Many thanks for your valuable response. This weekend I will take the
systematic approach as suggested by yourself. One thing at a time :-)



Michael Brown wrote:
|| James Bond wrote:
||| I purchased this mainboard soon after it was released and fitted it
||| with Corsair XMS2-5400 DDR2 RAM, P4 540 3.2E GHz CPU (D0 stepping),
||| Abit RX600 XT-PCIE graphics card, and Creative Labs Sound Blaster
||| Audigy2 ZS Platinum Pro PCI card. I have 4 x 250GB SATA hard disks
||| in two RAID arrays (using the onboard RAID).
|||
||| I then added watercooling using Asetek blocks on the CPU, VGA, and
||| NB.
|||
||| The best semi-stable overclock I can manage is about 240/3840 MHz.
||| This is done with the following settings:
||| VCo 1.6125V, DDR2V: 1.90V, NBV: 1.70V
||| CPU temp at idle: 45C, CPU temp at load: 56C, Ambient temp: 25C
|||
||| On very hot days the CPU full load temp approaches 60C, whereafter
||| the machine normally crashes.
|| [...]
|||
||| I suspect that the overclocked PCIe bus might be at the root of this
||| problem.
||
|| If it was the PCIe bus, I suspect you'd be seeing it long before
|| 240MHz. Most PCI start to malfunction around 37-38MHz (corresponding
|| to a FSB of ~225MHz), but your system is (almost ) stable at
|| 40MHz. Perhaps PCIe devices are more tolerant to an overclocked bus,
|| I don't really know.
||
|| What you need to to is take the standard overclocking approach and
|| isolate each part by itself.
|| 1) Get rid of the SB card.
|| 2) If you have a PCI graphics card that you're familiar with (in
|| terms of what it will take), use that instead of the X600
|| 3) Remove everything except video card, RAM, and CPU.
|| 4) Find the limit of you RAM. Keep the FSB and memory speed in sync
|| (or even run the memory above the FSB if possible) and ramp up the
|| speed until memtest86 gives errors (or the system fails to boot ).
|| 5) Find the limit of your CPU. Ideally, use a bootable Linux CD
|| image along with Prime for stability testing (there's several out
|| there, but don't know the names off the top of my head).
|| Alternatively, use a hard disk you're familiar with, or one of your
|| SATA drives if you don't have anything valuable on there yet. Do not
|| use RAID. I usually let Prime run for about 5 minutes during the
|| "first stage", increasing the FSB if it can last 5 minutes. When it
|| starts to error, keep backing down until it can do a full 24 hour
|| run. You may also want to drop the RAM speed a notch to be
|| absolutely sure that there's no problem there.
||
|| If you do this, you've largely isolated the two main components (CPU
|| and RAM). Pick a speed that both should work fine at, and slowly add
|| components. Run a test that focusses on that particular component
|| (for example 3DMark to make sure your graphics card is happy). You
|| should then find where your stability problems are, or alternatively
|| end up with a system that is stable, and pretty much sitting at the
|| maximum speed possible.
||
|| If it's your CPU which is limiting you (which I suspect, given that
|| you mention that temperature has an effect on stability) then run
|| one of the throttle-monitoring programs. If your CPU is throttling
|| at high loads, then you're just going to have to back down the
|| voltage/frequency or cool it better.
||
|| Another thing to try is to take the side off your case (if it's in a
|| case) and blow air in using a desk fan. One "problem" with
|| watercooling is that it changes the airflow across the motherboard
|| from what has been designed. The airflow from the NB fan (for
|| example) might also be cooling a couple MOSFETs. With the fan
|| removed, these components heat up more under load and can cause
|| stability problems. Creating a lot of airflow across the board will
|| show if this is potentially an issue (though won't resolve it
|| entirely, as it will also cool down things like the CPU, etc).
||
|| Overclocking is a continual process. You don't just get your system
|| and immediately go to the highest possible speed. You find the
|| limits of each component, and continually explore different
|| configurations, different cooling methods. It can take months of
|| weekend fiddling until you get close to the maximum of your system.
|| I was still getting improvements out my main system a year after I
|| installed most of the bits, using pretty much the same cooling
|| components as I started with. Also, every system is different. You
|| need to find out the limits orf your particular system by isolating
|| components and testing them. Overclocking everything at once it not
|| the way to go, as you end up in the situation you are now, unsure of
|| where or what the problem is.
||
|| [...]
|| --
|| Michael Brown
|| www.emboss.co.nz : OOS/RSI software and more
|| Add michael@ to emboss.co.nz ---+--- My inbox is always open