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Troubleshooting RAM problems

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huddy
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Troubleshooting RAM problems

Post #1 by huddy » Tue Jul 02, 2013 12:40 pm

Failing RAM is not uncommon and most PC owners have encountered memory problems at some stage. Symptoms could include random system restarts, unexpectedly freezes and even the dreaded Blue Screen Of Death (BSOD).If you have such problems, then you are right to suspect faulty RAM but it may not be a full gone conclusion.

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If you have recently upgraded your RAM only then this is most likely to be the source of your problem. However, diagnosis is a little more complicated where one or more system components have been installed at the same time, such as a full system upgrade which in most cases is unavoidable. Even worse scenario is when you encounter these same problems when you’ve changed nothing.

If your PC is experiencing such problems, then you are right to suspect faulty RAM but it may not be a full gone conclusion. So here are a few simple procedures for you to verify if your RAM is functioning correctly and is indeed faulty.

Check Compatibility

Nowadays, it’s technically impossible to install the wrong type of RAM into your motherboard. For example, the orientation key deliberately prohibits you installing DDR2 into a DDR3 motherboard and DDR2 into a DDR motherboard etc. However, if the RAM fits it doesn’t’ necessarily mean it’s compatible and some motherboards are rather fussy about some brands of RAM. Although this is unlikely, check the motherboard manual or website for recommendations.
Most motherboards have a recommended RAM lists or QVL (Qualified Vendor List). This is to say; that the RAM they list has been tested and approved for your motherboard.

Make sure the RAM you are using will run at the effective bus speed of your system.

Bear in mind that some older motherboards require the largest RAM module to be installed lowest bank. Others may require certain banks (see dual/triple channel memory below) or all banks to be filled. It’s worth checking this out.

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Different generations of RAM showing the slight deviations with the orientation key

Check Contacts

Check that the RAM is properly seated and is making good contact. Even on uninterrupted systems, RAM can become dislodged if the PC has been moved.
Make sure the contacts are clean. Try a little denatured alcohol and lint free swabs to clean the contacts and wait to dry.
Make sure the slots are free from dust. Use a very soft unused paintbrush to get deep into the slots to remove trapped dirt, and then vacuum using the plastic attachment. You can also use compressed air.

Memtest86+

Run Memtest86+ to determine if your problem is RAM related, rather than PSU, Hard drive etc.. Memtest86+ is a superb free utility that performs a series of tests to check memory stability. If there are any problems with your RAM or addressing RAM, then Memtest86+ will tell you.

However, notice I choose the words “RAM related” rather the faulty. If Memtest86+ reports an error or errors then this doesn’t necessarily mean the RAM is faulty, it just means that the system can’t use the RAM for some reason. It might be the BIOS settings are incorrect so they could be operating at the wrong speed (see check settings above). It could be faulty memory controller or system bus.

Nor can Memtest86+ tell which module or channel is faulty if that were the case. In order to find if the RAM is actually faulty and indeed which modules, you’ll need to perform some further diagnostic tests (See “One at a time Please” below).

Run Memtest86+ only when you have exhausted all other basic possibilities as previously mentioned. It would prove rather counterproductive running Memtest86+ for 2 hours when all you needed to do was re-seat the RAM for example.

Memtest86+ runs directly from a live bootable CD or DVD, so Windows isn’t necessary. Simply download and follow instructions on how to create and use the utility. Leave Memtest86+ running for a few hours but keep an eye on the first five minutes or so as any faults are likely to be shown then. Any faults will be shown in red as shown below.

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Memtest86+ is great for detecting RAM related problem but it doesn’t mean your RAM is faulty

Clear the CMOS

In most cases, it’s a good idea to clear the CMOS when diagnosing all stability problems. This will mean any overclocking you may have applied will be discarded. Make sure you have made a note of the changes you have made so you can re-apply them later when you have corrected the problem. At factory settings, your memory setting will revert to AUTO and can sometimes fix RAM related problems so run a quick test afterwards to make sure.

Check the RAM settings

Verify your RAM is running at the correct settings. If you are fortunate that you can access Windows, then CPU-Z is a good utility to identify your current settings. If you can't get into Windows then you will have to obtain the memory settings in the BIOS.
Check these settings against the against the manufacturers’ recommendations. Visit their website for recommended voltage (VDIMM), timings (Latency) and Frequency (Bus speed) etc.

If the AUTO setting doesn’t work, then you may need to make some manual adjustments in the BIOS. This maybe the case if you have purchased ultra-high frequency RAM, often referred as “Overclocking RAM”.

Warning - Be extremely careful when changing BIOS settings. Make sure you have verified the settings you are about to change. Setting the VDIMM too high for example, could permanently damage your system.

You can always undo any changes at any point by resetting the CMOS back to factory settings. This normally involves using a jumper to short two pins. Again, please consult your motherboard manual.

