Unpredictable BSOD's with 8GB Ram

[pm72]

Hi,

Ever since I bought my new pc, there are random bsod's constantly occurring (regardless of what I'm doing).

 

I have narrowed it down to my Corsair Ram. The bsod ONLY occurs when there is 8GB fitted into my m/b (4x 2GB modules). There is nothing wrong with my RAM, memtests come out 100% clean, and I can have 4GB with any ram stick running fine.

 

Everything in bios and windows are at stock settings.

 

EDIT: I just want to clarify that the bsod's happen with anything more than 4GB of ram. I have the absolute latest updates for windows/bios/nforce etc...

The bios has the timings set on "Auto".

CPU-z give numbers that are also quoted on the data sheet for my RAM.

[RAM GUY]

With 4 modules I would suggest setting the memory frequency at DDR667 and set the memory Voltage to 2.0 Volts and set the NB/MCH/SPP Voltage to +.2 Volts as well and test the system with http://www.memtest.org. In addition, with some MB's (Mostly ASUS) you have to disable legacy USB in the bios when running any memory test.

[pm72]

So I'm effectively "underclocking" my memory?

Not what I paid for... :sigh!:

 

Will give it a go tonight.

[DerekT]

So I'm effectively "underclocking" my memory?

Not what I paid for... :sigh!:

 

Research prior to DRAM purchase would have given you this information.

 

Please research this thread:

 

http://www.houseofhelp.com/v3/showthread.php?t=64360&highlight=Unpredictable+results+QUAD2X4096+Gigabyte+X38-DS5

 

The issue is the memory controller and a population of all four banks at the full speed of a two bank run. This issue is across the board with both Nvidia and Intel chipset based boards, DDR, DDR2 and DDR3.

 

Keep in mind that often issues arise in the longer term. The issues seldom damage the DRAM. They damage the on motherboard memory controller which has a harder time keeping up with the demands of a four DRAM slot population being run as fast as a two DRAM slot population. Those who want to be secure in their system either purchase a single kit of the DRAM capacity that the four singles have or they move to a higher bandwidth DRAM and drop the bandwidth, which is what RAM GUY is advising. I also advise it as I have personally seen the issues that can and often do arise with a four DRAM slot population running at the full speed of a single kit speed.

[pm72]

Ooh thank you for that. ;):

Excuse my arrogance in the previous posts, but when i did research the memory, m/b etc, I really did not see anything along these lines.

 

Because my PC is still very new, would it be better/easier if I swapped my RAM with some other Corsair DDR667 modules? I still want the 8GB.

 

The only 4GB kit I found was:

"VS4GBKIT667D2 DDR2-667 (PC2-5300) 4GB Kit (2 x 2GB) 1.8v 5-5-5-15-2"

 

What do you think?

[DerekT]

Ooh thank you for that. ;):

Excuse my arrogance in the previous posts, but when i did research the memory, m/b etc, I really did not see anything along these lines.

 

Because my PC is still very new, would it be better/easier if I swapped my RAM with some other Corsair DDR667 modules? I still want the 8GB.

 

The only 4GB kit I found was:

"VS4GBKIT667D2 DDR2-667 (PC2-5300) 4GB Kit (2 x 2GB) 1.8v 5-5-5-15-2"

 

What do you think?

 

No matter what modules you install, you will have to drop the bandwidth. 1066Mhz modules --> 800Mhz, 800Mhz modules --> 667Mhz, 667Mhz modules to 533Mhz.

 

Now since you are running a 333Mhz FSB processor, then you must run with a minimum of 667Mhz sticks and you would not be able to drop the speed to a four slot population of 533Mhz as Intel DEMANDS a minimum 1:1 relationship with the CPU and DRAM.

 

Clearly you need to research that thread I posted. Please do so for the purpose of understanding it and study it, do not scan it. Then you will gain a better understanding of the issue. For you to think that dropping to a different DRAM speed shows you did not understand the reasoning.

 

The issue is NOT the DRAM. It is the on motherboard memory controller interfacing with twice the slots and is not able to do so at the full bore speed of the DRAM.

