Please help: Why aren't these RAM memory modules working?

[Petros_k]

PC is an HP xw4600
http://h18000.www1.hp.com/products/quickspecs/12792_na/12792_na.PDF

System has 4 slots for RAM, should be able to take up to 16 GB as shown in diagrams in the above manual. I'm trying to remove the existing 1 GB RAM in 2 slots and install 2 GB modules in each slot for a total of 8 GB.



The PC is used and works fine with 2 sticks of this RAM:

Samsung M378T2863EH5-CF7
label on module: 1 GB 1Rx8 6400U-666-12-22
240 pin, unbuffered
PC2 6400 DDR2 -800 (400MHz @ CL=6, tRCD=6, tRP=6)

Samsung specs:
http://www.samsung.com/global/business/semiconductor/file/product/ddr2_product_guide_feb_12-0.pdf



Link to the RAM I bought and trying to install:

http://www.ebay.com/itm/HYNIX-8GB-4X2GB-2Rx8-PC2-6400U-666-12-HYMP125U64CP8-S6-AB-C-/251443417038?_trksid=p2047675.l2557&ssPageName=STRK%3AMEWNX%3AIT&nma=true&si=0EpluMAPx668S0l7Ys3HWqYoNdg%253D&orig_cvip=true&rt=nc


Hynix PC2-6400U-666-12 HYMP125U64CP8-S6 AB-C
label on module: 2 GB 2Rx8 PC2-6400U-666-12

Hynix specs:
http://www.skhynix.com/inc/pdfDownl...products/gl/products/dram/down/DDR2MODULE.pdf


I get an error of 5 red lights when I try to start the computer with the Hynix RAM, and that's supposed to mean a memory module problem for the HP xw4600. What am I missing here? These aren't the same type of RAM?

 

[crashtech]

The difference is that your old RAM is single rank, and the stuff you bought is dual rank. You need to send that dual rank RAM back. Too bad you don't need FBDIMMS, because I have an xw8600 with 16GB just sitting around.

 

[Petros_k]

Please explain: Single Rank vs. Dual rank ?

{EDit: Found a good explanation here: http://www.oempcworld.com/support/SinglevsDualRAM.html ]

Additionally: Does this mean I can only go to 8 GB (4 x 2 GB modules) if each module is "Single Rank" (and how do I know when I try to find it)? Am I going to be able to do 4 x 2 GB with single rank modules?

 

[crashtech]

The critical difference is in bold:

1 GB 1Rx8 6400U-666-12-22

2 GB 2Rx8 PC2-6400U-666-12

It's the circuitry inside the RAM and either controllers are designed to work with it or they aren't. I ran up against this same problem a long time ago, but the vendor fortunately saved me from making a mistake.

 

[crashtech]

Oh, well the stuff you got doesn't look to be ECC? But neither are your old ones. You had a 5 instead of an S in the part number and that threw me. You might want to look at part # M378T5663EHS

 

[Blain]

Seller of the RAM you bought and are trying to install...

"ANY PROBLEMS, USE CONTACT SELLER. I WILL FIX WHAT EVER IS THE PROBLEM"

Have you contacted the seller about the problem?

 

[Petros_k]

Seller of the RAM you bought and are trying to install...

"ANY PROBLEMS, USE CONTACT SELLER. I WILL FIX WHAT EVER IS THE PROBLEM"

Have you contacted the seller about the problem?

Actually, I just checked my email and he's willing to take it back for a refund. Nice seller. But that's only half my problems...

I need to upgrade the RAM for this system and now I'm not sure what to look for. In fact, I can't understand why the HP manual for the xw4600 doesn't specifically state only "single channel" RAM modules are compatible. Why doesn't it state this if it's an obvious issue?

