Old computer upgrade...

May 18, 2009 6:17 PM

Decrepit PC RAM question - I am trying to figure out what kind of SDRAM is supported by my K7VZA Rev 1.0 motherboard.

The manual states:
The mainboard accommodates PC 100/133 SDRAM (Synchronous DRAM) or VCM (Virtual Channel Memory) up to 1.5 GB using three 3.3V unbuffered DIMM modules. The mainboard attains the highest reliability by supporting ECC (Error Checking and Correction) memory protection, enabling the mainboard to achieve superior data integrity and fault tolerance with respect to memory errors while running applications.

-and later-

Install the Memory Modules
For this mainboard, you must use 168-pin 3.3V non-buffered Dual In-line Memory Modules (DIMMs). The memory chips must be standard or registered SDRAM (Synchronous Dynamic Random Access Memory).

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So that sounds like I can use ECC registered SDRAM DIMMS, right? For whatever reason, those are actually pretty cheap on eBay. But Crucial points me toward non-ecc, non-registered, which are not substantially more expensive but more than I want to spend on this dinosaur.

Is it possible the ECC is only for onboard cache and not installed RAM? There is some BIOS setting for RAM ECC on POST, so I actually think it does support it.

And if it doesn't really support registered RAM in all configurations, then the DIMMS won't work at all, right?

For bonus, what's the distinction between high and low-density for PC133 SDRAM? And will high density work? Crucial said something about max module being 256, but the sellers on eBay tend to just say low or high not Nx256 or anything...

posted by mzurer to computers & internet (5 comments total)

If your mobo manual says that your board supports up to 1.5GB RAM in up to three modules, then the maximum module size must be 512MB regardless of what Crucial says. Also, if your mobo manual says that your board can use registered and/or ECC modules, that's probably what it means. I'd just buy what you can on eBay and see if it works. If it doesn't, PC133 RAM (especially sticks bigger than 256MB) is an easy and potentially profitable re-sell.
posted by flabdablet at 6:45 PM on May 18

Dunno, but did you read this thread? They seem to think that PC100 or PC133 memory should work, but don't tackle the ECC issue. If you're adventuresome, just buy some memory and try it. The bigger question is, why are you putting money into this ancient dinosaur of a motherboard, whose reputation was none too good even when it was new? I think you'd be better off starting with a new motherboard, CPU, and memory. Unless, of course, you're trying to resurrect an ancient PC, in which case you really ought to think about replacing the power supply, before you blow up the motherboard, memory, and CPU.
posted by exphysicist345 at 6:51 PM on May 18

Well, it's right now what I believe to be the world's crappiest OpenSolaris installation, so I'm hesitant to even upgrade the RAM, just in case someone else is using something crummier but with more memory, lest I lose that distinction. This is for a project that is worth about $40 to me, and not much more. I actually already replaced the POS power supply a few years ago. I actually need to check the mishmash of DIMM's in there now - Maybe one of them will have some good info for me as they all work ok.
posted by mzurer at 6:58 PM on May 18

So that sounds like I can use ECC registered SDRAM DIMMS, right?

yes.

what's the distinction between high and low-density for PC133 SDRAM?

the number of chips on the dimm. nothing you really need to worry about.

I imagine the reason the non-ECC is on Crucial is that it may be all they're making anymore and Crucial just sells new stuff. Why ECC DIMMs are cheaper and on eBay could be that there is lots of old server RAM (ECC) that is just sitting around, waiting to be wanted.
posted by rhizome at 9:26 PM on May 18

Hey! I did just shell out the $30 and it works! Interestingly, the system seems to use about 30 megs more memory now than it used to, but it used to be pegged at 100% memory and now it's at 33% so it doesn't have horrid halting problems anymore.
posted by mzurer at 6:49 AM on May 22