4GB doesn't work while 2GB does

[imported_KuJaX]

Does the new Intel Core 2 Duo processors (1333mhz vs 1066mhz) change the memory criteria? For example, I just got done building an E6850 computer on Intel Battle Axe 2 motherboard with 4GB memory and it won't boot or show any picture. When I take out 2GB (so 2GB total) it will boot. The memory is DDR2 675 PC2 5400.

However, I helped a friend this last week build a machine with the Intel E6600 1066mhz with the same motherboard and same memory with 4GB and it worked fine. The only changes between the two are the processor, one was Intel E6850 1333mhz and the other is E6600 1066mhz, while the E6600 worked with 4GB DDR2 675, the E6850 DID NOT.

We also tested with 1GB all of the 4 DIMM's and all recognized and boot properly when a single (or two) DIMMS were used, so I know the motherboard is working properly.

Is this normal? Suggestions? Does the E6850 on the BattleAxe2 require DDR 800? I would hate to have to spend more money and purchase 2x2GB sticks to have them not work as well.

 

[Yellowbeard]

Are you allowing the bios to set the memory timings and speed or are you setting them manually? And, do you have the latest bios?

 

[JustaGeek]

I do not know how the motherboards' manufacturers address that problem, but 1066MHz CPU's have a FSB speed of 266MHz, so using the 1.5, or 3:2 Memory/FSB ratio (divider) it is very easy to accomplish 800MHz DDR2 speed.

Not so with 333MHz FSB - it requires the memory divider to be 1.2, and that cannot be translated into a simple fraction.

That's why I have chosen 325MHz FSB, for a simple divider of 16/13.

I guess the BIOS updates should resolve this issue - otherwise try running it at a speed above 800MHz, e.g. using the 4/3 divider, for the DDR2 speed of 888MHz.

If your memory can take it, of course. Otherwise, 667MHz, with the 1:1 ratio, might not be a bad option.

Check your bandwidth with SANDRA - if it is about 6000 MB/s wuth 667MHz, you're not losing too much of the performance anyway.

 

[imported_KuJaX]

Yellowbeard - I have tried setting the bios memory settings to "automatic" and then I also specified based upon what the "automatic" settings were when there are only 2GB in the system. Still no post or boot.

 

[Yellowbeard]

Originally posted by: KuJaX
Yellowbeard - I have tried setting the bios memory settings to "automatic" and then I also specified based upon what the "automatic" settings were when there are only 2GB in the system. Still no post or boot.

My only guess then is a bios bug with the new CPU. I realize your friend has done 4gb with his board and CPU. If it is not too much of a hassle, you may want to trade CPUs (as opposed to trading MOBOs) temporarily just to see if your board will run 4 DIMMs with his CPU. If your board runs 4 fine with his CPU, you'll need to contact the MOBO maker.

Also, Justageek had a good thought. Set your system to run 1:1 with 2 DIMMs (RAM at DDR667) and then see if those settings will boot 4 DIMMs.

 

[simplemind]

I was told, by an unreliable source, that a lot of P35 machines have trouble with 4 sticks of 1 meg., and not with two sticks of 2 meg. ..... go figure.
He also said, I'd be better off with PC5300 low latentcy than Pc6400 high latency. Someone shed some light on this, please!

 

[JustaGeek]

The performance of 667MHz memory rated at 3-3-3-8 is basically the same as 800MHz RAM rated at 4-4-4-12 (in terms of bandwidth).

 

[Acanthus]

Originally posted by: simplemind
I was told, by an unreliable source, that a lot of P35 machines have trouble with 4 sticks of 1 meg., and not with two sticks of 2 meg. ..... go figure.
He also said, I'd be better off with PC5300 low latentcy than Pc6400 high latency. Someone shed some light on this, please!

Not a hiccup here.

 

[JustaGeek]

You might have to increase the NB voltage to successfully run 4 DIMM's on some motherboards (might only apply to some memory modules.)

 

[Yellowbeard]

I have not seen any problems at all with P35 boards and 4 DIMMs. In fact, they are clocking 4 x 1gb better than any other board from my testing.

 

[imported_KuJaX]

Okay, got some DDR2 800mhz memory, and same thing. 1 or 2 sticks (1gb or 2gb) and it works fine, add in a third of fourth stick, and it doesn't work. I've tried playing a little bit with the voltage within the BIOS, but not sure if I am getting close. Any suggestions?

 

[Yellowbeard]

Originally posted by: KuJaX
Okay, got some DDR2 800mhz memory, and same thing. 1 or 2 sticks (1gb or 2gb) and it works fine, add in a third of fourth stick, and it doesn't work. I've tried playing a little bit with the voltage within the BIOS, but not sure if I am getting close. Any suggestions?

Yep.

My only guess then is a bios bug with the new CPU. I realize your friend has done 4gb with his board and CPU. If it is not too much of a hassle, you may want to trade CPUs (as opposed to trading MOBOs) temporarily just to see if your board will run 4 DIMMs with his CPU. If your board runs 4 fine with his CPU, you'll need to contact the MOBO maker.