is it ok to run ECC memory with non ECC memory?

[hclarkjr]

i was running a stick of PC133 CAS2 ECC CRUCIAL with a stick of PC133 CAS3 micron and was getting lockups during gameplay only, system was fine till i played games, was there a conflict that caused this? thanx

 

[CubicZirconia]

Can you mix and match ECC and non ECC modules?

It's not a good idea.

 

[John]

Yes. All you need to do is disable ecc in the bios.

 

[hclarkjr]

that is wierd, i ran a ASUS A7V for almost 1 year with a ECC stick mixed with non ECC with no troubles at all, then recently i upgraded my motherboard to a ASUS A7V133 and get a 266FSB chip and that is when the fun started. was getting lockups and could not figure out what was wrong. somebody suggested i download a memory tester and test and low and behold the tester locked up! so lesson learned for me.

 

[zephyrprime]

Perhaps it's a matter of whether or not the MB is supports ECC. I would guess that non-ecc MB's can't even tell whether or not you have ECC ram. But if you try to use non-ecc & ecc in a mb, then you get problems perhaps?

 

[techfuzz]

John is correct, turn off ECC in your BIOS or in some cases a motherboard will detect the non-ECC memory itself and turn it off on its own.

Beware, don't mix unbuffered and registered memory together. This will cause all kinds of problems including but not limited to lockups and system hangs.

 

[lambasa]

You can, but it is not a good idea. This has nothing to do with being able to disable ECC in BIOS. ECC memory will generally have 9 devices per side while non-ECC memory devices have 8 per side (x8 devices). Modern chipsets require advanced memory initialization routines (in BIOS) that program drive strengths based on how many devices are present on the memory bus. Mixed memory (ECC and non-ECC) are not accounted for in this algorithm, so improper drive strengths can be programmed. Many of today's chipsets are not certified for mixed memory types for this reason, so if you are seeing system lockups, this could well be the problem.