2008
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evilpicard.com
My P35 + E5400 has FSB issues. . . it will happily sit at FSB values around 200/266/333 plus or minus 4 or 5 MHz, and values between (e.g. 220, 250, 300, etc) will not even POST. I suspect the motherboard rather than the CPU, but I could be wrong I suppose.
 

Gillbot

Lifer
Jan 11, 2001
28,830
17
81
I wouldn't consider that a "hole", that's a reaching-your-boards-limit scenario.

"FSB hole" would be if you couldn't do 399-401 FSB, but could easily run 402 or higher.

And i don't even like that terminology, since for P965, once you understood that reason was due to a strap change (therefore lowering the NB clockspeed), it made sense (albeit annoying).

My msi did 650+ fsb stable so i was no where near it's "limit", it was a hole.
 

tweakboy

Diamond Member
Jan 3, 2010
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www.hammiestudios.com
Every CPU is slightly different. That is such a nice low voltage you got there. What is your NB voltage. You would have to do 1.7v on fsb to be stable at the highs you want. gl
 

n7

Elite Member
Jan 4, 2004
21,281
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My msi did 650+ fsb stable so i was no where near it's "limit", it was a hole.

Ah, interesting.

Outta curiosity, what different RAM ratios did you try around that "hole" area?
 

Gillbot

Lifer
Jan 11, 2001
28,830
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Ah, interesting.

Outta curiosity, what different RAM ratios did you try around that "hole" area?

Unfortunately the lowest you can go on P35/P45 is 1:1, but running good D9 ram means you can hit 650+ without much worry. ;)

I also tried various straps to see and those made little difference overall.
 

n7

Elite Member
Jan 4, 2004
21,281
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Unfortunately the lowest you can go on P35/P45 is 1:1, but running good D9 ram means you can hit 650+ without much worry. ;)

I also tried various straps to see and those made little difference overall.

Ah, i mention it because it's generally considered easier to get higher FSBs (particularly w/ quads) when NOT using 1:1 (i.e., use 5:6), at least for my P5Q-D & the UD3R/Ps, anyway.