rdram question

[Leland]

I need a quick answer.

I have an IBM netvista machine (model 6833) w/ 128 mb of RDRAM, which I need to use as a server (emergency). The RAM doesn't cut it so I need to upgrade it.

Please don't bitch about the machine, I hate it myself and would have loved to be working with anything else. Of course, I'm no systems guy, but also got thrown into that role (emergency).

Does RDRAM have to go in pairs?

ECC/Non-ECC? What do I buy? The ibm site doesn't help me much at all.

So, very quickly, I figure I need either 2-256 sticks or 2-512 sticks. What do I buy and where?

<EDIT>
This is what the IBM site tells me I have:
Four 184-pin gold-plated RIMM sockets (two per channel)
Supports PC600 or PC800 RIMMs (not PC700)
No support for ECC function (but ECC RIMMs will operate in non-parity mode)
Supports a maximum memory up to 1.5GB
Option part number for memory
NOTE: Mixing PC600 and PC800 RIMMs results in PC600 performance
</EDIT>

Can I get 4-256 sticks to get 1 gb of memory? What should I do, can I keep my 128 and a few 256 sticks?

Please help!

Thanks.

 

[Bellyofthebeast]

Yes, 16 bit rdram works in pairs. 32 bit rdram (which you don't have here) works as single modules, with appropriate mobo.

If your current rdram modules are pc600, don't use them. If your current rdram is pc800, but not Samsung, I'd still wouldn't use them, after this upgrade. Replace board with 2X512MB modules Samsung rdram 800-45ns or 800-40. I'd go with ECC, as that is not much costlier (than non ECC) & you have better quality memory for future purpose.

There is no question, the best rdram 800 out there is Samsung. In general, rdram performs better using 2 slots, as opposed to all 4. Of course, slots3#&4 would have crimms. Kingston rdram would be second choice. (Kingston uses Samsung chips on some of their rdram mem modules, but that is still not the same as original Samsung chips on Samsung mem boards, with dual heat spreaders.) I wouldn't consider any others, regardless of price. Don't go by the picture a vendor may use to show the mem offering, but make sure you have verified the Samsung part number/Samsung validation reference number, when ordering.

In my experience, the Samsung rdram 800-45 actually performs great (many have reported even better than the 800-40) & happens to be an excellent batch yield. (I just sold 4X512 modules Samsung rdram 800-45, when upgrading to a rdram 1066 mobo & now using rdram 1066-32 & I've used all kinds of rdram.)

PriceWatch can give you info on best prices/availability.

Mushkin is a solid vendor & will replace problem modules with no hassle, but prices are a little higher than others in general. I don't mind paying a little more for the peace of mind Mushkin provides. Googlegear & RunTime Computer are decent possible sources. Purchase mem from a vendor where you get a 15-30 day day return policy minimum, despite the fact Samsung mem is guaranteed by manufacturer. If a mem problem doesn't reveal itself within 15-30 days, then usually you're ok.

 

[Leland]

Mushkin is nice and cheap - $119 for a 256mb stick.

Will my machine take 4 of these or two?

Sorry to be so dumb, I haven't dealth with matching SIMMS in a while or ever with RDRAM.

 

[neilm]

I always thought kingston's PC1066 RDRAM was the best...

 

[Bellyofthebeast]

neilm,
We're talking about rdram 800 here, as Leland's mobo & bios can accept that.

Leland,
4X256MB modules would be ok. As stated before, there will be some bandwidth performance loss on most mobos, using all 4 slots with mem, as opposed to only 2. In your case though, a backup sytem, 4X256 sounds fine.

 

[Leland]

Thanks, I appreciate the help. In one fell swoop we lost two development machines and our systems guy. So, I got pressed into converting our print/share server into an emergency testbed. Not exactly a role I'm suited for, but what the hey, it gives me something to gripe about.

Performance is probably an issue at some point, but if the machine is too slow w/ 512, then I can just add another 512 to kick it up again, even if it's not as maximal as 2x512.