Registered ECC or Non-registered ECC 1

[Uziel]

A customer of mine wishes to upgrade his server (hp proliant). At the moment its running registered ECC DDR.
He tried standard DDR (obviously wont work), but is it possible to run non-registered ECC alongside it?
Due to the HUGE price difference (£80 as opposed to £210)
I've heard it said that it should be possible, but i want a bit more re-assuring.

Smoe reply quickyl please!!!
Thanks


John

 

[cdogg]

It depends on the CPU and whether you would want to. Most, if not all, motherboards support the mixture of ECC and non-ECC. However, realize that as soon as you mix them, the parity of ECC is lost as the system is forced to run in Non-ECC mode for all installed memory modules.

I also mention the CPU, because the newer Xeons for example require registered RAM.

~cdogg
"Insanity: doing the same thing over and over again and expecting different results." - Albert Einstein
[tab][navy]For general rules and guidelines to get better answers, click here:[/navy] faq219-2884

 

[rvnguy]

Uziel,

Bottom line, ECC Registered is required by and as cdogg implied; "would you want to", most/all server architectures.

Servers almost/always demand ECC/Registered memory. In a 24/7 environment and mission critical service a slip that is not detected can propogate into garbage data. Registered Mem has additional chips that are the registers (cache-like) for data moving off the memory to the next location and this requires a clock cycle. Without getting too detailed, As the memory store increases, this actually provides for faster data movement.

If this is a single processor Proliant
You can populate in matched(size/type) pairs but it is recommended for optimal performance that memory amounts be matched.

If this is a multi processor Proliant
Memory must be installed in pairs, and all mem on a processor board must be sized matched. Other processor boards can have a different size mem panels but must also be matched to each other.

I do not know the rules for International shipment/import but look at this link and apply the proper tariffs:

OCZ 1GB ECC Reg mem

http://store.yahoo.com/directron/ocz4001024sser.html

Hope this helps clarify

rvnguy



"I know everything..I just can't remember it all

 

[Freestone]

The server specifications dictate the type of ECC memory to use and whether registered and non-registered ECC memory can be mixed. Offhand I would say the two cannot be mixed since registered memory takes one extra cycle to fill the buffers (registers), and its data availablity would lag non-registered memory.

Consulting the server's manual would be your best bet.

 

[cdogg]

Freestone,
I was saying that pretty much all motherboards support the mixture, but when you do that, it forces the ECC memory to run in Non-ECC mode. That's all.

I wasn't saying that you could mix them and have one DIMM run in ECC mode, and another DIMM running in Non-ECC mode. That's just not possible.

~cdogg
"Insanity: doing the same thing over and over again and expecting different results." - Albert Einstein
[tab][navy]For general rules and guidelines to get better answers, click here:[/navy] faq219-2884

 

[Freestone]

cdogg,

My response wasn't directed at you at all, and I'm sorry it was interpreted as such. I was answering Uziel's question regarding mixing registered and non-registered ECC memory in the server.

I will point out, though, that non-registered does not necessarily mean non-ECC, which I think is how you interpreted Uziel's query.

 

[cdogg]

Oh yes, completely overlooked that. Thanks![tab]


OK, let's take a step back. There are 3 basic types of memory you can buy:

1) Non-ECC
2) ECC, unregistered
3) ECC, registered

Point 1. ECC (unregistered) can be mixed with Non-ECC

Point 2. ECC (unregistered) cannot be mixed with ECC (registered)

The reason? It won't physically fit! Registered DIMMs are usually keyed differently. See:

http://www.centon.com/faqmemory.htm#q43

~cdogg
"Insanity: doing the same thing over and over again and expecting different results." - Albert Einstein
[tab][navy]For general rules and guidelines to get better answers, click here:[/navy] faq219-2884