Remove all the RAM
Sounds daft but If you have an internal speaker or POST LEDs, then remove all the RAM and power on the system which will then fail. The Power on Self Test should complain that no memory is installed which is a good thing because it means the motherboard is functioning correctly. In which case, you can now start to test the RAM. If you don't get any errors, then the problem is more likely to be a PSU or motherboard problem.

Swap if you can!

If you have the access a similar specification PC then you could try the RAM in that machine. Be sure the RAM requirements are the same otherwise it won’t work. If the RAM fails in another machine, then your RAM is almost certain to be faulty, otherwise it could be your motherboard/CPU.

Likewise, if you have access to similar RAM of the same specification, you could swap the RAM for known working modules.

One at a time please

If you have exhausted all basic checks and Memtest86+ shows errors, then you’ll need to do a little more detective work.
Try running your system with one stick of RAM at a time and try each stick in different slots, going through each possible combination until you can pin-pin the cause.

Don’t worry if your system uses a dual or triple channel memory controller. Installing a single stick only disables this function. The chances are the system will run a little slower but should still function.

Write down a test plan on how you going to test each combination. Not only will this help you keep track of your tests but also highlight a common factor in the test. Use Memtest86+ (see above) to test each combination.

If a single RAM module fails in all slots, then it’s almost certainly a faulty RAM module. In the example below, STICK 1 fails in both slots.

STICK 1 SLOT1 = Fail
STICK 1 SLOT2 = Fail
STICK 2 SLOT1 = Pass
STICK 2 SLOT2 = Pas
s

If the RAM stick works in one slot but not another, then the RAM is okay but more likely to be a faulty memory controller. This could be CPU or Motherboard depending on the platform. In the example below, both sticks work in SLOT1 but both fail in SLOT2.

STICK 1 SLOT1 = Pass
STICK 1 SLOT2 = Fail
STICK 2 SLOT1 = Pass
STICK 2 SLOT2 = Fail


From this deduction, you can isolate the problem.

Updating the BIOS

Check the motherboard manufactures for any known issues with the RAM you have installed. Sometimes updating the BIOS can resolve many issues so it may be worth doing this anyway. Check with the motherboard manual for BIOS “Flashing”.

Dual/Triple Channel Memory

Dual and Triple channel memory theoretically doubles and triples the memory bandwidth respectively so installing the modules into the wrong memory banks shouldn’t cause too many problems but you may have a hit on performance. The System normally indicates if dual or triple memory channel mode is enabled during the POST sequence during the boot process.

If you have a dual-channel memory capable motherboard, then check you have installed equal [see note below] RAM modules in multiples of two in to the same memory bank normally indicated by the same colour scheme. i.e. blue or white. These are normally slots 1 and 3 or slots 2 and 4.
If you have a triple-channel memory capable motherboard, then check you have installed equal [see note below] RAM modules in multiples of three in to the same memory bank. Again, like dual-channel memory, these are indicated by the same colour scheme. i.e. blue or white. These are normally slots 1, 3 and 6 or slots 2, 4 and 6 if there are six slots.

Note – RAM modules should be identical in specification. i.e. each module should have the same capacity, frequency and latency when being installed into a dual/triple channel capable motherboard.

If you are using mixed RAM then you’re likely to have stability issues. If the capacities are different then you’ll need to replace as this can’t be altered. If the frequency and latency (timings) are different, then you may have to manually change the memory settings in the BIOS so that all modules operate at the slowest frequency RAM and/or the loosest timings to them working. This can be hit and miss. However, you should be using dual/triple channel memory kits which guarantees all modules are of equal specification.

Common known RAM faults

General Protection faults, page faults and exception errors – If you get these errors or any other fatal error message after a RAM upgrade it is likely to be RAM related.

Error in RAM Size – Size of new RAM is misrepresented in the Power-On-Self-Test (POST) RAM check. This could be down to a number of reasons but likely cause is incompatible RAM. It could also be result of exceeding Ram capacity that the motherboard supports.

Computer shows blank screen upon boot-up – Usually result of poorly seated RAM or during install another expansion card was dislodged.

Computer Bleeps during start-up after installing new RAM- The Power On Self Test (POST) has detected an error. If you have only changed your RAM then the BIOS is reporting an error with the RAM. Cross check the series of bleeps with the motherboard manual for likely cause.

Computer Freezes, or Blue Screen of Death (BSOD) – Although not always RAM related this is often the result of failing or failed RAM. Check the diagnostic procedures above.IRQL_NOT_LESS_THAN_EQUAL is normally related to memory problems I’ve found.

POST doesn't say that Dual/Triple channel memory is enabled? – See above

What to do if the RAM is faulty

If your RAM is under manufactures warranty then you can arrange a replacement with them by raising an RMA (Return Merchandise Authorisation). This is the process whereby the produced is returned to be either repaired or replaced. Contact your retailer if the purchase was quite recent otherwise visit the manufactures website for details.

