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YongHeun · Jun 17, 2001, 11:44 AM

Is there are anyones who know the difference between a high-profile ram and a low-profile ram? A Ti-Book needs a low-profile ram. A Pismo requires either a high-profile or a low-profile ram for upgrading the ram. Is there is any difference in its quality, speed, or somethingelse?

Paul S · Jun 17, 2001, 02:23 PM

It has to do with the size of the chip. Low profile chips are physically smaller, even though they are still SO DIMMS like others. Some machines don't have much room inside so they need the smaller chips, which sometimes are more expensive.

YongHeun · Jun 17, 2001, 10:36 PM

I heard that a high-profile ram chip produces more heat than a low-profile one, since a high-profile one is faster. Is it true or not?

imacaholic · Jun 17, 2001, 11:02 PM

Speed is not the issue. The physical size of the chip is. The Pismo PowerBook can use a "normal" profile or low profile chip in the upper slot, and should only use a low profile chip in the lower "factory" slot. The "normal" profile or low profile of the chip becomes most important with the larger (512MB) chips. Again, the main difference is the dimension of the chip.

YongHeun · Jun 18, 2001, 01:12 AM

'Pismo [---] should only use a low profile chip in the lower "factory" slot.'

Really thank you for sharing your information on the ram with me!!!

I have two questions. The first one is about how to install the ram chips. I ordered two 256 MB chips to upgrade my pismo. One of them is a high-profile one, and the other is a low-profile one. Before I installed these chips, I asked a technician of an internet retailor store about which one should be installed into an upper or lower slot. His answer was that it would be OK either to install a high-profile chip into a lower slot or to install a low-profile one into an upper slot. Was it a wrong information?
The second one is about 222S ram module. Two ram chips I bought are 222S ram modules. The original 128 ram provided by Apple was a 322S one. Is it OK to install these 222S chips into my pismo? Otherwise, do I have to install a 322S low-profile chip into the lower slot like the original Apple setting?

[ 06-18-2001: Message edited by: YongHeun ]

[ 06-18-2001: Message edited by: YongHeun ]

elzinat · Jun 18, 2001, 12:57 PM

222 and 322 are latency speeds of the RAM. 222 is faster than 322, but the difference is effectively none. In theory, if there is an 322 speed ram in your computer, all ram should run at 322 (including the modules capable of running at 222). The latest firmware from Apple in fact requires all ram to run at 322, since Apple decided that the slower ram was functionally more stable. When this firmware was released, there was an enormous controversy, because it disabled many ram chips in many people's computers. This was because, as it turns out, many manufacturers had been producing 222 ram which would not run at 322 (as the technical specifications for the ram instructed all such ships should), and the new apple firmware automatically disabled ram that would not run at 322. The point is 1)whether the ram you install can run at 222 doesn't matter. 2)if you ram you install can't run at 322, and you have the latest firmware, your ram will be disabled. so then you call the ram people and complain and they will send you ram that works. but this shouldn't be a problem.

YongHeun · Jun 18, 2001, 01:29 PM

Originally posted by elzinat:
<STRONG>222 and 322 are latency speeds of the RAM. 222 is faster than 322, but the difference is effectively none. In theory, if there is an 322 speed ram in your computer, all ram should run at 322 (including the modules capable of running at 222). The latest firmware from Apple in fact requires all ram to run at 322, since Apple decided that the slower ram was functionally more stable. When this firmware was released, there was an enormous controversy, because it disabled many ram chips in many people's computers. This was because, as it turns out, many manufacturers had been producing 222 ram which would not run at 322 (as the technical specifications for the ram instructed all such ships should), and the new apple firmware automatically disabled ram that would not run at 322. The point is 1)whether the ram you install can run at 222 doesn't matter. 2)if you ram you install can't run at 322, and you have the latest firmware, your ram will be disabled. so then you call the ram people and complain and they will send you ram that works. but this shouldn't be a problem.</STRONG>

I tested my two 222S ram chips by using DIMM First Aid softwares. The test resut said that "all your DIMMs checked out OK, it should be safe to update your firmware."
Despite this test result, will I have to replace a low-profile 222S chip with 322S one?

elzinat · Jun 19, 2001, 10:53 AM

that test result means that both of your 222 ram chips can properly run at 322 speed, so you will have no problems.
If you ran that test, then you have already installed the new ram, and it's working, right?
And if you don't yet have the latest firmware, you can install it without worrying about your ram getting disabled. I can't recommend the firmware upgrade simply because I don't know anything about what it does. You might want to check the PB forum on that one.