LC III questions!

#1 Mon, 10 Aug 2009 - 06:20 68kMLA

I figure i'll get better results if i post here.

According to Mactracker, the LC III had 1 ram slot. If this is the case, what is the other slot that looks like a ram slot?

EDIT: I just remembered, we have a Wiki! Never mind, thats the vram slot.

What benifits would I get if i upgraded its vram?

Also, what kind of ram/vram chips would i need to upgrade it?

#2 Mon, 10 Aug 2009 - 06:43 68kMLA

The LCIII has 512KB of VRAM standard, soldered onto the motherboard, which cannot be removed, which gives you either:

Up to 16 bit (Thousands) of colours on a 12" monitor at 512x384

Up to 8 bit (256) colour on a 13 or 14" monitor at 640x480

and according to Apple, up to 4 bit (16 colours) on a 16/17" monitor at 832x624 (I've never run my LCIII at any res greater than 640x480, but I recall Apple saying that without a VRAM upgrade, the LCIII only supported 16 colours on those displays, despite 512KB normally being enough to run a display at that resolution at 256 colours on other systems)

You can put a 256 KB VRAM SIMM into that VRAM slot, expanding the total amount of VRAM to 768KB, which will give you:

Up to 24 bit (Millions) colour on a 12" monitor at 512x384

Up to 16 bit (Thousands) colour on a 13 or 14" monitor at 640x480

Up to 8 bit (256 colours) on a 16/17" monitor at 832x624

The LCIII takes the same kind of Apple VRAM SIMM as other 68k Macs, they're fairly easy to find if you know where to look, and the 256KB ones are fairly ubiquitous, since they were OEM in LCs, LCIIs and LC475s. If you want to upgrade the RAM, you'll need a 72 pin SIMM, preferably either 16 or 32MB.

#3 Mon, 10 Aug 2009 - 06:44 68kMLA

what kind of ram/vram?

IE: 72 pin 45v blah blah blah SIMMM

#4 Mon, 10 Aug 2009 - 16:35 68kMLA

The LC III shouldn't be picky on the type of RAM, as long as it's a 72-pin SIMM and isn't ECC.

However, I believe that the only type of VRAM you can use is one that is marked "LC ONLY" with a label on the back or otherwise one from any LC model.

#5 Mon, 10 Aug 2009 - 18:02 68kMLA

OK... if i want to add an FPU, what should I search for on eBay?

#6 Mon, 10 Aug 2009 - 21:15 68kMLA

OK... if i want to add an FPU, what should I search for on eBay?

68882

#7 Mon, 10 Aug 2009 - 21:23 68kMLA

so something like http://cgi.ebay.com/Motorola-MC68882-68882-co-processor-FPU-cpu-MC68882FN16_W0QQitemZ220347416031QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item334dbabddf&_trksid=p3286.m20.l1116

#8 Mon, 10 Aug 2009 - 21:47 68kMLA

No it needs to match the CPU's clock speed, so it should be a 25 not 16 like that one is. Also don't expect a big performance boost from it.

#9 Mon, 10 Aug 2009 - 22:08 68kMLA

The main processor(s) and MC68882 may operate at differant clock speeds.

Ha!

#10 Mon, 10 Aug 2009 - 22:33 68kMLA

The main processor(s) and MC68882 may operate at differant clock speeds.

Click to expand...

Ha!

So do you reckon Apple provided a different clock source for the empty FPU socket? Or might it share the same one as the CPU? I'll let you guess.

#11 Tue, 11 Aug 2009 - 06:49 68kMLA

The main processor(s) and MC68882 may operate at differant clock speeds.

Click to expand...

Ha!

Click to expand...

So do you reckon Apple provided a different clock source for the empty FPU socket? Or might it share the same one as the CPU? I'll let you guess.

:lol:

#12 Fri, 14 Aug 2009 - 20:56 68kMLA

iirc, apple's '00 memory guide says that you can put a 512k vram stick in an LC III and get 1MB of vram. is this true?

#13 Sat, 15 Aug 2009 - 02:58 68kMLA

IIRC the LCIII tops out at 768k...you can put a 512k stick in, but from memory it will still only be recognised as a 256k stick.

#14 Sat, 15 Aug 2009 - 03:18 68kMLA

ok.