VRAM DIMM

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VRAM DIMM

I have a Power Macintosh 7200/90 that I got on EBay I am upgrading the Ram on it, I opened up the case last night to see what was inside if there were any empty slots. There are 4 stick 2 look like normal ram but the other 2 I discovered this morning as I was looking on eBay look like VRAM DIMM, they are very thick and look like a picture that I found on eBay of VRAM DIMM. Is it possible for these to be in the DRam slots instead of the VRam slots would the computer still work? Also is it possible for me to use memory from a Ruby IMac G3 DV? I have two 68 mb sticks that I took out of my IMac that I hate to waste.

Apple iMac DV G3/400 Ruby Red & Power PC Macintosh 7200/90 Mac OS X (10.0.x) 400 MHz PowerPC 750, 128 MB ram, 20 GB Hard Drive, Slot Loading CDROM

Posted on Mar 31, 2006 9:40 AM

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Answer 1

Allan Jones

Level 10

80,436 points

Mar 31, 2006 9:51 AM in response to wolflady

Hi wolflady,

This page has comprehensive info on RAM and VRAM for the 7200, along with a handy logic board diagram. The diagram shows where the RAM and VRAM reside on the board.

The VRAM is a special DIMM so you can't switch RAM for VRAM.

The RAM from your iMac will not work in the 7200. Although both are 168-pin DIMMS, there are electrical differences. The 7200 takes 5v RAM and the iMac DV takes 3.3V,. There are some other differences, too,

Allan

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Answer 2

wolflady Author

Level 1

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Mar 31, 2006 10:01 AM in response to Allan Jones

Hey Allan

I do understand that they can't be switched but what I am saying is someone put two sticks that look like VRAM in the RAM slots, and I wanted to know if the computer would still run if that is the case? When I get home tonight I am going to take a closer look but I'm almost sure they are VRAM. I'm sorry to hear that the Imac ram won't work in the 7200. Now I just have to figure out what to do with the old RAM.

Apple iMac DV G3/400 Ruby Red & Power PC Macintosh 7200/90 Mac OS X (10.2.x) 400 MHz PowerPC 750, 580 MB ram, 20 GB Hard Drive, Slot Loading CDROM

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Answer 3

Allan Jones

Level 10

80,436 points

Mar 31, 2006 10:16 AM in response to wolflady

I see.

Some older DIMMs are "fatter" than we see today. I can't say for sure if that makes them VRAM. The computer may run with VRAM in the RAM slots (assuming they have the same pin layout) but they would certainly not be recognized. It is more likely that the computer would not boot, giving the "breaking glass" sound instead of the normal startup chime.

When you get the computer open tonight, shine a light into the RAM and VRAM slots (reference the logic board diagram. Slots have bars every so often that "key" them for the right RAM. The RAM sticks have corresponding notches to clear the bars for full insertion. I doubt that RAM and VRAM for the same computer would have the same pattern of bars.

The RAM from the iMac will work in Beige G3s, Blue & White G3s, and early G4s--any Mac with a system bus speed of 100mHz or less, except the early eMacs. Even though they had a 100mHz bus, they have to have 133 speed RAM for some reason.. That iMac RAM is called "DRAM" and is a more evolved type than that used in older Macs.

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Answer 4

Jeff

Level 6

12,334 points

Mar 31, 2006 8:22 PM in response to wolflady

Some older DRAM memory has longer, horizontally-mounted chips on it (4 of them on one or both sides), instead of narrow, vertically-mounted chips. These DRAM DIMMs resemble the smaller VRAM cards, but they are much longer. The VRAM DIMMs couldn't mistakenly be substituted for DRAM in the memory slots. The memory DIMM is 5 1/4" in length, while the VRAM DIMM is only 3 7/8" long.

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