Rambus : ECC / Non-ECC Question. HELP!

[2Pac]

Hi, I've got the following question/problem

I'm using an Intel 850GB motherboard with a 1.7Ghz p4


Now, I had two 64 Mb Samsung PC800 Non-ECC RIMMS

I've just purchased two 256 Mb Samsung PC800 RIMMS from a computer shop....now I've realised that they are ECC modules.

I'm pretty sure that there aren't any NON-ECC 256 Mb modules available from that shop, so taking them back is not an option.


The way I have the RIMMS inserted is:

Pair 1 = two 256 Mb
Pair 2 = two 64 Mb

What I wanted to ask is, do I have to specifically set some option in the bios to disable ECC features, which I don't want because it'll affect performance (probably about 3%. but still...not what I want). If so....how? (for this board)

I've read somewhere, that if ECC and Non-ECC memory is used in a p4 system, the ECC features will automatically be dropped.

However, I wanted to know if by disabling the ECC features...if there'll still be a perfromance drop over Non-ECC...or will the system totally ignore the extra few bits and run at full Non-ECC performance?

Thanks in advance!

- Omar

 

[sep]

Try running a utility that checks memory (CPUz, 3dMarks2001, etc.) and see if the memory reads ECC or NON.

Don't know if it will read from CMOS or attempt to analyse the mem itself. Worth a try.

 

[mbf]

The ECC feature on *any* motherboard that supports ECC (many boards don't, even if they use chipsets that do) will *ONLY* be enabled if *ALL* memory modules are ECC modules.

If there is even one (or two on dual channel systems) module, which hasn't the extra parity chip (that's more or less what distinguishes ECC from non-ECC memory) ECC cannot be enabled. That's because the feature can only be enabled or disabled, not enabled for a particular memory space.

However, if I were you, I'd remove the non-ECC modules and run with the ECC feature enabled (you may have to do that in the BIOS, even if you only use ECC modules). Sure, you lose a couple of percent on speed, but instead you could rest pretty much assured, that if you're machine crashes it isn't because of bad RAM or on the other hand be warned if there is bad memory in your system before damage occurs. The good thing about ECC is that if there are 1 bit errors for each 64 bit of memory, ECC will autocorrect the error (and tell you about it), giving you time to replace the faulty module.

I'd never again build a system *without* ECC memory, unless forced to. It just gives you that much more peace of mind!