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View Full Version : Is it practically possible to convert ecc registered RAM to "only" ECC RAM?

celemine1Gig
09-12-2006, 09:35 AM
Hi guys,

I had the idea yesterday when I found some nice Micron D9 fatbody RAM and realized that it was ECC registered, i.e. not compatible with my i955x based board.

Now the question, I came up with, is:

Would it be possible to remove the REGISTER- and the PLL-chip from the PCB, flash different SPD information and use the RAM as normal or ECC (non-registered) RAM?

I know it's kinda crazy, but you can't find fatbody RAM very easily anymore and the registered sticks would be quite cheap, too.

If there's other differences, besides the extra PLL and REGISTER, it's a mission impossible. But I don't really know for sure and only had a look at the dataheet yet.

BTW, here's the datasheet:

http://download.micron.com/pdf/datasheets/modules/ddr2/HTF18C64_128_256x72G.pdf

Any input i appreciated. I hope this idea isn't totally insane and I didn't make me seem like a complete fool. :D

Greetings from Bavaria!

Ingmar :slap:
uOpt
09-12-2006, 11:32 AM
It's probably more straightforward to get unregistered PCB boards and solder the chips onto the new board.

I don't think you'd have to worry about the SPD much as it will be high timings anyway.
celemine1Gig
09-12-2006, 02:22 PM
Hmm, so you think that it would be easier to transplant every single memory chip onto another PCB, than just desolder the two chips, which make the registered RAM act differently than "normal" non-ECC non-registered RAM?
To be honest, to me this sounds strange and I wouldn't do that for sure.

Any other suggestions?
Roger_D25
09-12-2006, 07:05 PM
How important is this RAM to you? I would say just go for it, see if it works? Like you I don't really know exaclty what would have to happen and I wasn't able to view the datasheet unfortuenlty. I definelty wouldn't go transplanting the ICs' onto a non-registered PCB though, way too much work I think. Then again that may be the only way it's possible! Please keep us posted on progress as I'm very intrigued by this now, hope it can be done! Great sticky material if it does, lol!
uOpt
09-13-2006, 07:53 AM
Hmm, so you think that it would be easier to transplant every single memory chip onto another PCB, than just desolder the two chips, which make the registered RAM act differently than "normal" non-ECC non-registered RAM?


The problem is you don't know what to do with the lanes after you rip off the chips.

Transplanting the chips to an existing module gives you all the wiring you need.

Otherwise you are stuck with learning what exactly the register chip is doing. I'd start by downloading the system integration manual for the register chip.
jackies
09-18-2006, 12:01 PM
Register chip is a buffer, it's there to reduce the load it places on memory bus, which is useful for servers and such, where you want to stick like a dozen modules in your mobo... Unsoldering it... no, I wouldn't try...
erwinz
09-18-2006, 08:16 PM
xtreme.. :D hehehe keep us posted.. :) get ready to be suprise at your result.. :d
celemine1Gig
09-19-2006, 01:31 AM
ATM, I just don't have the time, so this project can be regarded as history. :(
Demo
09-22-2006, 02:22 PM
If the ram doesnt mean much to you then by for the sake of extremeness and knowledge, remove those chips XD
celemine1Gig
09-23-2006, 02:34 AM
If the ram doesnt mean much to you then by for the sake of extremeness and knowledge, remove those chips XD

You didn't read this, did you?

ATM, I just don't have the time, so this project can be regarded as history. :(
don_vercetti
10-01-2006, 11:09 AM
Assuming this project ever goes forward, it would make sense to try and remove the 'registered' bits of the RAM first. Then, if this doesn't work, you can look at transplanting the IC's.

This is based obviously on the fact that if you remove the IC's and they don't work on a 'foreign' PCB, you're buggered. Wheras if you remove the 'registered' bits and they don't work, you can still use the IC's for something else.
uOpt
10-02-2006, 06:49 AM
Assuming this project ever goes forward, it would make sense to try and remove the 'registered' bits of the RAM first. Then, if this doesn't work, you can look at transplanting the IC's.

This is based obviously on the fact that if you remove the IC's and they don't work on a 'foreign' PCB, you're buggered. Wheras if you remove the 'registered' bits and they don't work, you can still use the IC's for something else.

Of course you can't just rip out the register chips. They connect the control lanes between the CPU and the RAM ICs, without the chips you cut the control lanes. That'll make for some hell of a latency because you have to use carrier pigeons or something.

The second plan is what I suggested earlier. The RAM ICs are the same for registered and unbuffered RAM.