 

[Petros_k]

Oh, well the stuff you got doesn't look to be ECC? But neither are your old ones. You had a 5 instead of an S in the part number and that threw me. You might want to look at part # M378T5663EHS

Both the Samsung RAM that is working okay and the Hynix RAM are non-ECC (there's an even number of individual chips, which I know I read somewhere indicates the non-error correcting type).

I'm still wondering though how do you actually know the HP xw4600 can't use dual channel RAM (other then the obvious that it's not running when I install it) ? I can't seem to find info on this anywhere as it pertains specifically to the HP workstation PC.

 

[Petros_k]

Pg. 11 of the xw4600 manual (link is above):

Memory Modes: Dual channel

Memory Configuration supported:

"PC2-5300E DDR2-667 ECC Unbuffered or PC2-6400E DDR2-800 ECC Unbuffered RAM DIMMs
Only Error Checking and Correcting unbuffered DDR2 DIMMs are supported and must be either x8 or x16
width [*Note this is questionable because existing RAM is non-ECC]. Memory upgrades are accomplished by adding DIMMs of the same or varied sizes. The Intel chipset supports both PC2-5300 DDR2-667 and the PC2-6400E DDR2-800 ECC unbuffered memory. It is suggested to not mix ECC and non-ECC memory.
For best performance the total amount and type of memory loaded into Channel A and Channel B should be
the same. If it is not, your computer will see all the RAM installed but will run the memory controller at a
lower performance mode. Although not required, for best performance add the memory in pairs rather than
as a single DIMM (two 1 GB DIMMs will have better performance than a single 2 GB DIMM). Also, add the
memory into both channels (e.g., one in socket 1 and one in socket 3) to take advantage of dual channel
performance. If you have unused slots within a channel, make them socket 2 and socket 4. This provides the
best margin for the memory bus. If you are only using 1 DIMM, install it in socket 1."


But on pg. 12 when you look at the first column for possible RAM configurations it says "single channel performance configuration," but it's unclear if they mean for only a 512 MB module.

And based on what they say in the paragraph above, "dual channel" means the two adjacent slots on the motherboard (not the RAM module itself being "dual channel."

This is very confusing...

 

[Petros_k]

Even more confusing:

Here's an Ebay merchant selling RAM specifically for an HP xw4600:

http://www.ebay.com/itm/8GB-4X2GB-M...6944987?pt=US_Memory_RAM_&hash=item35ba2f8c5b

The modules clearly say 2Rx8, and they claim it's certified to work with an HP xw4600.

And here's another one:

http://www.ebay.com/itm/4GB-Third-P...8559260?pt=US_Memory_RAM_&hash=item232bcab11c

 

[Petros_k]

http://www.tomshardware.com/forum/324953-30-memory-ranks-xw6200-workstation

Someone is giving advice about upgrading RAM on a HP xw6200 (later model workstation) and he says:

"You can run 4, 2gb single ranked ddr2 ECC registerd dimms. The HP documentation does not spell this out clearly.

I just bought a sizable lot of ram for my 3 xw6200s on ebay. All was ECC registered memory. The chips with 2rx4 on the sticker don't work. 1rx4 chips work fine. I think it is safe to assume that the 1 and 2 are for single and dual rank and that your PC needs single ranked dimms. "


Someone else says:

"Your system supports both Single and Dual Ranked memory modules. But the HP does say that whether all the slots support the Dual rank memory. But when mixing single and Dual rank the the last two slots use the dual rank memory (Slot 3 & 4). I think all the slots will run with dual rank maybe a BIOS update should enable this. If you are intending to play it safe then stick with the single rank memory.

Note acc to the manual: In DDR2 mode, dual-rank DIMMs are placed farther from the Memory Controller Hub (MCH) than single-rank DIMMs."

Could this get more confusing?