[pm72]

Hey DerekT,

I've become interested in what you've said in the other thread. Please help me understand a few things. (perhaps you can recommend me a site).

 

I can see that your MCH must be synchronised with the Ram's clock rates. So with a 1333FSB, you want 333.25 per ram slot = 667MHz (dual channel over 4 slots). Alternatively, I may overclock the FSB...I want to avoid that for now.

 

However, wouldn't you need to underclock less than 667MHz, because the FSB still needs to communicate with other hardware in the system?

 

You quote the example:

"1333 is to 800 as 1400 is to X or: " where X is the required DRAM speed. But that would not be true for 2 dual channels right? Ie. 1333:800 is not a stable ratio, so you cannot use it to determine what the DRAM should be set too.

If I said:

1333:667

X:800

That would imply I need to raise my FSB too 1599 for my MCH to be in sync with my ram?

 

Lastly, I was under the impression that motherboards underclock their ram/fsb in order for things to be synchronised? At least I thought the "Auto" functions do this job in BIOS.

 

I appreciate your patience at helping yet another "newbie" understand m/b architecture.

[DerekT]

Hey DerekT,

I've become interested in what you've said in the other thread. Please help me understand a few things. (perhaps you can recommend me a site).

 

I can see that your MCH must be synchronised with the Ram's clock rates. So with a 1333FSB, you want 333.25 per ram slot = 667MHz (dual channel over 4 slots). Alternatively, I may overclock the FSB...I want to avoid that for now.

 

However, wouldn't you need to underclock less than 667MHz, because the FSB still needs to communicate with other hardware in the system?

 

With regards to Intel Chipsets. There are numbers in the ratio that you can use. Less or more does not easily quantitatively apply if the ratio does not fit. When you have an Intel specified FSB, you alternatively have a MCH specified speed and latency to deal with the RAM in Ratio to that FSB.

 

For example:

 

200Mhz FSB, 266Mhz FSB, 333Mhz FSB and 400Mhz FSB

 

These are the Intel Spec FSB. Any FSB different than the above specified FSB's are not "IN SPEC" with Intel.

 

Now you have the Strappings/Ratio that effect the speed and latencies of the MCH.

 

When you populate more than two banks of DRAM, you change the MCH's ability to respond at the DRAM speed level with the latencies given in spec.

 

When you overclock the FSB, you also concurrently overclock the MCH. The overclock of the FSB <--> MCH also effects the speed of the DRAM as it is a part of the ratio and not locked out.

 

Now to your question. Other frequencies on different busses can be "Locked Out" on overclocking motherboards. PCI, ISA, AGP, PCIi-e, etc. are examples of frequencies that can and are locked out of the overclock when using a board capable of overclocking.

 

 

You quote the example:

"1333 is to 800 as 1400 is to X or: " where X is the required DRAM speed. But that would not be true for 2 dual channels right? Ie. 1333:800 is not a stable ratio, so you cannot use it to determine what the DRAM should be set too.

If I said:

1333:667

X:800

That would imply I need to raise my FSB too 1599 for my MCH to be in sync with my ram?

 

The equation allows you to solve for x and x is the FSB to set to for a more stable relationship between FSB <--> MCH <--> DRAM. Why are you adding the Dual Channel as a variable? Please explain to me how you come to such a conclusion? Please show examples and models or arithmetic supports of such a statement.

 

Lastly, I was under the impression that motherboards underclock their ram/fsb in order for things to be synchronised? At least I thought the "Auto" functions do this job in BIOS.

 

Some boards do, mostly the cheap, non overclocking value based boards will have some ability to downlock automatically, however they are not all that successful. But the better boards have the settings that allow you to do it with much better success. If you were to buy a cheap value based board and cheap value based RAM such as an ECS mainboard and a 266Mhz Core2 Duo with four sticks of value 667mhz DRAM and dropped it all in, very likely you would end up with your processor running at its speed, the DRAM running at 533Mhz in a 1:1 configuration automatically. If you did this in a higher end overclocking board, you would very likely end up with beeps and no post. Then you would have to remove two sticks, enter the BIOS, set the speed manually to 533Mhz, raise the memory controller voltage a notch or so, shut down. Insert the two other sticks and gain boot.

