Is CL=10 memory OK for i5 2500K ?

I have Crucial Ballistix BL51264BA160A wich is CL 10, 1.5V DDR3 PC3-12800, timing 10-10-10-28.

Is that appropriate for my build (see .sig)?

No OC'ing (yet).

I have intermittent performance problems that seem to be triggered by very heavy VM usage (OS file buffers) and I'm clutching at straws as I try to figure out what's going on.

The latency doesn't affect system stability, at least not in the way you seem to think. Higher latency does in general terms mean a more stable system as you're not pushing the memory timings which can sometimes cause system instabilities, especially when pushed beyond what the modules can handle.

Strange modules though, as even for 1600MHz DDR3 memory, those are some really slow latencies where 9-9-9-X tends to be much more common even at those speeds. You normally tend to have to hit speeds of 1833MHz or more to get that high latency RAM.

For some comparisons of latency on Sandy Bridge and how it impacts performance, have a look here http://www.bit-tech.net/hardware/memory ... y-bridge/3 although CL10 isn't included and it's a slightly old test now, but mostly relevant.

Are you running the latest BIOS and the correct DSDT file to go with it, as that can sometimes solve stability issues.

Thank you very much for the information, EST.

I picked up the DIMMs at Microcenter. They seemed the best fit but I admit I wasn't paying attention to CL at the time.

I do not have the latest BIOS, F10. I am running F9 BIOS and the DSDT for that BIOS because 1) there is no DSDT for F10 and 2) the F10 upgrade over F9 is just for 22nm.

I am trying to find a simple repeatable procedure to demonstrate the problem. It is not easy. I can repeatably demonstrate it with a big MySQL batch job that takes a few hours and churns through ~50GB data. It runs fine for a while and then at a certain point (I don't understand the inflection) the entire system bogs down. e.g. Chrome or PhpStorm (IDE) become too sluggish to use and saturate 2 or 3 cores (doing what? I wish I knew. top(1) shows then in the running state), iTunes can't keep the audio stream up. It's a serious problem.

Yeah well, sometimes the BIOS upgrades do more than what is actually being listed as fixes, but that's besides the point.

Anyhow, I have no idea as to how to solve your issue, but a 50GB MySQL file is massive. I presume you're running in 64-bit mode?

thelostswede said:

Anyhow, I have no idea as to how to solve your issue, but a 50GB MySQL file is massive. I presume you're running in 64-bit mode?

Click to expand...

Yes.

I have been able to trigger the same problem with a simple script that reads files from directories recursively and writes to a 1GB circular buffer on the startup SSD. But this requires doing other things too, like browsing in Chrome, to trigger the problem.

As a benchmark and clue, PhpStorm takes about 30s CPU time to startup and load my current project. Once that read/write script has been running for a hundred GB or so, it tales about 5min CPU for the same task.

What's so curious is that PhpStorm is actually running on 2 to 3 cores for two or three minutes. It's not blocked or stuck. What CPU operations might it be executing during that time? Why does it take 10 times as many operations than after a fresh boot. (It similar with other big programs like Chrome, FF...)

So very odd...

If you're concerned about the memory and want to test it for problems, try this http://www.memtest.org/

Sorry, but I don't have any sensible advice to give beyond that.