A la hora de hacer overclock es tan importante la técnica como el saber comprobar la estabilidad del componente. Es cierto que existen múltiples softwares que comprueban dicha estabilidad, pero en ciertas ocasiones necesitamos algo más específico. Por ejemplo, a la hora de probar las memorias RAM, ya que es un componente muy delicado y necesita de la mayor precisión. Por ello, hoy os enseñaremos a usar dos de los programas más extremos para memorias RAM: Runmemtest Pro + HCI Memtest.
Ambos programas son complementarios, donde la base es HCI MemTest, un conocido software (ya veterano) que exprimirá nuestra memoria RAM al límite. En cambio, Runmemtest Pro es un software complementario que nos facilitará el uso y monitorización del primero, todo de manera muy sencilla.
Sobre los datos en MB en color rojo, tal y como indica la fórmula, lo que veremos es el número de instancias que se abrirán de HCI Memtest por los MB que restan del número total de la RAM entre el número de hilos de la CPU. Es decir, si tenemos un procesador con 6 núcleos y 12 hilos, Runmemtest Pro 4 abrirá 6 instancias de HCI Memtest con igual tamaño de RAM asignado, para así cubrir el 100% de la memoria bajo estrés.
Como vemos, debido a nuestro Ryzen 5 3600X lo que tenemos son 6 aperturas de HCI Memtest con 1435 MB asignados cada una. Runmemtest Pro 4.1 coordina y monitoriza en tiempo real los errores registrados en cada asignación por núcleo, donde podremos ver la cobertura y el número de errores.
Por defecto, Runmemtest Pro trabaja con una cobertura del 100% y parará si encuentra más de 3 errores. Esto lo podemos modificar en la pestaña Advanced, donde deberemos incluir pasado el test del 100% un valor de 400%, el cual es el indicado por todos los overclockers del mundo como garantía de que la memoria es completamente estable, así como el IMC del procesador.
My computer hangs at random on multiple occasions and on different OSes today, requiring me to hit the reset button. I suspect it could be a memory problem and did a memtest with memtest86.
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)
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.
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.
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.
In most cases memtest will start spitting out errors within a minute if the RAM stick is bad. If you ask me, I'd say after 1 minute without errors you can be 50% sure that the RAM is good. After 5 minutes it's 70%. After one pass it's 90%. After 3 passes it's 99.9%, and so on.
Given this perspective, I have a different take on number of passes. When I buy a new machine (literally or new to me on ebay) I run it for 1-3 or 4 weeks depending on my patience. After that, it has always run indefinitely. The only bad machines I have taken on were two Apple XServes from 2009 with 24GB of memory that I got for free. Each had one bank of bad DIMMs, and after removal they ran for many weeks before I got around to turning them off. With 8 physical XEON cores running concurrently that was quite a few iterations. It took a week or so to fail memtest86. Then I repeated the failure (Another many days! What a pain...), then I replaced the bad DIMMs.
I had some motherboards which all consistently failed memtest86 after a few months of running, yet memtest86 did not find anything (I don't recall how much patience I had with run-time). I dropped from 4 to 3 banks of memory and they never crashed again. My ASUS motherboards with the same exact chipset always worked fine with 4 banks. Both used Crucial memory.
With Windows machines, I find that often they still pass the memtest86 for a couple of weeks test, but the machine remains unreliable under Windows. Sometimes an imperfect machine is suddenly reliable after a Windows release boundary. I had an issue before and during Covid with resolved on the fourth semi-annual Windows release - three releases with the problem! The same machine was suddenly rock-solid.
So if you reboot every day, or are happy saying "Oh, gotta reboot", and are not paranoid that some day the bad bit is going to be in your data instead of the instructions, then I would say to run memtest86 for at least a full day. In my experience most things are found in more than a few passes and less than a day. The information about the first pass being less thorough makes sense - I think it has always made it through the first pass or two. But a full day is not by any means conclusive. I am confident that a full month is, and I often compromise and run it for 2-3 weeks because I am impatient.
Finally, sellers of used computers typically swap things around, or even strip them into bins of parts then reassemble them based on what the customer wants, sometimes will little regard to static. I was told by one of them that the static issue was resolved sometimes in the 2000's and is not an issue any more. The truth is that static may wipe out a part, But most of the time it is just hot enough to mildly degrade a transistor only to manifest itself down the road. If you get a machine that has been running for a few years and nobody has taken it apart, chances are good that it will run roughly forever. Weak transistors are caused by impurities in the silicon crystal lattice, and the electric fields drive them to drift towards where they do the most harm. At higher temperatures, they drift faster. When there is a high current discharge (aka spark) they as well as the dopants that make the transistor a transistor are quite free to move around change the doping profile (Slope of the cliff). Picture a box of neapolitan ice cream with nice crisp boundaries between the vanilla and chocolate, now insert a little ni-chrome coil an inch in right on the boundary and heat it up to red-hot for a few seconds. What is going to happen? I had a laptop that I bought from a local recycler that would fail on memtest86 or crash every few days. I took it back and when I express concern about static (Looking at his process) he handed me another saying "Here, I have not touched this. It belonged to the IT manager of , that's where all of these came from and he gave me his last." That was in 2013. It is still running (2021), has not crashed yet. Almost worthless by today's standards, but it serves it's current purpose.