45nm chips and FSB OCing are doing my head in

[dinos22]

hey fellas

i always approach overclocking through trial and error and most of the bench sessions i spend messing for hours on end testing small bios changes for specific component OCing...like RAM frequency/latency/MHz, motherboard max FSB, mobo most efficient FSB (tight MCH Performance Level) etc etc

well tonight was one of those let's see what FSB i can boot from bios kind of night lol

what's doing my head in is as of late i've had a fair few motherboards that can hit high FSB but for stable FSB i have to drop MHz by a coutry mile

from tonight
Max stable 3D/2D 550MHz FSB
Max 1M SuperPi ~ 575MHz FSB
Max boot FSB ~ 630MHz FSB

this CPU usually gives me 520MHz stable FSB on X38/X48 boards and 530-535MHz 1M SuperPi sort of FSB

on P5B DLX C2 revision i could hit 628MHz FSB screen and 620MHz 1M SuperPi stable

what's going on with 45nm chips and FSB OCing......what am i missing here....
it seems i'm not alone as others are struggling to do some decent FSB OCing (600+ on air and it's clearly possible considering what we've seen on 965 C2 chipset)

Test Setup

• GIGABYTE EP35-DS3P PCB REV 2.1 (BIOS F2)
• E8500
• TTBigTyphoon Air Cooler
• 1GB stick of Corsair PC8500 DDR2 RAM (Micron IC)
• Gigabyte 9800GX2 (i am using it on purpose to see where i could get 3D with this card)
• Seasonic X900 PSU
• SATA HDD

572MHz FSB bios boot
http://valid.x86-secret.com/show_oc.php?id=362739






i'll stick it under single stage when i get a chance to see what cold does........
i've noticed thought that cold didn't help with FSB much as it used to in 65nm chips....

i've noticed some weird behaviour with FSB OCing and volt changes with vFSB, vPCIe, vMCH

i found that for 625MHz FSB post i could use vFSB=+0.25, vPCIe=+0.05, vMCH=+0.225

raising MCH or vFSB or vPCIe would reduce FSB OC

i'll also try different tREF values as i did have some luck in the past with X38 boards

any suggestions or dicsussion on this 45nm FSB OCing topic welcome....i'd like to hear other ppls opinions

[STEvil]

could be your heatsink on the northbridge.

I've got a giant chunk of copper heatsink on mine and it runs pretty warm.. I dont see how those tiny stock things can be helping.

[dinos22]

i donno man it was very cool to touch and i wasn't really pushing any serious volts but i will pull it apart to see if it was making good contact
maybe i can slap a Swiftech NB cooper heatsink and see how it does with that

[Speederlander]

What is max stable 24/7 solid FSB thereabouts? How far off your benching level is that? Is it typically less than 550 or right around that point?

[metro.cl]

Ohhh Dinos i completely understand you but i dont have quite the same issue as you, i can get my FSB over 550 and i've tryed a lot of things.

Then if i leave everything at auto on Asus BIOS i get almost the same FSB, so i'm kinda going crazy.

I could only tell you that more volts to the NB really helped me on FSB.

[dinos22]

What is max stable 24/7 solid FSB thereabouts? How far off your benching level is that? Is it typically less than 550 or right around that point?

hi mate

i don't really check full prime stability on my benching machines as it makes no difference for me at all....

i am specifically looking for ultra high FSB mobos which can reliably run 16x PCI Express slot

Ohhh Dinos i completely understand you but i dont have quite the same issue as you, i can get my FSB over 550 and i've tryed a lot of things.

Then if i leave everything at auto on Asus BIOS i get almost the same FSB, so i'm kinda going crazy.

I could only tell you that more volts to the NB really helped me on FSB.

auto everything on this board and i cannot boot at 550MHz let alone 630 hehe

but the funny thing is if i set all volts just one notch up from minimal settings >> so +0.05 in bios i can bench 550 almost.......another small notch in NB and i'm stable

once i put some more volts in any of the volts i lose stability but i don't think this is heat related but rather a coc.ktail of volts required to hit ultra high speeds

[Loser777]

Tried a Quad with this board?
Pretty cheap for such an OC.

[dinos22]

these are probably some of the best boards around
cheap and OC really well

even with current OC it's waaaaaaaaaaaay better than any other board i have but the fact i can do a lot more if i can somehow figure it ..........well it would be even sweeter

i have a feeling that it's the mix of CPU Skew and GTL Ref that i am essentially missing here and it's not in the bios to change either.....

maybe time to see if any newer bios files have these options too