PC freezes sometimes after installation of new memory sticks

[vsenapati]

The present configuration of my Desktop:
Intel Pentium 4 3.0 Ghz 800 MHzFSB 2 MB L2 cache
Intel D915GAV(onboard audio & video)
256 MB DDR PC3200
250 GB SATA HDD
Pixelview PlaytV@P7000
Sony DRU 810 DVD writer
Sony Combo Drive

The PC was running ok with the 2 X 256 MB DDR PC3200 memory installed as the following:
Memory channel A slot 0: 256 MB
Memory channel B slot 0: 256 MB
Recently I installed two matched memory of 512 MB PC 3200 in the remaining slots as following:
Memory Channel A Slot 1: 512 MB
Memory Channel B Slot 1: 512 MB
Nowadays, suddenly horizontal colour bands will appear on the monitor and the PC freezes. Control-Alt-Del does not work. I have to re-boot using restart button.
Is my installation not allright ? What can I do to identify whether the new 512 MB x 2 memory sticks are faulty ?

[Bjs]

A quick wizz about google will turn up memory checking program's that you can use to test memory for issue's .

Search for insert (a mini linux rescue cd = 50mb's) , burn with nero , use it ... packed to the nine's ... test memory , hd , and more ... I like the hd test ... sound's like it's about to take off (ps , it's bootable) .

As for the banding ... check you bios has made the change's ... some system's do have this issue with 1 gig of mem installed ... which mean's the pc is stuck , still only using the first 512mb installed .
(check control panel - system , see what it say's in general tab) , if it say's 512 , bingo ... go to bios to fix .

Colour banding may also require you to update the graphic's controler driver's ... they can have a habit of going stupid every now and then for no reason ... apart from ms update's making the occassional screwup .

[MOVIEGEEK]

Try CPU-Z to check PC specs:
www.cpuid.com/cpuz.php

and this utility to test memory:
http://oca.microsoft.com/en/windiag.asp

You might also check the motherboard website for a BIOS and chipset update.

BTW...Have you tried using just the 512MB sticks?

[vsenapati]

Today morning my Desktop again got stuck. I have removed the 2 nos x 256MB PC3200 and my Desktop is running with the 2 x 512MB PC3200 only. I am keeping the Desktop under observation and I hope the problem does not surface again. If it does then one or both 512MB PC3200 is faulty.

[redwudz]

Some motherboards are more picky about the choice of memory and it's position in the RAM slots. If you haven't tried this combination, it may work:

Memory Channel A slot 0: 256 MB
Memory Channel B Slot 1: 512 MB

Memory Channel A slot 0: 256 MB
Memory Channel B Slot 1: 512 MB

This is assuming all your memory checks out. Some motherboards don't like mixed sizes and occasionally if the memory is not exactly the same, it may have problems. This should have been covered in your motherboard manual.

You might look at it this way: If you now have 1024MB of memory, that's more than enough for video work. A few programs like Photoshop and some cam/cad programs can use more, and that is mainly to hold images that are being worked with in RAM. Encoders and transcoders use about 300MB at times, and since you have on board video, it probably uses about 25MB or thereabouts. With 512MB, it would be OK, but not much overhead. 1024MB is often the best size.

And if you have only one hard drive, adding a second drive may give you as much or more improvement as added memory. It will generally help throughput and helps when editing. I like a small HD for the boot drive and one or more for capturing, encoding or editing. They can be very large if needed. Partitions don't help much, as they still use the same controller.

[Cobra]

I would suggest MemTest86+:

http://www.memtest.org/

It's a great memory tester.

I suspect what could have happened here is that you have one of your 512MB modules in one dual-channel slot and a 256MB module in the other. Consult your motherboard manual to find out where to install modules.

Begin by installing the 2 x 512MB modules in the correct slots, and MemTest again. It will read out that you have dual-channel memory if all goes well. This will test your modules. Leave it to run for at least a few passes.

If there are errors, remove one module and test the other, then vice-versa to identify if one (or both) are faulty. If all goes well (hopefully!) then you can install your 2 x 256MB modules in the other ports and run MemTest again. If there are faults, pull all the modules and test the 256MB modules individually.

There is another possibility. I don't know if you know about memory timings (or latencies). This is how quickly, in terms of cycles, your RAM will operate. The most important of these is CAS (Column Array Strobe), which can be 2.0, 2.5 or 3.0 on DDR memory. The smaller the number, the quicker the memory (although 2.0 over 3.0 offers only a couple of percent boost in speed, it doesn't really matter so much). However, the RAM is much more stressed.

These timings are dictated by the "SPD Table" - the motherboard interrogates the RAM and find out automatically how quick it goes, saving you the hassle. Now, if your spangly new 1GB dual-channel kit has a CAS latency (CL) of 2.0 or 2.5, but your 256MB modules have a CL of 3.0, your motherboard may be reading the biggest modules and running at lower latencies than the older modules can cope with. This causes errors.

