Dual Channel memory problem

[dcosmopolitan]

I am having Intel DG31PR with Intel Core2Duo E7300 processor.

I have 2x2GB DDR2 800MHz Transcend memory.

both are 800 MHz but when they operate together the bios and CPU-Z showing only 667MHz.,..

i bought the same two model from Transcend JM800QLU-2G but still there is timing difference between the two...am i getting 800MHz or 667 really...can it cause trouble to my motherboard or memory...should i try getting the same memory ie the older model with same name,,,,

 

[Mongox]

Are you saying that when you run the system with only one module in place, that module A comes up as a 800 and stick B comes up as a 667?

If that is the case, then when run together, both modules will run at the lower speed, because your system will slow down the faster one to match the slower one - just as though you had added a single new module to pair with an older, slower module.

Normally, when you want dual-channel compatibility, you want to buy a "matched" pair of modules, designed and marketed for dual-channel use. The Transcend website says " Chipset: Intel G33 MODULES MUST BE ORDERED AND INSTALLED IN PAIRS for Dual Channel mode." When sold as a pair, both modules are tested AS A PAIR to be sure they have the same exact characteristics.

Buying a pair of modules packaged together is also often less expensive. If you had bought this memory at NewEgg, each single module would have cost $29.99. NewEgg doesn't offer this brand as a dual-channel pair, but you can get a Patriot pair on special for $50.
http://www.newegg.com/Product/Product.aspx?Item=N82E16820145238

A couple things to double-check. Try each module by itself to see its characteristics. If one comes up different than the other, they won't work together except at the lower specs. Check the RAM being delivered by the motherboard - it should be 1.8V - likely the standard.

You don't mention how much and what type of RAM you're replacing on this M/B.

Respond and answer these quiestions and we'll see what can be done.

 

[dcosmopolitan]

when both memories are operating individually they show 800 MHz....actually i bought same models from Transcend one is older and one is new with following timings:

older : 5-5-518
newer: 6-6-6-18

although they carry same model no. why thr is timings diffrence...

as per my knowledge older one is fast!! but why would they decrease performance timings in newer model?

u tell which model is better i will get same stick then....

i m posting images of slots and memory from CPU-Z

hope that cl;ears evrything u wanna know....

 

[Mongox]

OK, I think you're running into a problem because they aren't "matched" dual channel memory. If you can return one or both - I would do so and get a pair of modules - sold together.

As for which is better - the lower the CL number, generally the faster the RAM.

I get the impression you're not in the US. What sources do you have for buying RAM? If you point me to a website where you got it, someone here may have suggestions for a different brand.

But right now, I'd see if you can return BOTH of the modules.

 

[dcosmopolitan]

yes they arent matched even they are from same maker with same model....

ii can change one module u suggest what would be better option out of these two??

(5-5-5-18) + (6-6-6-18) @ 667 MHz

or 2* (6-6-6-18) @ 800 MHz

i m having first combination now i can get the second combi by returning the older one...i cannot get the older model ...I am from India.

 

[Mongox]

The "old" memory has faster specs.

I would return the older one and get a 2nd "new" one. This way, your memory will be matched.

The best solution would be to return the new one and get another "old" one - but that is not possible.

Normally, many here would suggest it's better to have 2 modules running at 5-5-5-18 & 667MHz than 2 modules at 6-6-6-18 & 800. You can do that currently, but with un-matched pair.

Return the "old" memory, get another that exactly matches the one you keep. Once you have that, you may find that you can adjust your BIOS to run the new pair at 800MHz and 5-5-5-18 - maybe! But even at 667, it's best to have matched pair.

 

[dcosmopolitan]

what matter more in performance? timings or frequency?

should i get another "new" one or keep the existing new+old at 667?

 

[Mongox]

Return the "old" memory, get another that exactly matches the one you keep. Once you have that, you may find that you can adjust your BIOS to run the new pair at 800MHz and 5-5-5-18 - maybe! But even at 667, it's best to have matched pair.

