Problems getting high mhz with high fsb

[Fiskekrok]

Hello
I've been trying to overclock my 3500+ winchester but cant reach any good frequency while running high fsb.
Im using a 3500+ (CBBFD 0437WPGW stepping). Msi neo 2 mobo with latest bios i guess, and a pair of gskill memories with tccd.
Yesterday i tested the memories how high they were able to run. I ran some superpi and reached 300 fsb without any errors, with multiplier set to 7.5 = 2250 mhz. Then i increased the multiplier to 8x = 2400. Also ran rock stabil. So i thought what a h*ck lets continue. I set the multiplier to 8.5*300 = 2550 which resulted with bluescreen. I know from before that the cpu is stabil up to 2650 mhz (runing 10.5*250)

Have tried many combinations to run atleast 2600 mhz
11*236 = Stabile
10.5*250 = Stabile
10*260 = Not Stabile
9.5*273 = Not Stabile
And then to the question. What the h*ck is wrong? Why can't i for example run 260*10? My guess is that the memories are the failing link. But on the other hand, they should be able to run 275fsb with 2.5 3 3 7 timings without any problems, for now im using 3 4 4 8 timings 1:1 dividers.
All theories are welcome.

//Fiskaren

[Hvidgaard]

running 7,5x300 1:1 the real ram speed is "only" 280MHz

But my bet is that your memcontroller is not op to both high mem and cpu

[Fiskekrok]

running 7,5x300 1:1 the real ram speed is "only" 280MHz

Can you expalin that further?

So you think that the mobo is crapping out on me?

[Hvidgaard]

FSB	Mem	DDR	Ratio

200	100	(200)	2:1
200	133,33	(266)	3:2
(200	150	(300)	4:3)
(200	160	(320)	5:4)
200	166,67	(333)	6:5
200	200	(400)	1:1

Mem=FSB*Multiplier/roundup(Multi*ratio)

Multipliers lower than 5 is not supported, and will be treated as 5 when calculating memfrequence (Multi equals 5 if multiplier is 3-4,5).

Meaning if you run 7,5x300 1:1 you mem=300x7,5/roundup(7,5*1:1)=280Mhz

The memorycontroller is ondie on an A64 so i do not think that its your mobo, but your CPU that cannot handle both high mem and core. This is indeed a well known problem amongst Winchesters (including my own )

Have you tried to raise the Vcore a bit?