 

[Petros_k]

HP xw4600 manual from 2007:
http://www.nts.nl/site/html/modules/pdf/Workstation/HP_Workstation_XW4600.pdf

"Only Error Checking and Correcting unbuffered DDR2 DIMMs are supported and must be either x8 or x16 width. Memory upgrades are accomplished by adding DIMMs of the same or varied sizes. The Intel chipset supports both PC2-5300 DDR2-667 and the PC2-6400E DDR2-800 ECC unbuffered memory. It is suggested to not mix ECC and non-ECC memory.

For best performance the total amount and type of memory loaded into Channel A and Channel B should be the same. If it is not,your computer will see all the RAM installed but will run the memory controller at a lower performance mode. Although not required, for best performance add the memory in pairs rather than as a single DIMM (two 512 MB DIMMs will have better performance than a single 1 GB DIMM). Also, add the memory into both channels (e.g. one in socket 1 and one in socket 3) to take advantage of dual channel performance. If you have unused slots within a channel, make them socket 2 and socket 4. This provides the best margin for the memory bus. If you are only using 1 DIMM, install it in socket 1.

MAXIMUM MEMORY
Supports up to 8 GB DDR2-667 or DDR2-800 ECC unbuffered memory"



HP xw4600 manual from 2010:
http://h18000.www1.hp.com/products/quickspecs/12792_na/12792_na.PDF

"Maximum Memory:
Supports up to 16 GB DDR2-667 or DDR2-800 ECC unbuffered memory

Memory Configuration
(Supported)
PC2-5300E DDR2-667 ECC Unbuffered or PC2-6400E DDR2-800 ECC Unbuffered RAM DIMMs
Only Error Checking and Correcting unbuffered DDR2 DIMMs are supported and must be either x8 or x16
width. Memory upgrades are accomplished by adding DIMMs of the same or varied sizes. The Intel chipset
supports both PC2-5300 DDR2-667 and the PC2-6400E DDR2-800 ECC unbuffered memory. It is suggested
to not mix ECC and non-ECC memory.
For best performance the total amount and type of memory loaded into Channel A and Channel B should be
the same. If it is not, your computer will see all the RAM installed but will run the memory controller at a
lower performance mode. Although not required, for best performance add the memory in pairs rather than
as a single DIMM (two 1 GB DIMMs will have better performance than a single 2 GB DIMM). Also, add the
memory into both channels (e.g., one in socket 1 and one in socket 3) to take advantage of dual channel
performance. If you have unused slots within a channel, make them socket 2 and socket 4. This provides the
best margin for the memory bus. If you are only using 1 DIMM, install it in socket 1."



So the questions are (other than the single rank vs. dual rank issue):

1. Could the problem be that the memory MUST be ECC? - Answer should be no, because it runs with 2GB non-ECC.

2. But -- Can it be that it supports up to 2 GB non-ECC and up to 16 GB ONLY if RAM modules are ECC ?

3. Plus, how do you explain the 2007 manual says the system supports up to 8 GB RAM but the 2010 manual says suppots up to 16 GB RAM?

4. (Still ongoing) Why doesn't either HP manual for the xw4600 state the memory modules must be single rank?

 

[crashtech]

The truth is that it's too old to worry this much about.

I'm gonna be parting out my xw8600 soon, it's much better than what you have, and yet even with dual CPUs, a modern i5 will kick its ass.

If you are dead set on using your old machine, the only absolutely foolproof method is to use the HP part# recommended for your machine:

http://h20565.www2.hp.com/portal/si...x.portlet.endCacheTok=com.vignette.cachetoken

 

[Petros_k]

The truth is that it's too old to worry this much about.

Point taken, but this is actually a used system I just purchased for $100, and it's in great condition. It needs more RAM. I don't need an i5 or even an i3 CPU (I'm not a gamer). This PC has a Core2 Duo E8400 3.0GHz CPU, and that's plenty for me. I am also a fan of recycling used systems, even though I'm not very savvy at troubleshooting and it can be a pain to find the right parts for upgrading.