 

Check this site out:

 

http://www.overclock.net

 

They cater to helping the new to overclocking person and it is a very good site for asking questions. Many other more advanced overclocking sites are more arrogant to those who are questioning elementary issues.

 

Edit:

 

By the way, when you go to that site and ask your questions, keep in mind that you are speaking with regards to motherboards (Memory Controller) as the actual issue and not DRAM as the actual issue. Each kit of memory is in two and is supported as such. When you add two kits, you are effecting the Memory Controller's interface with the DRAM but not the DRAM itself. The proof of this is simple. That is why two sticks of 800Mhz DRAM run fine at 800Mhz and another set of two will also run fine at 800Mhz. But when you add them together, you change the dynamics of what? The DRAM? DRAM is passive, there are no operations created in DRAM. Just simple, Load and Access functions. So what dynamics are changed are external to the DRAM. Possibly that will help you see just where the issue lies.

 

You can post it as a DRAM question if you wish, you will just be informed as I have informed you though.

[pm72]

The equation allows you to solve for x and x is the FSB to set to for a more stable relationship between FSB <--> MCH <--> DRAM. Why are you adding the Dual Channel as a variable?

 

The dual channel isn't a varying variable, but don't you have take into account that with 4 banks (2 dual channels) your FSB needs to be different than with 2 banks (1 dual channel)?

For example (my opinion-please correct): A stable FSB ratio with 2 banks would be:

1333:800

For 4 banks it would be:

1333:667

 

Am I still wrong?

[DerekT]

The dual channel isn't a varying variable, but don't you have take into account that with 4 banks (2 dual channels) your FSB needs to be different than with 2 banks (1 dual channel)?

For example (my opinion-please correct): A stable FSB ratio with 2 banks would be:

1333:800

For 4 banks it would be:

1333:667

 

Am I still wrong?

 

Well, I can't say unless you show me mathematical proof or at least some intellectual model that would make sense. As it is, it makes no sense to me.

To my understanding, Dual Channel Mode allows an expansion of the data bus width. Thus this has to do with distance, not speed. So I can't see how you can quantify the ratio of speed and latency with distance when distance is not a part of the equation.

 

The reason for the equation is to allow for a stable timing latency and speed relationship between the CPU and concurrent components. The speed is dropped to allow for the relationship but there is no distance differential. Dual Channel Mode is a distance differential that allows for greater data width.

 

Your relationship is correct, just not for the reasoning of Dual Channel Mode.

[pm72]

ok.

 

Earlier you said, even if I used DDR667 ram I still need to underclock.

How do you explain why putting in 4 banks of DDR667 ram is not the same as using DDR800 at 667 speeds?

You highlighted that running 4 slots is the problem. But what is the relationship between FSB and number of ram slots? (this is equavalent to asking what is the relationship between FSB and number of dual channels).

[pm72]

k. Thanks for the help anyway.

[DerekT]

k. Thanks for the help anyway.

 

Let me try and explain this better.

 

Let's say you have a phone book of 1000 pages (DRAM). It takes a certain amount of time to go through the pages (DRAM SPEED) and a certain amount of time to turn a page (Latency). This is a created ratio and is a maximal of time to go through the pages and time to turn a page. Now let's change the parameters a bit. You are adding phone numbers to the book. You still have the same amount of time to go through the pages and turn the pages. If you are too slow, the page will not change and if you are too fast, the phone number does not get inserted. So, you have the proper times for both and the pages change and the data is inserted. This leads to data corruption and Blue Screens of Death if you do not fit the data in the page or turn the page at the proper time.

 

Now add 1000 pages to the book. But don't change any of the other parameters. The times to change pages for 1000 pages and the times to turn a page for 1000 pages is now 2000 pages but all set to the ratio and parameters of the 1000 page book. This is for purposes of comparison. Please do not think that this is a scientific explanation.

[pm72]

Thanks DerekT. I've seen your phonebook example in the other threads but that made it a bit more clear.

 

I will try underclocking my Ram speed. Do I need to manually set the timings as well? Or can I leave them on "Auto"?

