dimm slots too tight?

[Zakalwe]

I have been rebuilding the OS on an old system that belongs to a relative. While I was at it, I decided to put in some extra RAM I had sitting around.
The motherboard is an unidentified model, I have no way of knowing what it is, as I can't see an fcc id, or any other markings. The board has 4x simm slots, and 2x dimm slots. I have added 2x16MB simms, and I also have a 64MB dimm, which I have slotted in there.

The question I have is this:
Has anyone else ever found dimm (or simm for that matter) slots to be ridiculously tight?
I had to push VERY hard to get the dimm into the slot. So hard in fact, that I was worried I might crack the motherboard, even though I had it well supported.

BTW, they are definitely the right type - I have the motherboard manual (which doesn't identify the make or model, but does list what all the slots etc. on the board are)

[causticVapor]

You inserted them at a 45deg angle from the side, right?
AS for the DIMMs, the side levers have to be fully open.
Check for ddebris as well.

And here's a tool to ID the mobo: http://www.motherboards.org/moboidtools.html

[Zakalwe]

Thanks caustic (or is that Mr Vapor? ), I will check that site out.

Yes, the simms were inserted from the correct angle, there was no problem with the simms, only the dimm. And yes, the levers on the dimm slot were fully open.

[wallie_x]

On older boards that have both simm and dimm slots, yes I found some to be VERY tight. Be careful not to flex the board too much while inserting the dimms. It is important to brace the board slightly so it does not flex too much as excessive flexing could break some of the traces and ruin the board. Do not touch the underside of the board with your fingers however. And to my knowledge, there is only a certain sequence that allows you to run both dimms and simms together. But memory is so cheap right now, I'd dump the simms and just run dimms.

[Peter M]

You should NEVER mix SDRAM DIMMs and SIMMs!

And yes, the DIMM slots on older boards sometimes are ridiculously tight. Putting something of appropriate thickness (like the board's manual ) underneath the board while inserting DIMMs keeps it from bending away.

[Zakalwe]

Hey, thanks guys.

So it seems like my experience is not that unusual.

Putting something of appropriate thickness (like the board's manual ) underneath the board while inserting DIMMs keeps it from bending away

- That's pretty much exactly what I did

You should NEVER mix SDRAM DIMMs and SIMMs!

- Why not?


And as regards dumping the simms, I agree, but this is not my system, and the owners don't have any money to spend on computers at the moment. Besides, they only use it for basic internet - ie checking their bank, and email, and some word-processing .

BTW, I did eventually get the dimm slotted in, and detected, although it only shows 124MB during post, with 4x16MB simms, and 1x64MB dimm I would expect to see 128MB. How can it lose 4MB off a 16 (or a 64)?

[Peter M]

Those 4 MB probably are going toward an integrated graphics unit. Another reason to ditch the SIMMs - those chipsets perform massively better when the VGA is running off SDRAM.

Why not mix? Signalling voltage of SIMMs is 5V, this will fry the 3.3V SDRAM's I/O buffers over time. Besides, timing between SDRAM and older memory is so wildly different that systems hardly ever are stable when you mix.

No money? Ah come on, PC100 64 MByte DIMMs go for below $10. I bet you'll find someone with an even older SIMMs-only system who'll happily pay you that for the SIMMs you have there.

[Zakalwe]

Thanks Peter,

I think you are exactly right about the grapics chipset accounting for that 4MB - I actually changed that setting in BIOS from 1MB to 4MB myself, but the penny didn't drop when I saw the 124MB... doh!

I can't see 64MB dimms for sale on the website for the local supplier, but 128MB dimms are about $55 here, so I am guessing the 64's are about $40 - usual thing with PC's, going up a step is always relatively less expensive, until you get to the bleeding edge components of course.

Still, I'm gonna think pretty seriously about springing for 128MB myself - it's for a family member.

So, with the signalling voltage being different, do you think I should ditch the older ram immediately, or risk destroying the dimm?
Has anyone else had any experiences - good or bad - with mixed memory?

[Peter M]

I've seen stock clearance deals on 64MB PC100 DIMMs for as low as $4.99.

Yes, pull the SIMMs immediately.

Beware, that old board (what is it anyway?) might not be able to run the larger DIMMs. Tell us what it is.

[causticVapor]

5v to me sounds like a pretty drastic overvolt. I need to destroy that CSS video stating you'll only lose performance, and not fry/lose stability when you mix them!

[Zakalwe]

Peter,

I will take your advice, and take out the simms. I'm at work right now, and can't tell you what the mobo is, but I'll check it out tonight and let you know.

As I said earlier, I do have the motherboard manual, listing sizes it can take, from memory 128MB dimms is the largest listed. Unfortunately it is one of those el cheapo type boards, and even the manual doesn't have a manufacturer name, or board model on it anywhere - which pisses me off no end by the way.

I guess RAM prices must be a little different in New Zealand, because I'm pretty sure you can't get 64MB for less than about $40 dollars. Still, hardly a king's ransom...