If you cannot solve the issue, try going into BIOS and changing the CAS latency to 3.0 and then memtest again. If you aren't completely sure what you are doing in your BIOS, read the manual - you can really do some damage in there.

Hope this helps!

Cobra

[vsenapati]

My PC has not got stuck yet after 24 hrs of using only the 2 x 512 MB PC3200 memory stick as mentioned earlier. I have come to the conclusion that these set of 512 MB memory sticks are not compatible with the set of 256 MB PC 3200. I think I will get these 256 MB memories exchanges for another set of 512MB PC 3200 and try it with the existing set of 512MB PC3200.I feel it will work allright. I will let you know what happened.

[Cobra]

Before you spend money, check out the memory timings on the 256MB modules! You could sort this issue with only one BIOS setting.

[Jeremiah58]

My PC has not got stuck yet after 24 hrs of using only the 2 x 512 MB PC3200 memory stick as mentioned earlier. I have come to the conclusion that these set of 512 MB memory sticks are not compatible with the set of 256 MB PC 3200. I think I will get these 256 MB memories exchanges for another set of 512MB PC 3200 and try it with the existing set of 512MB PC3200.I feel it will work allright. I will let you know what happened.

You have come to the correct conclusion.
Incompatibility is a common problem.
You can not go wrong if you exchange your 256 Mb memories with another set of the same 512 MB memories.

[TBoneit]

Did you look in your Mobo manual to see if it supports dual channel mode? If so it should also give proper slots for matched pairs to go in. Normal for best performance would be the same size and speed (brand too) in slot a and then slot b. IOW slot a's get 512 abd slot B's get 256 assuming they are matched.

[Cobra]

You have come to the correct conclusion.
Incompatibility is a common problem.
You can not go wrong if you exchange your 256 Mb memories with another set of the same 512 MB memories.

I am currently mixing and matching 256MB modules and 512MB modules, and I am getting on just fine - because my motherboard is correctly set up. It could be incompatibility, but it is much more likely to be that the modules are in the wrong slots, or the memory timings are too tight.

[Jeremiah58]

I am currently mixing and matching 256MB modules and 512MB modules, and I am getting on just fine - because my motherboard is correctly set up. It could be incompatibility, but it is much more likely to be that the modules are in the wrong slots, or the memory timings are too tight.

No, I didn't mean that kind of incompatibility.
I meant incompatibility due to different manufacturers.
I have mixed pairs of modules, 2 of 256 and 2 of 512 MB, set up in correct slots for dual channel and they work fine. But I was waiting couple of months until I found compatible memories to do the upgrade, because available memories did not work. I'm talking about the manufacturers.
The same thing happened on several computers of my friends here in Croatia and in the USA, so my first thought was incompatibility.

[Cobra]

No, I didn't mean that kind of incompatibility.
I meant incompatibility due to different manufacturers.

Ahh - sorry! Got the wrong end of the stick.

[vsenapati]

I had installed the two pairs ie 256 MB & 512 MB memory sticks in matching slots as per the manual of the mainboard but still I had compatibility problem. Yes, there should not have been a compatibility problem as per the manual but practically it did. I had planned to get the pair of 256 MB memory sticks exchanged for another set of 512 MB and try it out but the friendly neighbourhood computer dealer offered to take back those 256 MB memories. So, I could not test my PC with another pair of 512MB memories. Anyhow, my PC is running smoothly with the two 512 MB PC3200 memory sticks which I had got initially.

[Cobra]

Have you checked the memory timings? That could very well be the problem.

[Bjs]

In most normal case's , the 512's should be now in first bank set , and the 256's in remainer ... though you should check the reference of the mother board's manual for this setup ... which would be available from the mother board's manufacter's website .

As for that lockup ... timing's only play a minor role in how the system perform's ... I have never seen a pc using mixed timing's have any major problem's , apart from slightly slower than expected performance .

The one that can tell the difference is the bios setup on cas timing's , try the slowest cas setting first and see how that gose , if fine , adjust cas timing to next level and see how it gose ... when pc start's playing up again , you have reached the "no" zone , reset bios to previous cas setting's .

[Cobra]

Memory timings play only a tiny role in the performance of the machine, you're right. However, if the SPD table for the 512MB modules is CL=2/2.5 but the 256MB modules are rated at CL=3, and they're unhappy at CL=2/2.5 then you will definitely see lockups.

Trust me, I've seen it. That's why I'm saying that vsenapati should install the RAM as per the user manual for the motherboard, and try a CAS latency of 3. If that doesn't make a difference in MemTest86+ then it's something else. If it does, brilliant - no more problem!