Thanks for that HP link. If you notice on the chart you provided, all of the replacement parts are ECC memory. I don't know if this is further evidence that if you want to go higher than 2 GB RAM you need to use ECC modules. I am positive that the Samsung RAM modules in it now (specs are above) are non-ECC.

The point is I don't know for sure if the problem is a) using non-ECC memory modules that total 8 GB, or b) using dual rank modules. I am still finding a mix of info on single rank (1Rx8) and dual rank (2Rx8) being recommended for the xw4600. I took a look at my BIOS and there's nothing there to set for ECC or non-ECC.

I'm wondering too if an HP tech support email might be the best way to get a definitive answer on this. To have to buy the single rank memory, if it's not the real problem, is an extra expense for no reason.

 

[coffeejunkee]

Only Error Checking and Correcting unbuffered DDR2 DIMMs are supported and must be either x8 or x16
width [*Note this is questionable because existing RAM is non-ECC].

The manual is not exactly the pinnacle of clarity but I think they mean ECC unbuffered vs ECC buffered, because it also says: "It is suggested to not mix ECC and non-ECC memory." If it only supports ECC memory why would you mix at all?

But have you updated the bios like the guy in your post 11 suggested? Then again, his 'put it in slots 3&4' doesn't really make sense, single-rank ram should be able to run dual channel as well.

Anyway, seeing your single-rank ram works it's probably best to stick to that. Would be nice if they mentioned it in the manual though.

 

[Petros_k]

Actually, I had more time to systematically test the Hynix RAM today, and I got a couple of surprises.

The dual rank, non-ECC Hynix RAM sticks work in the HP xw4600. My tests:

1. First test is to check all RAM modules are working. This means each one is installed individually, and it has to be in slot 1 of the motherboard.

Results: One of the RAM sticks is definitely defective. I was surprised to see the 5 light error occur only when the system booted with the defective module installed. Note that this means the motherboard is compatible with "dual rank" modules.

2. Second test was to see if another RAM stick works in slot 3 when a working module is installed in slot 1. This is "dual channel" mode.

Results: This configuration works fine. I got a BIOS message at start up telling me that RAM was being updated to 4 GB.

3. The last test I wanted to do was install RAM to make sure all the slots on the motherboard work together. I could have simply put the existing Samsung 1 GB sticks into slots 2 and 4, but recall these are 1Rx8 single rank modules. I see from the Internet that it's possible to mix single and dual rank in some cases, but I have no clue what is actually recommended for the motherboard in the xw4600.


Now I need to decide whether to send it all back to the original Ebay seller (he had emailed me when I told him I had a problem and he said he would take it back for a full refund) or keep at least 3 sticks and find one more that has the same specs as the Hynix so that I get 8 GB total. I thought I got a good buy at $57 for 4 x 2 GB.

Oh well...

 

[AlexAL]

Send back just the one stick?

 

[Petros_k]

Send back just the one stick?

..and just look for a single 2 GB RAM stick on Ebay with the same specs as the other Hynix sticks.

I also ran Memtest86 today for the three working modules and got back 0 errors with two passes of the test. So I'd say it's safe to assume the three working sticks will be reliable. The fourth defective one goes back to the seller (if he wants it) but I should be getting a partial refund.

 

[dave_the_nerd]

If you are dead set on using your old machine, the only absolutely foolproof method...

Or the Crucial Memory Finder tool.

Core 2 Duo/Quads were picky about RAM DIMM density and stuff.

 

[crashtech]

OP, I feel like I should apologize for not suggesting a more comprehensive testing method. My prior experience with the xw line led me to jump to conclusions, and that was wrong. Sorry.

I'm glad you had enough sense to test them one at a time.

 

[Petros_k]

OP, I feel like I should apologize for not suggesting a more comprehensive testing method. My prior experience with the xw line led me to jump to conclusions, and that was wrong. Sorry.

I'm glad you had enough sense to test them one at a time.

That's okay! You taught me something about RAM sticks that I didn't know (single rank vs. dual rank).