See my last post for my suggestions - one thing I wouldn't do is to keep the current new+old - since I don't think you can ever run dual channel - and that makes more difference than anything else!

Timings is more important than frequency - within one step of each other. That is, calculations show that 667 @ CL=5 is faster than 800 @ CL=6. But I doubt that 533MHz @ 4 is faster than 800 @ 6...

But you don't have the option of dual channel memory of 667 @ CL=5 I don't believe - since you cannot get another "old" module. But... you can always drop the 800 down to 667 and get CL=5 - but the pairs have to match.

 

[rand_79]

can you just manually set the memory to 800mhz in the bios when they are installed as a pair? vs having the motherboard autodetect and auto set them?

it might be that easy.

 

[Mongox]

Rand, the real problem is that since the memory isn't matched, it likely can't ever be run as dual channel. Since I don't know of any boards which allow adjustments to RAM speeds to individual modules, can't be done. I've seen a few BIOS that seem to allow adjustment to banks, but not modules.

 

[dcosmopolitan]

ok so i will be going for 800MHz @ CL6 cos thats the only option avail...thanks for the help guys...

 

[rand_79]

you can manually set the ram to run at any speed.. it might not boot but you can set it ...
It could be the SPD settings are just wrong on the chip and by manually setting them to run at 800 they could be fine.

 

[funguseater]

You could also manually set the timings to 5-5-5 18 but leave it at 400 and see if the "new" ram will pass memtest. Alot of times companies will state specs just to be on the safe side.

 

[Mongox]

Again, with a pair of modules that are not matched, like these are not, the chances of running dual channel are strictly experimental. Anything that can be adjusted, such as lowering the timing or manually setting the speed, is best done on a matched pair. And while he can still return the "older and faster" module and replace it with one that will create a matched pair, that's the best advice.

 

[dcosmopolitan]

I am now running two modules of CL=6 @ 800 MHz. Just let me know out of these two which is faster and recommended?

1. One CL5 800MHz module + 1 CL6 800MHz module = 667MHz

By dcosmopolitan at 2009-09-20


2. Two CL6 800MHz module = 800 MHz

By dcosmopolitan at 2009-09-20

 

[dcosmopolitan]

which config or pairing is recommended and faster out of the above two configs.

 

[Mongox]

I'll try again!

1. One CL5 800MHz module + 1 CL6 800MHz module = 667MHz CL=5 -- This is your BIOS's response to finding un-matched RAM modules attemping to run them as dual channel. Since it cannot match them at 800MHz, it drops down to 667 speed which it finds a match in CL specs. This is likely NOT a stable configuration - you should NEVER use un-matched memory modules in a pair of dual channel slots.

2. Two CL6 800MHz module = 800 MHz CL=6 -- The system finds a pair of perfectly matched modules and rewards you by showing them in 800MHz mode. Since they are matched, you can easily change them to 667MHz mode if you want - so you'd have the exact same specs (667/5) that you have above.

Again, since you cannot get two modules with 800/5 specs, the best choice is two with 800/6 specs. ANY 800/6 RAM will run at 667/5 - so which is faster is not an issue. As for whether 800/6 is faster than 667/5, it's a complicated calculation and people will disagree about the results. But again, no one will tell you to use un-matched modules as dual channel memory.

1. One CL5 800MHz module + 1 CL6 800MHz module = 667MHz << BAD - DO NOT USE because memory modules do not match.

2. Two CL6 800MHz module = 800 MHz << GOOD - Memory is matched and should be stable.

3. Two CL6 800MHz module @ CL=5 << BEST - but not an option to you unless you return ALL your modules and replace them with faster model or faster Brand of RAM.