[DerekT]

Thanks DerekT. I've seen your phonebook example in the other threads but that made it a bit more clear.

 

I will try underclocking my Ram speed. Do I need to manually set the timings as well? Or can I leave them on "Auto"?

 

You should be fine with the best timings of the DRAM as long as you use the voltages mentioned for those timings.

 

You can try and raise the voltage to the DRAM a bit and see if you can lower the timings as well. However, since you do not want to apply an overclock to the CPU FSB, you might not want to apply lower timings.

 

You are warranted up to and including 2.1v on that memory. So, you could set the DRAM to 2.0v and the timings to 4-4-4-12 and then run Memtest for two full passes. If you pass Memtest, you will be fine. Check CPU-z SPD and look at the timings for 667Mhz.

 

You can alternatively leave the timings to Auto as well.

[pm72]

Hey, my system appears fine after changing the DRAM to 667MHz.

 

I've set 2.01V in the BIOS but cpu-z reports 1.8V. So I don't know what's going on.

 

Now that everything is running at a 1:1, it should be ok to lower the timings as far as the system will allow me right?

4-4-4-12 was recommended, is that:

tCL-tRCD-tRP-tRAS?

 

I suppose CMD should be 2T?

[DerekT]

Hey, my system appears fine after changing the DRAM to 667MHz.

 

I've set 2.01V in the BIOS but cpu-z reports 1.8V. So I don't know what's going on.

 

CPU-z reports SPD (Serial Presence Detect) voltage. That is the JEDEC Standard voltage and is read only report. It does not show your actual Vdimm being used.

 

Now that everything is running at a 1:1, it should be ok to lower the timings as far as the system will allow me right?

4-4-4-12 was recommended, is that:

tCL-tRCD-tRP-tRAS?

 

I suppose CMD should be 2T?

 

Correct on both parts. Memtest prior to entering Windows whenever you make DRAM setting changes.

[pm72]

Ok so my system is running stable under 4-4-4-12. I ran memtests and prime2004 for 3 hours full stressing on cpu and ram and not a single fault.

 

However, on restart the pc exits windows then stops responding. When I do a hard turn off, the ram timings revert to their 5-5-5-18 timings again.

 

One more thing, the keyboard seems disabled just after POST. (Which means I can't access the memtest config menu etc).

 

These are minor things but I'm keen to know if there are any solutions.

[DerekT]

You might do well to contact your motheboard manufacturer for these issues. Possibly a BIOS flash to the newest version. Regarding the keyboard, if it is a USB keyboard, be sure to set "Legacy USB to Enabled" after memtest. So, disable Legacy USB for memtest and enable it afterwards.

[pm72]

You might do well to contact your motheboard manufacturer for these issues. Possibly a BIOS flash to the newest version. Regarding the keyboard, if it is a USB keyboard, be sure to set "Legacy USB to Enabled" after memtest. So, disable Legacy USB for memtest and enable it afterwards.

 

Ah yes that Legacy USB thingy - that fixed it ;):

 

Just wanna thank you again DerekT, your advice has been much more informative/useful compared to the PC technicians that sell these beasty hardware's!

Cheers to RamGuy as well! :biggrin:

[DerekT]

Sure thing :D:

 

By the way, you did perform a Load Setup Defaults and Save Setup Defaults prior to setting your BIOS? If not, document all your BIOS settings (Dig Cam works well) and then Load Setup Defaults, Save Setup Defaults and then manually enter your previous BIOS settings. See if this helps.

[pm72]

By the way, you did perform a Load Setup Defaults and Save Setup Defaults prior to setting your BIOS?

 

 

Yep, that's the first thing I did. :p:

[DerekT]

Don't restart. Shut down and press the power button. Are your settings saved? If so, use MSCONFIG. Start --> Run --> Type in MSCONFIG <Enter>. Choose Diagnostic startup. Shutdown and startup. Then restart. Does the system save settings?

[pm72]

Yes I did that before and the settings are saved. Everything loads up correctly. Haven't encountered that restart problem either.

 

Let's hope things stay this good for the next few weeks. (From experience, it usually takes a week for the pc to realise it's not running right :D: )

[DerekT]

Good stuff.