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LC630 DOS Compatible supports 64MB SIMMs - 84MB total!

Brett B.

Well-known member
I got two of these 64MB 72 pin SIMMs quite a while back and finally got around to using them.  One went into my LC475 where it worked great, and not unexpectedly.  The other was destined for my LC630 DOS Compatible machine which allegedly has a ceiling of 52MB - 32 in one slot, 16 in the other, and 4MB onboard.  I know for a fact that the 16MB card is the absolute max for the first slot (tried a 32MB stick in it, no luck) but the second was unknown.

Now we know!  Can't promise YOUR Q/LC630 will support these, but mine does.  SUPER excited about this.

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360alaska

Well-known member
Yeah, the Mac side will support a 64mb ram stick, but the PC side not so much. The 630dos board is the same board that comes in a lc 580, with the main difference being that it has an extra ram slot when compared to a regular 630.

 

AlpineRaven

Well-known member
I think the DOS side was funny with large amount of memory - I think I recall it'll do between 16mb and 32mb but no more.

Cheers

AP

 

Brett B.

Well-known member
Just for fun I ordered a 128MB SIMM.  We'll see if that works, 148MB memory would be dope.

I will have to try the 64MB stick on the DOS card.  I'd be shocked if it works.  I was surprised that it worked on the Mac side.

I also tried two Kingston 64MB SIMMs in my 6200/5260/120 machine and only 64MB was recognized there.  Odd.

 

Brett B.

Well-known member
Well, it appears that it also supports 128MB modules!  Sweet!

I also have confirmation that the DOS card definitely does NOT support my 64MB stick.  It showed up as a 16MB module.  32MB works fine.  Kinda weird but whatever.

KIMG1390.jpg

 

johnklos

Well-known member
Actually, all of these motherboards which have two SIMM slots support one single bank SIMM and one dual bank SIMM, so you can have a 64 meg SIMM and a 128 meg SIMM, plus the four on the motherboard for a total of 196 megs.

 

Brett B.

Well-known member
Hmm, now to find a 64MB single bank SIMM.  I know the 32MB and 64MB ones I have now will not work in the single bank slot.  

FWIW this 128MB stick I got was from "memorymasters" on eBay and is FPM, non-parity, 60ns

 

Trash80toHP_Mini

NIGHT STALKER
If you have a RAM check utility, try it and see if it shows memory segmented into 4 Banks?

4MB on the floor should be Bank A

16MB Single Bank slot would then be Bank B

128MB Dual Bank slot would then be Banks C and D

If anyone knows of a RAM test utility that does show memory as grouped in banks, please let us know. Long time curiosity has been whether disabling Bank A and patch wiring CAS and RAS lines from it to the Single Bank socket might have its support level upgraded to equal to the more capable slot. :huh:

edit: don't have a DOS board and my first release Quadra 630 lacks both the second slot and the video connector required for DOS Compatibility. If/when I find my Q630 board I'll be trying this with a 72-pin to 72-pin SIMM Saver.

 
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Trash80toHP_Mini

NIGHT STALKER
Damn betcha. But as always, early adopters are the ones on the ground with the arrows sticking out the front side and the bullet holes in the flip side. :-/

 

johnklos

Well-known member
Hmm, now to find a 64MB single bank SIMM.  I know the 32MB and 64MB ones I have now will not work in the single bank slot.
When I found a bunch of 128 meg SIMMs on eBay for $8 apiece, I bought a bunch because they'll definitely work as 128 megs in dual bank slots and as 64 megs in single bank slots. Sometimes it's better than trying to find the right kind of 64 meg SIMM.

 

Paralel

Well-known member
When I found a bunch of 128 meg SIMMs on eBay for $8 apiece, I bought a bunch because they'll definitely work as 128 megs in dual bank slots and as 64 megs in single bank slots. Sometimes it's better than trying to find the right kind of 64 meg SIMM.
That makes sense, with the right 128 MB SIMM, if the machine can only read one bank in the slot it's in, it will appear as a 64 MB SIMM.

 

Brett B.

Well-known member
What's the technical reason for limiting one slot to single bank only and not the other? 

I looked around a little and it appears that the 64mb modules are going to be hard to find. Maybe I'll order up a couple more 128mb ones sometime. I'm tempted to try one in the LC475 now, I bet it works. I'm still surprised that the 6200/5260 maxed out at 64mb though 

 

johnklos

Well-known member
The LC475 can take 64 and 128 meg SIMMs just fine.

I think the idea is that the IDE Quadras only have four banks of memory total, so one bank is the 4 megs on the motherboard, the other is the single bank SIMM socket, and the other two are the dual bank SIMM socket.

 

Paralel

Well-known member
The LC475 can take 64 and 128 meg SIMMs just fine.

I think the idea is that the IDE Quadras only have four banks of memory total, so one bank is the 4 megs on the motherboard, the other is the single bank SIMM socket, and the other two are the dual bank SIMM socket.
Bingo

 

Brett B.

Well-known member
Oh I see.  That makes total sense and I glossed over that in Trash's post above.  My bad!  :scrambled:

 
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