Crosshair Overclocking problems

I posted this in the AMD motherboards section but recieved no response other than try posting in the AMD CPU section as it sees more traffic:

I have had some confusion overclocking the ASUS Crosshair with the AMD Athlon 64 X2 6400+ CPU. I am currently at 228Mhz on the FSB (3648 Mhz CPU frequency and 912 Mhz RAM frequency). I am Prime 95, Orthos, 3Dmark 01, 03, 05, and 06 stable. However, it won't pass Super Pi (not exact in round error) for more than a few minutes. It also crashes or locks up when my wife plays Nancy Drew Mysteries. I would like to find the cause of this instability.

To be at this partially stable state, I have the Vcore running at 1.472V. If I raise it all the way up to 1.600V, it is still similarly partially unstable. So I'm thinking that it is not the Vcore being too low. Temperature is not an issue. I am running an Asetek 3X120mm water cooling system and my CPU temps never go above 38 C.

I understand that with this overclock, my HTT is running at 1140 Mhz. I have seen reviews where this is pushed to above 1250 Mhz. Just in case my motherboard will not run with the HTT at 1140 Mhz, I changed the CPU<->NB HT speed from 5X to 4X which gave me a HTT speed of 912 Mhz. Still the same problem. So, it's not a HTT problem. I changed it back from 4X to 5X. I then ran Memtest 86+ ver 1.70. It passed through three runs with no errors. Some say that this should be run for at least 24 hours to prove stable, but I get the Super Pi error within three minutes. So, I'm thinking that I don't have a RAM problem.

What can the cause of this instability be??? I have seen the multitude of BIOS settings and not all of them are familiar. Could it be that I need to change some of the more obscure settings??? If it is not corrected by alot more Vcore, and also not corrected by lowering the HTT speed, and the RAM is not at fault, then what can it be????

run memtest86+ please.

If it passes memtest, try bumpbing NB voltage one bump to see if that helps.

Thanks for the advice. I did run Memtest 86+ ver 1.70 with no errors for three runs. I will try the NB Volts tweak.

This is the first motherboard/CPU that I have reached the instability point without it being a thermal concern or lack of Vcore. I have raised Vcore from 1.472V (partially stable) to 1.600V (still partially stable). The CPU never goes above 38C so its not a thermal concern either.

I figured that I would have to adjust one of the following to gain extra stability when overclocking (I have so far left them all at AUTO settings):
HT Link Voltage
NB Core Voltage
SB Core Voltage
SB PPL Voltage

WildWillie said:

This is the first motherboard/CPU that I have reached the instability point without it being a thermal concern or lack of Vcore. I have raised Vcore from 1.472V (partially stable) to 1.600V (still partially stable). The CPU never goes above 38C so its not a thermal concern either.

I figured that I would have to adjust one of the following to gain extra stability when overclocking (I have so far left them all at AUTO settings):
HT Link Voltage
NB Core Voltage
SB Core Voltage
SB PPL Voltage

Click to expand...

Willie,
You may just have tapped the proc...these things are already close to their limit for this architecture. Also, how long did you Prime95 it? Usually I can pass SuperPI, but fail Prime95? I can boot to Windows at 3550, but get random bsod's/lockups. I figure my sweet spot is somewhere around 3450/

1hawaii50 - Thanks for the post. Our systems are similar. During stability testing, I would run Super Pi and Prime 95 simultaneously. Super Pi would fail within 3 minutes, Prime 95 would run for at least five minutes, but I never saw a fault (didn't let it run long enough). When I saw that it was unstable, I would reboot and try something else.

So we are not Vcore limited, thermally limited, RAM limited, or HTT limited. Just CPU limited and there is nothing we can do about it? I just upgraded from an Athlon 4800+ (2400Mhz) that I had overclocked to 2800 Mhz. It was pretty smooth, just add a little more Vcore for stability and raise it some more. It would not raise above 1.600V no matter how high the Vcore setting was, but this was enough for 2800. Someone mentioned raising NB Voltage. What do you think about this??