[selowitch]

I got a lucky break in that Apple was willing to take back my CoreDuo iMac and gave me a Core2Duo because the former had shipped within 10 days of the announcement of the latter. Unfortunately, I just discovered that my new machine needs PC2-5400 instead of PC2-5300 memory, so now I have to send my memory modules back to Mushkin. Darn.

UPDATE: I called Mushkin and they say that there should be no difference between PC2-5400 and PC2-5300 RAM (it's a matter of marketing only, they said). I have to admit I'm skeptical, but I guess I'll give it a whirl. Can anybody confirm that fact?

[Eug Wanker]

Same thing. PC-5333 actually.

[mduell]

Yea, the difference between PC2-5400 and PC2-5300 is just a marketing thing; same as PC2-4300 and PC2-4200. I believe the JDEC standard says 5300.
A 64-bit wide bus at 666.666666667Mhz is 5333.33333MBps, so some mark it up and some mark it down.

Just to give you an idea of how many manufacturers do it each way, here are the number of modules available at NewEgg:
# DDR2 533 (PC2 4200) (87)
# DDR2 533 (PC2 4300) (5)
# DDR2 667 (PC2 5300) (68)
# DDR2 667 (PC2 5400) (36)

[selowitch]

Interesting, from Apple's iMac Developer Note for the iMac released on 09/7/066:

Memory
The iMac provides two RAM slots that accommodate 200-pin DDR2 SDRAM SO-DIMMs up to 1.25” in height. The SO-DIMMs must be DDR2 PC2-5300-compliant (emphasis mine) and must be unbuffered, unregistered, 8-byte, nonparity, and non-ECC. The iMac ships with two 512 MB DDR2 SDRAM SO-DIMMs for a total of 1 GB memory. Maximum memory capacity is 3 GB. Additional RAM must be installed in pairs of equal sizes.

Yet, in this document, they say:

iMac (Late 2006): Memory Specifications
This article outlines the memory specifications for the following products:
iMac (17-inch Late 2006)
iMac (20-inch Late 2006)
iMac (24-inch)

These iMac (Late 2006) computers have two SDRAM slots in the bottom of the computer, and comes with at least 512 MB DDR2 SDRAM installed into the top slot.

Although these iMacs will accept up to a 2 GB SO-DIMM in each of the two memory slots, the iMac will only support 3 GB total memory. If you want to maximize the amount of SDRAM in your computer, install a 2 GB SO-DIMM in one slot and a 1GB SO-DIMM in the other.

You can use Small-Outline Dual Inline Memory Modules (SO-DIMMS) that meet all of these criteria (emphasis mine):
PC2-5400
unbuffered
nonparity
200-pin
667 MHz
DDR2 SDRAM

But the PC2-5400 is not strictly a requirement, is it? I should tell Apple to clarify this.

[Eug Wanker]

Again... It's the same thing.

[selowitch]

Originally Posted by Eug Wanker

Again... It's the same thing.

Yes, you've established that. Unfortunately, the text on Apple's website does not make it clear that they're the same thing, which could lead to confusion, as it did in my case. I very nearly returned memory that I didn't need to return, for a very understandable reason.

And since two things with two different names are indeed "the same thing," Apple and others need to take special care to make sure folks don't become confused. Think of the average consumer in this scenario. It is reasonable for one to think that because "the same thing" goes by two different names that there might be an important technical difference? Anyway, my issue is with Apple's instructions, not the mere fact that PC2-5300 and PC2-5400 are functionally the same — I accept that much.

If you received a letter from Brian and a letter from Bryan who were the same person (but you didn't know that fact), would you wonder if they might be too different people? Of course you would.

We all know how brilliant you are, but some of us are mere mortals in need of clarity.

[zaghahzag]

Originally Posted by selowitch

Interesting, from Apple's iMac Developer Note for the iMac released on 09/7/066:Yet, in this document, they say:But the PC2-5400 is not strictly a requirement, is it? I should tell Apple to clarify this.

Originally Posted by apple

Memory
The iMac provides two RAM slots that accommodate 200-pin DDR2 SDRAM SO-DIMMs up to 1.25” in height. The SO-DIMMs must be DDR2 PC2-5300-compliant (emphasis mine) and must be unbuffered, unregistered, 8-byte, nonparity, and non-ECC. The iMac ships with two 512 MB DDR2 SDRAM SO-DIMMs for a total of 1 GB memory. Maximum memory capacity is 3 GB. Additional RAM must be installed in pairs of equal sizes.

now i'm confused.. does it have 2 dimms inside that each have 1 512, and then 2 more? How can you make a pair that has 3 gigs?

if there's 4 slots then i understand, but then by removing the two that are there already, you could put in 4.. or are they soldered down?

[ghporter]

Originally Posted by selowitch

Unfortunately, the text on Apple's website does not make it clear that they're the same thing, which could lead to confusion, as it did in my case.

Apple can and should do better than that. They could at least put a note on the page saying "the PC2 5400 is actually the same thing as PC2 5300 and the difference is merely in terminology." Anything to reduce customer confusion is a good thing, and that's kind of what we expect from Apple, isn't it? Good things for customers?

[selowitch]

Originally Posted by zaghahzag

now i'm confused.. does it have 2 dimms inside that each have 1 512, and then 2 more? How can you make a pair that has 3 gigs?

if there's 4 slots then i understand, but then by removing the two that are there already, you could put in 4.. or are they soldered down?

I don't think any of the iMac's RAM is soldered to the motherboard; there are two slots that can hold a total of 4GB of RAM physically, but in that case only 3GB of that will actually be addressed/used by the machine.

The interesting question this raises is, it is speedier to use two 2GB SO-DIMMs (matched pairs) or one 1GB SO-DIMM and one 2GB SO-DIMM (unmatched pair), since both combinations produce the same amount of usable RAM. And if the former is faster, would the speed gain be worth the additional cost (probably not)?

[imitchellg5]

Originally Posted by ghporter

Apple can and should do better than that. They could at least put a note on the page saying "the PC2 5400 is actually the same thing as PC2 5300 and the difference is merely in terminology." Anything to reduce customer confusion is a good thing, and that's kind of what we expect from Apple, isn't it? Good things for customers?

IMO Apple likes being nice and vague on things like that. They like customers to buy their RAM and upgrades, so they create a sense of confusion.

[selowitch]

Originally Posted by ghporter

Apple can and should do better than that. They could at least put a note on the page saying "the PC2 5400 is actually the same thing as PC2 5300 and the difference is merely in terminology." Anything to reduce customer confusion is a good thing, and that's kind of what we expect from Apple, isn't it? Good things for customers?

Thank you for coming to my defense. I was beginning to feel like the lone meshugenner in a roomful of sane people, you know what I mean?

[mduell]

The two documents were probably written by different people or groups.

I'm actually surprised how many modules are branded as 5400.

edit: Aha, it's just a few of the crappy RAM brands that are pushing a lot of different modules with the 5400 speed. Here's the brand breakdown from NewEgg:

5400: G.SKILL (15), OCZ Technology, Inc. (13), PQI (8)
5300: A-DATA (3), Aeneon (2), All Components, Inc. (4), Buffalo Technology (3), Corsair Memory, