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View Full Version : Why Mac is so picky for rams?


msharp
Feb 18, 2005, 06:51 AM
What's the key factor for a ram to work stably with full capacity in a Mac(say, powerbook)?

is there something really special for "Apple" Ram Sticks?

for instance, two branded ram with the same specification(at least, they're the same at both of their website):
PC2700, Non-ECC, 333MHz, 128MB x 64bit, Unbuffered SODIMM, 2.5V(+-0.2), CL2.5

so what is the KEY factor if there is one
or
what ram specification is Apple expecting?

broken_keyboard
Feb 18, 2005, 07:33 AM
There's nothing different about Mac and PC RAM.
Nothing. Zero. Nada. Zip.

keysersoze
Feb 18, 2005, 08:22 AM
There's nothing different about Mac and PC RAM.
Nothing. Zero. Nada. Zip.

G5's have a serious dislike of cheap RAM-- numerous posts on this in other threads... many kernel panics. I had hynix RAM that caused my computer to crash repeatedly... replaced it with Crucial and it's fine now. I'd love to pay less, but I want stability. As for our G4 here at work, we've stuck all kinds of PC2700 in it and it chugs right along.

MisterMe
Feb 18, 2005, 08:23 AM
What's the key factor for a ram to work stably with full capacity in a Mac(say, powerbook)?

is there something really special for "Apple" Ram Sticks?

for instance, two branded ram with the same specification(at least, they're the same at both of their website):
PC2700, Non-ECC, 333MHz, 128MB x 64bit, Unbuffered SODIMM, 2.5V(+-0.2), CL2.5

so what is the KEY factor if there is one
or
what ram specification is Apple expecting?Macs tend to be assembled of industry-standard, albeit high-quality parts. It is the same with RAM. Compared to Wintel computers, Macs are less tolerant of out-of-spec RAM.

Sun Baked
Feb 18, 2005, 08:32 AM
so what is the KEY factor if there is one
or
what ram specification is Apple expecting?The SPD feature (which contains the dimms attributes) must be programmed correctly.

And a new twist says that the CKE signal must use a separate signal for each bank on the dimm, they cannot be tied together.

broken_keyboard
Feb 18, 2005, 08:43 AM
G5's have a serious dislike of cheap RAM-- numerous posts on this in other threads... many kernel panics. I had hynix RAM that caused my computer to crash repeatedly... replaced it with Crucial and it's fine now. I'd love to pay less, but I want stability. As for our G4 here at work, we've stuck all kinds of PC2700 in it and it chugs right along.

I have a G5 with 8 sticks of 256M el-cheapo RAM. Works just fine. I also used cheapo RAM on my Power Mac G4 and iMac G4. I have never understood people who say Macs are so fussy. (But that's just my personal experience, I am not denying your experience)

RacerX
Feb 18, 2005, 08:48 AM
G5's have a serious dislike of cheap RAM--
Actually pretty much all Macs have a built-in dislike of cheap RAM. This started with a firmware update in early 2001 and has been part of all new Mac since then.

Basically, Apple got sick of getting blamed for unstable systems where the real problem was cheap RAM, so they built-in a quality check to keep systems from running the stuff. From Apple's point of view it was better to make it harder for people to find RAM than to be (wrongly) labeled as having crash prone systems.

Back in 2001 a lot of people were surprised to find that not all their RAM was working after they had updated the firmware on their systems. The few times I came across this with clients, the original venders were willing to exchange the RAM for RAM known to work with Apple systems.

It is a good idea to buy RAM for a Mac rather than just buy RAM with the same specification. Sure, there will be a price difference, but you'll know that it'll work.

AlmostThere
Feb 18, 2005, 09:26 AM
Isn't this the issue that crucial (and others?) can charge more for different "modules" of RAM?

At www.crucial.com/uk

look up Apple -> PowerBook -> G4 1.67 15" and a 1Gb module costs 301

Details : DDR PC2700 CL=2.5 UNBUFFERED NON-ECC DDR333 2.5V 128Meg x 64

look up DDR 2700 -> 200-pin SODIMM and the 1Gb module is 214

Details : DDR PC2700 CL=2.5 UNBUFFERED NON-ECC DDR333 2.5V 128Meg x 64


So, what's the difference?

Gizmotoy
Feb 18, 2005, 09:54 AM
Isn't this the issue that crucial (and others?) can charge more for different "modules" of RAM?

At www.crucial.com/uk

look up Apple -> PowerBook -> G4 1.67 15" and a 1Gb module costs 301

Details : DDR PC2700 CL=2.5 UNBUFFERED NON-ECC DDR333 2.5V 128Meg x 64

look up DDR 2700 -> 200-pin SODIMM and the 1Gb module is 214

Details : DDR PC2700 CL=2.5 UNBUFFERED NON-ECC DDR333 2.5V 128Meg x 64


So, what's the difference?

Yes, Crucial does that crap all the time. In most cases, if you call them they will tell you they're the exact same chip, even though they carry different part numbers. Although, I'm sure on occasion they are actually different. Their support number is extremely helpful. I've got the cheaper non-Apple-marked Crucial chip in my 12" PB right now.

ibilly
Feb 18, 2005, 08:04 PM
Get crucial everybody. Great prices, great quality, great warranty. No, I dno't work for them, but my experience has been extremely positive.