Question Do I need to run 2048K+ in Prime95 to stress test my XMP profile?


Feb 12, 2016
I've built a PC for a friend, and I'm currently running some tests to make sure everything work as it should.

If I've understood things right, normally when you overclock the RAM you want to run Memtest86, and then Prime95 in custom mode with a range of 512K-4096K, where 512K-1024K stresses the IMC and I/O-lanes, and 2048K+ stresses the actual DIMMs.
However now I only want to see if the XMP/DOCP is stable and works well in the system - do I then really need to stress test the DIMMs themselves with 2048K+ FFTs? Would be enough to just stress test the 512K-1024K range?
They are after all binned, and should work running at the marketed specs assuming the rest of the system works with the profile too.

Truth be told, he's picking the system up tonight so I'm a little short on time and can't run Prime95 for 8+ hours without telling him to come by tomorrow instead.
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Prime95/ blended (default) will stress RAM more than enough at default settings....

Even 10-15 minutes is likely more than enough, IMO.....

(If worried about intermittent RAM, you can run an overnight Memtest86 run...)


Dec 26, 2012
Prime95 isn't ideal for memory testing. Although it has some access patterns that are unusual for most memory testing utilities, it takes a very long time to detect errors. Memtest86 is originally designed to test whether memory is defective. As a result, it also works for OCs, but it only tests very specific scenarios that highlight bad memory and leaves a whole host of more 'natural' access patterns untested. This is why people use Prime95 and memtest86 as a complement to each other.

I have made a pretty great discovery when OC'ing my RAM: TM5 0.12 with the 1usmus preset found on the bottom of this page. Be aware that you have to download the correct configuration separately. I found that this test was able to generate huge error counts in around half an hour, where memtest86 ran for hours without any issue. I don't have enough data to actually say this detects everything, but it does find a lot and does so very quickly. In my experience so far, this test alone has been enough to conclude that a system is stable. I can in no way guarantee that this is the case for you, but considering it's only an XMP profile, I'd say it's very likely to be enough.