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Electronics => Projects, Designs, and Technical Stuff => Topic started by: Aigor on May 09, 2017, 03:48:07 pm

Title: Ram computer tester
Post by: Aigor on May 09, 2017, 03:48:07 pm
Hi, i'have an idea, could be possible build a standalone pc ram tester?
My friend own a computer lab, he have a lot of simm and today i start to think about ram standalone tester.
Could someone point me to some info about info on how dimm work?
Or, someone has same idea?

many thanks
Title: Re: Ram computer tester
Post by: bktemp on May 09, 2017, 04:22:20 pm
Hi, i'have an idea, could be possible build a standalone pc ram tester?
I assume you are talking about modern DDR3/DDR4 memories?
It is possible, but very difficult.
Quote
Could someone point me to some info about info on how dimm work?
If you have to ask such questions forget it.
DDR3/4 operate at >1GHz. That requires carefully designed pcbs with at least 6 or 8 layers.
In addition to that to need a processor or FPGA that drives the memory at such speeds with the correct timing. Even if you are able to build such a device, it will be really expensive, because you need to to a lot of tests to verify your timing, otherwise you won't know if the RAM is bad or the timing of your tester is incorrect.
Title: Re: Ram computer tester
Post by: Nusa on May 09, 2017, 04:38:54 pm
Such things exist commercially and are easily found in a search, but I wouldn't bother.

I'd just use a open frame PC with a motherboard that supports the RAM in question. Use a bootable flash drive with some of the many RAM testing programs that are available and you're good to go.
Title: Re: Ram computer tester
Post by: CJay on May 09, 2017, 04:43:03 pm
Such things exist commercially and are easily found in a search, but I wouldn't bother.

I'd just use a open frame PC with a motherboard that supports the RAM in question. Use a bootable flash drive with some of the many RAM testing programs that are available and you're good to go.

Don't know an awful lot of the tech bits around DDR3/4 etc but wouldn't a thorough test in such circumstances require a board that'd 'max out' the memory speed?

I know the commercial RAM tester I had used to be able to push the RAM to its limits and over which was a great way to ensure reliability in high end systems but we're back in the 486 and Pentium MMX era...
Title: Re: Ram computer tester
Post by: daqq on May 10, 2017, 06:09:12 am
It is possible, but given what speeds current memories work with and the requirements of the modules themselves, it would be very expensive to develop.

The simple solution is to use a PC with a motherboard that supports your particular memory type and make a software solution that would stress the memory.
Title: Re: Ram computer tester
Post by: james_s on May 10, 2017, 08:09:28 pm
I have an old DSI RAM tester, the thing is fantastic for working with vintage gear. Pop in a SIMM or DIMM and it tells you the capacity, tests the speed and then it can run a full test. I don't think mine will work for anything beyond the Pentium II generation but surely more modern machines exist.
Title: Re: Ram computer tester
Post by: David Hess on May 11, 2017, 11:05:39 am
Don't know an awful lot of the tech bits around DDR3/4 etc but wouldn't a thorough test in such circumstances require a board that'd 'max out' the memory speed?

It requires more than that.  Besides timing, the supply voltages should be swept.  Good floating gate memory programmers do this also to verify programming margin.

As far as how to do this economically, a PC motherboard with one of the good memory test applications is probably the best way and I would deliberately run the memory at its lowest specified voltage and maybe 10% faster than its rated speed.  Some motherboards support a +10% clock speed mode for burn in testing which would be ideal.
Title: Re: Ram computer tester
Post by: CJay on May 11, 2017, 11:10:12 am
Don't know an awful lot of the tech bits around DDR3/4 etc but wouldn't a thorough test in such circumstances require a board that'd 'max out' the memory speed?

It requires more than that.  Besides timing, the supply voltages should be swept.  Good floating gate memory programmers do this also to verify programming margin.

As far as how to do this economically, a PC motherboard with one of the good memory test applications is probably the best way and I would deliberately run the memory at its lowest specified voltage and maybe 10% faster than its rated speed.  Some motherboards support a +10% clock speed mode for burn in testing which would be ideal.

Nowhere near as simple as it used to be, I can't imagine many aftermarket/'refurb' places going to that trouble unless it can be done programmatically?
Title: Re: Ram computer tester
Post by: David Hess on May 11, 2017, 12:04:29 pm
It requires more than that.  Besides timing, the supply voltages should be swept.  Good floating gate memory programmers do this also to verify programming margin.

As far as how to do this economically, a PC motherboard with one of the good memory test applications is probably the best way and I would deliberately run the memory at its lowest specified voltage and maybe 10% faster than its rated speed.  Some motherboards support a +10% clock speed mode for burn in testing which would be ideal.

Nowhere near as simple as it used to be, I can't imagine many aftermarket/'refurb' places going to that trouble unless it can be done programmatically?

The best automatic testers do all of this but the right PC motherboard when set to "burn in" mode and with the RAM supply voltage set to minimum will work.  The slowest part of the test is waiting for the memory test to finish.