Сколько проходов достаточно с Memtest?

Testing can not prove the absence of bugs, only their presence

Memtest is great for finding errors in RAM. The rate at which is find errors is by necessity inversely proportional to how broken the RAM is. The more broken it is the faster it finds errors.

90% of the time, if the RAM has a problem, memtest will find it within 10 seconds, 99% of the time, one pass will be enough to find the issue. The longer it takes to find the issue, the more subtle it is and the less likely it is the cause a problem with your PC (but you should still get new ram if you get even one error)

As the your computer is crashing quite frequently and you have run a few passes, It's probably not your RAM. As a next step, you should test you hard drive and then CPU with a tool such as Ultimate Boot CD or Hiren's. (Most modern BIOS's also have a built in HDD testing feature)

I've run memtest and seen 6 passes with no errors, with 4+ errors per pass after that. I normally just run 3-4 passes, but it's certainly possible to miss errors by doing just a couple of passes. I'd imagine that some errors only pop up as the memory modules heat up, thus causing problems with memory running at a high voltage.

At work we usually left the machines running over night, but in all fairness, every time I've been able to show a memory problem with memtest it has been within seconds of starting it.

I've never seen a machine do 1 full pass to fail on one the following. (Not that it is necessarily impossible, just to show that it is rare.)

I used to work in a computer shop where we started memtest on new machines on a more or less daily basis.

Without enough info to really say so I'd still guess your problem is likelier an over heating or bad driver one.

Since you've tried more than one OS the driver part seems unlikely. Unless you've for example only tried different windows versions that use the same driver.

http://hcidesign.com/memtest/manual.html

100% покрытие означает один полный проход тестирования вашей памяти. В общем, лучше запустить несколько проходов. Вот три типичных периода тестирования, которые вы можете использовать:

1. Тестирование до 100% покрытия (быстрый тест, чтобы убедиться, что ваша RAM работает нормально)
2. Тест на 1 час (это поймает все, кроме случайных ошибок)
3. Тестирование в течение ночи (рекомендуется; в любом случае, ваш компьютер больше ничего не делает ночью, почему бы не быть абсолютно уверенным, что у вас хорошая ОЗУ?)

I have seen RAM pass the first 6 passes of memtest and then fail subsequent passes, and when running a Linux OS with that RAM would see locking up after a 6-8 hours. Other RAM on the same motherboard ran fine, so apparently the failing RAM was temperature sensitive.

When I suspect a RAM problem (e.g. Dell computers with diagnostic lights) I run memtest on one RAM module at a time in the first slot for 8-16hrs. If it passes that confirms both that slot and RAM module are good and I can (more) confidently use that slot to test other RAM modules.

My experience with memtest86+ differs a bit from most people here. memtest86 has helped me a lot along the years but unfortunately it sometimes fails to detect errors.

Although memtest works the majority of the time, it failed me a couple of times. The first time it failed to detect errors i had a PC with 1x 4GB DDR3 that was giving me BSODs related to the memory. I ran memtest for an entire day, we're talking about 15+ passes but no errors. I then tested it on a completely different computer, same thing, no errors. Operating system was completely unstable but no errors on memtest. I then used a different software named "PC-Check" from Eurosoft which is very similar to memtest but uses different algorithms. It is also bootable, does not need any operating system. It detected errors in less than 5 minutes. I then was able to send the module to Corsair RMA and get a replacement.

So, memtest is very good but not always enough. I currently use memtest and PC-check to check memory. If memtest fails to detect errors, PC check certainly will and vice versa. And trust me, it happens more often than one would think.

Given that, after one pass, it displays Pass complete, no errors, press Esc to exit, I always assumed that's sufficient.

I do one pass to see if there are any obvious errors.

If there is an error no more passes needed.

If the problem with the computer is strange i let it go overnight or over day for ~10 hours just to be sure.

I usually run memtest EVERY TIME I change CPU, memory or notice odd issues. Reason is - memtest does not just test memory. It will error out in three other important cases:

1) If there are issues due to overheating of either CPU or memory. Normally, memtest loads CPU for several of the tests to almost 100%.

2) if CPU cannot access memory correctly. Most of the tests read & write at all locations of the memory.

3) if there are problems with power. I.e. a weak power supply or bad capacitors cause too many spikes offsetting random bits.

If I see at least a single red error, I start looking for what should be removed / fixed before using the hardware.