Your BIOS apparently has, among others, the following choices regarding RAM:

SDRAM Frequency
in Advanced > Chipset Configuration or Advanced > Memory Configuration
• Auto
• 266 MHz
• 333 MHz
• 400 MHz
Allows override of detected memory frequency value
If you wanted to, you can manually reset choice 2 above to 667MHz and see you have CL=5 automatically.

SDRAM Timing Control
in Advanced > Chipset Configuration or Advanced > Memory Configuration
• Auto
• Manual – Aggressive
• Manual – User
Defined
Auto allows timings to be programmed according to the
memory detected.
Manual – Aggressive selects the most aggressive user
defined timings.
Manual – User Defined allows manual override of
detected SDRAM settings.

You can experiment with the CL and other settings with the above BIOS option and others. Your pair of matched RAM (choice 2) may run fine at 800MHz and CL=5 - you have to try it and see.

DO NOT KEEP UNMATCHED RAM (CHOICE 1)

 

[dcosmopolitan]

Thanks a ton for the most correct explanation!!

now i get it and i am going to keep two CL6 800 modules cos as usaid unmatched modules are unstable..

now my motherboard is Intel DG31PR. and it doesnt giv me an option in BIOS like u mentioned above to change the timings or FREQ... it is set to AUTO at 800 CL6.

now can i use any software to change the 800CL6 to 667CL5 or even 800CL5.

if the module is CL6 will it be able to run @ CL5.

is it safe to modify the values when ur BIOS doesnt permit?

any other software by which i can set these values manually without damaging the hardware?

 

[Mongox]

Thanks a ton for the most correct explanation!!

now i get it and i am going to keep two CL6 800 modules cos as usaid unmatched modules are unstable..

Great!

now my motherboard is Intel DG31PR. and it doesnt giv me an option in BIOS like u mentioned above to change the timings or FREQ... it is set to AUTO at 800 CL6.

The quotes I had above came from the Webpages on your motherboard.
http://www.intel.com/Products/Desktop/Motherboards/DG31PR/DG31PR-overview.htm
Your motherboard manual:
http://download.intel.com/support/motherboards/desktop/dg31pr/sb/d9918201_en.pdf
This is where I found them - in the Glossary of BIOS terms. This may be general terms and not specific to your board.
http://www.intel.com/support/motherboards/desktop/sb/cs-020304.htm
You should download everything there and save all the webpages so that you can easily refer to them. Do not update your BIOS unless you think it will do something good for your system - but you can save the updates, if any, for later use if needed.

now can i use any software to change the 800CL6 to 667CL5 or even 800CL5. - if the module is CL6 will it be able to run @ CL5.

Be careful here. If the module is CL6 @ 800 then it is also CL5 @ 677. ------ But you have to experiment to see if the good pair will perhaps run well at CL5 @800. [/quotemsg]

is it safe to modify the values when ur BIOS doesnt permit?

Yes, normally it is fine. Any very different settings may have to be tested. But if your system seems to work OK with changing CL to 5 at 800MHz, it's probably OK. If you make a setting that is not allowed, usually the motherboard will 1)not boot at all 2)not complete POST or 3) not enter Windows. If that's the case and you cannot get into the BIOS to change the settings, then you use the motherboard jumper to CLEAR CMOS and reset it.

any other software by which i can set these values manually without damaging the hardware?

The software which I use to set these values is designed specifically for my board - and I don't like it very much. I'm not sure if there is any general software. I set the values in BIOS, then boot and test the changes. I use the programs CPU-Z and CPUID Hardware Monitor available at www.cpuid.com and also Prime95 available at www.mersenne.org to test the memory settings. A test only for memory errors is memtest86 which is run from a CD or a diskette - this you use when you think memory might be bad.

 

[dcosmopolitan]

i already have these motherboard manuals and i have gone through them.. mine is very basic mainstream motherboard so it wont supoprt adv features

i think i wont risk experimenting and will run the modules @ either 800MHz/CL6 or 667MHz/CL5

thanks for all the help!!