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J&SB
Guest
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 Posted: Mon Apr 02, 2007 12:40 am Post subject: Strange stability issue with K8WE and 16GB RAM |
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My K8WE (2895) with dual Opteron 280's and 8GB RAM (in the form of four 2GB
DIMMs of Crucial PC-3200, 2 DIMMs per processor) has been running flawlessly
for nearly 18 months now under Windows XP-64. Just last week I fulfilled a
need to fill out the 4 vacant RAM slots with identical DIMMs to bring the
total to 16GB. Upon booting up after the installation, everything was
recognized and ran just fine.
Following the installation, I wanted to do a bit more testing to see if my
performance had drooped any, and so I ran the Sandra 2007 memory bandwidth
test. The test completed, showing a 10300MB/s performance, but triggered a
"soft" Machine Check Exception along the way (e.g. indicating that a
correctable error was encountered along the way.) I then ran 4 simultaneous
instances of Prime95, and continued to get several more of these Machine
Check Exceptions throughout 4 hours of running, but no errors indicated by
Prime95. Then, out of the blue, I encountered a fatal Machine Check
Exception that triggered an automatic reboot. Following this, I ran
Memtest-86 for 24 straight hours without any error whatsoever, so it's
difficult to believe there is a problem with the RAM. Nevertheless, the
"soft" Machine Check Exceptions continue to occur whenever I run the Sandra
2007 memory bandwidth benchmark or Prime95.
Now the interesting thing is that I subsequently discovered the following
remedy (I'll skip over a lot of trial and error to get at the repeatable
consequence of my testing): Using CrystalCPUID, I change the CPU multiplier
from 12x to 11.5x and the CPU voltage from 1.35v to 1.40v, and then
immediately change both of these values back to the default 12x and 1.35v
respectively. After performing this trivial exercise, which in principle
changes nothing, I observe absolutely rock-solid stability with any Sandra
2007 benchmark and hours of running of 4 Prime95 instances. What gives?
Obviously, this procedure of toggling back-and-forth the multiplier and
voltage has some positive effect, but I don't understand it. Has anybody
seen behavior like this? |
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J. Hinkey
Guest
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| Posted: Wed Apr 04, 2007 12:35 am Post subject: Re: Strange stability issue with K8WE and 16GB RAM |
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J&SB wrote:
| Quote: | My K8WE (2895) with dual Opteron 280's and 8GB RAM (in the form of four 2GB
DIMMs of Crucial PC-3200, 2 DIMMs per processor) has been running flawlessly
for nearly 18 months now under Windows XP-64. Just last week I fulfilled a
need to fill out the 4 vacant RAM slots with identical DIMMs to bring the
total to 16GB. Upon booting up after the installation, everything was
recognized and ran just fine.
Following the installation, I wanted to do a bit more testing to see if my
performance had drooped any, and so I ran the Sandra 2007 memory bandwidth
test. The test completed, showing a 10300MB/s performance, but triggered a
"soft" Machine Check Exception along the way (e.g. indicating that a
correctable error was encountered along the way.) I then ran 4 simultaneous
instances of Prime95, and continued to get several more of these Machine
Check Exceptions throughout 4 hours of running, but no errors indicated by
Prime95. Then, out of the blue, I encountered a fatal Machine Check
Exception that triggered an automatic reboot. Following this, I ran
Memtest-86 for 24 straight hours without any error whatsoever, so it's
difficult to believe there is a problem with the RAM. Nevertheless, the
"soft" Machine Check Exceptions continue to occur whenever I run the Sandra
2007 memory bandwidth benchmark or Prime95.
Now the interesting thing is that I subsequently discovered the following
remedy (I'll skip over a lot of trial and error to get at the repeatable
consequence of my testing): Using CrystalCPUID, I change the CPU multiplier
from 12x to 11.5x and the CPU voltage from 1.35v to 1.40v, and then
immediately change both of these values back to the default 12x and 1.35v
respectively. After performing this trivial exercise, which in principle
changes nothing, I observe absolutely rock-solid stability with any Sandra
2007 benchmark and hours of running of 4 Prime95 instances. What gives?
Obviously, this procedure of toggling back-and-forth the multiplier and
voltage has some positive effect, but I don't understand it. Has anybody
seen behavior like this?
I have not seen this exact behavior (toggling CPU voltages or multipliers to fix things), but I have seen/experienced instances where the BIOS |
says a setting is set to a certain state or value when the machine was acting like it was set to something else. Toggling it or re-setting it
has changed things (usually for the better). This is kind of scary since you don't know what settings are actually active on your computer!
It may have been that your BIOS was corrupt and the toggling set things right. Re-flash the BIOS? Me, I'd just leave it alone for now.
- John |
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