A query about FSB & RAM speed

I've come to a conclusion that under overclock the system runs most stable when the RAM is running at the next available frequency(faster) than 1:1.

To test stability i used one custom test. The test consists of looping any mpeg-1 clip in WMP(any version) or any other player that uses windows default mpeg encoder (ex. ZoomPlayer) while running OCCT in the background. I tried simply OCCT(8+ hrs) & Prime95(12+ hrs) too, but no error occured. But with my test the system locks up. I tried it on both XP sp2 & Vista all drivers & BIOS updated.

Few examples-

FSB - Memory clock mode [unlinked]
FSB(QDR) 1600Mhz
Mem(DDR) 800Mhz (here its 1:1 ratio but not stable a/c to my test)
Mem(DDR) 854Mhz (next available frequency after 800Mhz resulting stable)

FSB(QDR) 1715Mhz
Mem(DDR) 857.5Mhz (here its 1:1 ratio but not stable a/c to my test)
Mem(DDR) 915Mhz (next available frequency after 857.5Mhz resulting stable)

FSB(QDR) 1800Mhz
Mem(DDR) 900Mhz (here its 1:1 ratio but not stable a/c to my test)
Mem(DDR) 960Mhz (next available frequency after 900Mhz resulting stable)

Now the question is - is this only limited to my case ?

More system details -
MoBo - XFX 680i LT
Proccy - e6550
RAM - Transcend JetRAM DDR2 800
Core Voltage - 1.31V
FSB Voltage - 1.4V
SPP Voltage - 1.4V
RAM Voltage - tried upto 2.3V
Power Supply - Cooler Master iGreenPower 500W

this is interesting, have you updated the bios on the board? what bios are/did you run for those tests?

I tried P01, P06 & P07. Tried with all the Intel thermal & power saving settings enabled/disabled in the BIOS. In all the cases same result.

Did I mention that the same thing used to happen in my XFX 650i Ultra too(rest of the components were same) ?

And thanks for the reply as I thought people won't find it interesting.

try stock fsb on 1:1.. there are some unstable spots in the memory controllers on the nv.. as 1:1 for the nv board i used stuck the ram at the same speed as the cpus QDR fsb. try unlinked mode at 400fsb and then set the memory to the same speed. that is a true 1:1 ratio...

At stock FSB when I run the RAM at 1:1 everything works perfactly. But with a FSB(QDR) of 1600Mhz and Memory(DDR) set to 800 Mhz (unlinked mode) my test fails. Today I tried replacing my RAM with Corsair TWIN2X2048-6400C5DHX. Same results again.

then with it unlinked it might be one of those holes but thats weird...

Can it be such a big hole ? And moreover the same thing happened to my XFX 650i Ultra too. Or may it be possible that I'm one unlucky guy to have a badly overclockable processor ? Because this is the only component I haven't tried changing in my setup.