If you have dual or triple channel kits, you’ll be asked to return all modules. The RMA process can take some times as products are normally tested before replacement is dispatched.

If your RAM is out of warranty than you are lucked out. You’ll need to buy replacement RAM. Make sure you purchase compatible RAM.

Useful Links

Memtest86+
CPU-Z - Provides memory module information such as frequencies, timings, voltages etc.
Corsair
OCZ
GeIL
G-Skill
Kingston memory
Patriot




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huddy
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FAQS

Post #2 by huddy » Fri May 16, 2014 3:28 pm

I am looking to upgrade the memory in my PC but I'm hearing/reading different things about it.. I currently have 4GB ram but would like to make it 8GB or even 12GB, so I am wondering what’s best really. Here is my setup:

AMD Phenom II X4 Quad Core 955 Black Edition "125W Edition" 3.20GHz (Socket AM3) - Retail
PC Power & Cooling Silencer 750 Quad-Crossfire PCI-E 750W Power Supply
Gigabyte GA-MA770T-UD3P AMD 770 (Socket AM3) PCI-Express DDR3 Motherboard
OCZ Platinum 4GB (2x2GB) DDR3 PC3-10666C7 1333MHz Dual Channel (OCZ3P13334GK)
Western Digital Caviar Black 500GB SATA-II 32MB Cache - OEM (WD5001AALS)
Scythe Mugen 2 CPU Cooler (Socket 478/754/939/940/AM2/LGA775/LGA1366)


Can I just add another 2x2GB DDR3 1333Mhz RAM and then have 8GB? Someone told me I need to replace my entire ram, another person said I need to run 3 sticks of RAM ... so I don’t know, any advice please?


Installing RAM in multiples of three would suggest a platform that uses a triple channel memory controller, such as the Intel X58 platform. Since your system uses dual channel memory this isn’t the case but it does require you to install RAM in pairs so you should be fine adding another 2 x 2GB. Ideally, your new RAM should match the specification of the existing RAM, i.e. same speed and latency. In your case, PC3-10666 with a latency of CL7.

If however, you happen do happen to buy slower frequency or latency RAM, then you’ll have to make necessary adjustments in the BIOS to make sure that all the RAM runs at the same speed and latency as that of the slower RAM . Otherwise you may experience unexpected system crashes.

For example, if you install new RAM with a latency rating of CL8 where CL7 is already present, then you will have to run your CL7 RAM at the slower CL8 latency, because the CL7 timings are too aggressive for the CL8 modules. Likewise, with the frequency you will need to set the DRAM frequency to that of the slowest.


I currently have 4 x PC2-4300 (266MHz) 512 MB DDr2 in my machine and want to increase it.

There's isn't much choice of 266MHZ, is it ok to put higher "spec" of RAM in to the exisitng system or will it cause problems?

Thanks
.


Installing higher frequency RAM is fine providing it's the same type i.e. DDR2. so in your case, installing PC2-6400 would be fine but you may need to make a few adjustments in the BIOS...

The system can be adjusted so that the RAM can operate at a different and higher speed than the operating bus speed (Asynchronous memory) by either changing the memory frequency or the memory divider in the BIOS to the desired speed.

You'll need to set the correct frequency or change the memory divider depending on the current bus speed. For example, if your current operating bus speed is running at 266MHZ, Then you will need to set the frequency to 400MHZ (800MHZ effective) or set the divider to 4/6 depending on your BIOS. A divider of 4 /6 is (266 / 4) * 6 = 400MHz (800MHz effective).

Be careful though, selecting a frequency or divider higher than the specification of the RAM is effectively memory overclocking and may cause stability problems.


That's great, Am I correct in thinking that the lower the latency timings the faster it will be be? i.e. CL5 (5-5-5-15) is quicker than CL7 (7-7-7-20)?


Correct. However, although higher frequency RAM is at the expense of the latency, having higher frequency RAM is of greater benefit to performance over tighter timings which are insignificant.

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ALXAndy
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Re: Troubleshooting memory problems

Post #3 by ALXAndy » Wed Jun 04, 2014 11:27 am

The most important thing when mis-matching ram is that the ram all has the same voltage, or, as close to it as possible. I wouldn't worry so much about the timings but the voltage. If one set of ram runs at say 1.5v and the other runs at 1.8v you could easily run into issues.

The timings can be slackened, but 1.65v ram for example does not like being ran at 1.5v and will be unstable. In this scenario you could simply run the 1.5v ram at 1.65v and this would usually be fine.

The reason I say this is because I have some OCZ 1866mhz memory and it needs an eye watering 1.9v.

One other thing I wanted to add... Sometimes ram issues lead back to bent pins on the socket. I've seen this many many times. Ram failing tests, ram being incorrectly reported in bios and so on. Usually always caused by bent pins in your socket so always check them if you are having ram issues.
Alienware Area 51 2014.
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