Remember when I was getting all those strange crashes when trying to encode MOV files? And the crashes were both on the PC and the Mac?

If you followed that thread, you'll recall that the Mac side of the problem was having installed the Divx codec, and the PC side of the problem was a bad RAM stick whose symptoms didn't show up until after a few passes into Memtest.

I got the replacement RAM stick for the PC. The bad one was part of a matched pair of Corsair PC3700. The replacement they sent me was PC4000.

I'm putting them in the paired slots, and all seems OK at first, memtest passes several passes, but I can't run any 3D video game for more than 10 minutes without a crash, even after rolling back to known-good video drivers.

Is it possible that having the mismatched pair is the issue? What happens when you have paired RAM sticks that are two different speed ratings like that?

Maybe the BIOS makes its memory timing decision based upon the new stick? You could try swapping the modules between sockets.

Just recently, I've been fixing numerous systems with a patch that addresses problems introduced by KB916089. The patch appears to be pretty safe and it performs a pre-installation check to determine whether it should be installed. I've 'fixed' about 8 crashing PCs in the past week with this magic bullet - definitely worth trying IMO.

Thanks Andrew. I will try both of your suggestions. That hotfix looks really interesting. It doesn't say what it's fixing at all, it'd be interesting to know more.

Neither swapping the modules nor installing that patch fixed the crashes.

What fixed them was altering a setting in the system BIOS, in the section that handles all of the DRAM timings. Buried in all of the options, just under the CAS latency, was a cryptic option called "performance acceleration mode". The help on the item simply said it would reduce latency between the CPU and memory. It had two options: [Enabled] and [Auto]. I'd always been able to set it to [Enabled] before, but now it's got to be set to [Auto] for the system to work crashfree.

Since the help text is unclear as to what it's accelerating, I'm not sure what performance levels I'm losing by changing it. So I'm not sure if this is a "fix" per se. For all I know, this could be what controls the ability of the memory to work in paired slots, and by setting it to Auto, I'm now losing the performance gain I originally had by using a matched memory pair.

*sigh*.

If you purchased two sticks of memory as one product, they should replace the whole product. Did you tell them that that was the case when you returned it?

I don't want to (completely) hijack the thread, but my brother's notebook is crashing at some access violation on a bluescreen very soon after booting into XP. He doesn't recall having installed any applications or doing anything to the system that would have cuased this. It's possible it happened after an automatic system update though.

Can this patch (mentioned above) be installed while running in Safe Mode? I'm not sure if he can get into Safe Mode, but I'm just worried the system won't otherwise stay up long enough to get it installed. After it crashes, Windows will usually want to check the disks on a reboot, which makes the whole process of restarting painfully slow.

Aha. According to this, the Performance Acceleration Mode setting is

Quote:
a technology for 875 mobos that increases overall performance by 3-5%. the 865 implements a technology known as gat, or gaming accelaration tech. It's for DDR400 (PC3200) or greater, in conjunction with a 800 mhz FSB CPU. It allows the RAM and CPU to run synchronously at 1:1 with the RAM on a 2x multiplier and CPU on 4x multiplier.

Other searches tell me that I should be able to turn this feature to "On". But it doesn't work with that new stick in the mix. For now, I'm just going to not worry about the tiny performance gain, and just leave it off.