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PC100 Server Memory

Chuck(G)

Chuck(G)

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I'm looking for some practical explanation of the difference between server memory labeled PC100-222-620R and PC100-222-622R. On my board 620R works fine, but 622R doesn't. Looking at data sheets, I don't see the difference. The motherboard manual is silent on the subject; it only mentions that the board takes PC100 ECC registered 3.3v SDRAM.

Can anyone enlighten me?
 
I think those last 3 numbers have to do with chip density and rank.
Rank is how many sets of chips are connected to the same adresses and data buses (controllers access one rank at a time, I think they have to be 64bit width per rank).

Can you read the specs of the individual chips?
 
The -620R (working) DIMM uses MT48LC16M4A2 chips (4Mx4)
The -622R (nonworking) DIMM uses MT48LC32M4A2 chips (8Mx4)

Both are dual-sided (9 chips per side) modules.

Not a lot of difference; I'd expect to see at least half the -622R DIMM, but nothing.
 
Chip density. Quite a few chipsets have a limit to what chip density they will read (either you see the whole DIMM or it will not work at all). What you are talking about is rank where the chipset only sees one bank instead of all the RAM on a stick.

One of the cool things I like about the VIA DDR1 chipsets is you can use cheap high density chips that will not work at all in intel boards (and most other OEMs).

What size DIMMs are they? What chipset are you using?
 
128MB and 256MB registered ECC DIMMs.

Chipset is Intel 440GX; supports 2GB and the board itself (Supermicro P6GDE) can do 133MHz FSB. I've got a couple of P3 1GHz SECC2s on the board and the board is stable at 133MHz.

I'd like to expand the memory to the full 2GB (using 4x512MB), but I need to be sure what's going to work and what's not.
 
Are you running the RAM at 133 or just the CPU? 440GX should only do 100 on the RAM side.

Personally I would just get 4 sticks of COMPAQ RAM from ebay 4 x 512MB PC100 server RAM since it is dirt cheap and see if it works. It shows up all the time.

Or you can just get this:

http://cgi.ebay.com/2GB-CORSAIR-MEMORY-RAM-KIT-L440GX-SDRAM-PC100-ECC-REG-/130423190190 which lists the 440GX in the description.


Server memory tends to be super cheap once the server is discontinued. The other day I got in 256MB x 4 Compaq server memory for $5.05 shipped (EDO ECC Buffered) as spare for my PR440FX dual PPro server.
 
Heh--622R SDRAM has a Compaq label on it (P/N 110958-032). So I'm a little skeptical about Compaq-labeled memory...

AFAIK, the memory's being run also at 133MHz FSB. But if you look at the datasheets for the individual chips, they're rated for 133MHz.

I was looking at this stuff.

Maybe it's worth the $10.
 
Its cheap enough, but many machines that specify PC100 have issues with PC133 (512MB sticks anyway, because of chip density). My main server is a Compaq (Proliant ML 330) and it has 4 x 512MB PC133 server sticks (Micron I think) I snagged from a recycler and it the machine is 100% reliable 24/7. Then again PC133 systems are not that picky.

Even if the chips themselves are rated at 133 maybe the board they are mounted on are not (they have rules on trace lengths for the different speeds). You would notice BSODs if that was the case.
 
Based on this message, it appears that the P6DGE doesn't like high-density SDRAM.

So, how does one tell the difference? I'm looking, for example at the Dataram 512MB PC133 DTM60194D. The organization is 64Mx72, which appears to be low-density. Am I on the right track?
 
32x8 is low density (16 chips), 64x4 is high density for 512MB DIMMs. 64Mx64 (or 64Mx72 for parity) just tells you you have a 512MB DIMM, not the configuration).
 
18 chip because of parity, would be 16 otherwise. Like I said you need to have low density chips. It is hard to know what the sellers have on ebay unless they mention density. DELL seems to use low density so that might help if the RAM came from a DELL.
 
Unknown_K said:
18 chip because of parity, would be 16 otherwise. Like I said you need to have low density chips. It is hard to know what the sellers have on ebay unless they mention density. DELL seems to use low density so that might help if the RAM came from a DELL.
Click to expand...

That's a good point--there are very very few memory sellers who mention density--not even the bigger ones like Crucial.

I've been using the memory certification documents that IBM still has online for its Netfinity servers. I attempt to pick one with the same chipset and a comparable CPU and go by that. Not perfect by any means, but at least it's something. Used to be that motherboard vendors would furnish compatible memory lists as part of documentation, but I guess they gave that up as memory part numbers and vendors change so frequently.

I picked up the Dataram. If it's a no-go, it's not a lot of money down the rathole.
 
Yea, sometimes you lose when you have to guess on what you need for some old system. For the most part at least the stuff is cheap enough. I know quite a few people who should know better buying high density (labled as such) on ebay DDR 1GB sticks and getting stuck with an item they can't use, and doing it in bulk.

Old servers are kind of fun to have these days, they are super cheap and use cheap RAM. My only issues is most do not have an AGP slot for video making them less usefull for a workstation. You can also pick up cheap PCI-X boards (except for video) for them as well.
 
There are also the "workstation" labeled boards that have provisions for decent video as well as multiple CPUs--and they use server RAM.

I'm debating on cooling for these CPUs--the (slot-1) originals came from an IBM server and have huge heatsinks. I don't really want to replace those and putting a small fan on each would be a tight squeeze (bad circulation), so I'm thinking about putting a large 100 mm fan on top of them. A trial with an old Papst gave a CPU temp of 35C after a couple hours of running, so that may be the answer.

It is kind of cool getting to use a motherboard that was made in the USA, however.
 
The Dataram PC133 512MB ECC registered DIMMs work perfectly. They show as 4 banks of 512M, even though they're 18-chip modules.

By comparison, if I populate the board with plain unregistered 256MB SDRAM to 1GB, it shows as 8 banks of 128M.

The POST screen stays up quite awhile, even in "quick boot" mode, but it otherwise works just fine.
 
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