Is what i'm experiencing below the so called 360-370fsb limit on async dividers only but not sync 1:1?

my P5W DH with 0801 bios with 2x1GB Gskill PC6400PHU2 HZ Micron D9GMH (0629) doesn't seem to like 4:5 upclock divider past 378fsb (gives 472mhz mem) for now Nor does it like 2:3 beyond 360fsb (gives 541mhz mem). This is with manually set timings of 4-4-4-12 regardless of vdimm used. Haven't tried setting SPD for memory to boot yet.

P5W DH i have doesn't seem to like 4-4-3 timings where tRP = 3 either, can't pass memtest86+ v1.65 higher than 460-472mhz 4-4-3 (manually set in bios) regardless of vdimm used or divider used. Same memory on Badaxe board did 488mhz 4-4-3-5 at 2.2v!

But 1:1 seems best for E6600 due to max fsb limitations I wonder how far i can go just for testing single Super Pi v1.50 32M

Testing max single Super Pi v1.50 32M:


vdimm = 2.3v (seems to help stable things due to tighter timings at 1:1 clocks especially when you get closer to P5W DH's max FSB wall)

Bios Settings:

vFSB = 1.3v
vMCH = 1.65v
vICH = AUTO
Performance mode = Standard
Hyperpath3 = Disabled
DDRAM Throttling = Disabled

* All tests are straight boot from bios with manual timings set at 4-4-4-8 4 at 2.3v
* All tests are untweaked with default P5W DH set timings. Have yet to even tweak with memset or drop tRP to 3 yet.

@3807Mhz - 9x423fsb at 1.55v bios vcore = 1.508 bios
32M = 13min 41.797s

@3897Mhz - 9x433fsb at 1.6v bios vcore
32M = 13min 16.672s

@3924Mhz - 9x436fsb at 1.625v bios vcore
32M = 13min 09.953s

@3942Mhz - 9x438fsb at 1.6375v bios vcore
32M = 13min 09.578s

Hit max FSB limit of vMCH 1.65v, raised vMCH to 1.75v

@3960Mhz - 9x440fsb at 1.65v bios vcore
32M = 13min 04.969s

@3987Mhz - 9x443fsb at 1.6625v bios vcore = 1.64v windows idle and 1.61-1.63v load
32M = 13min 00.750s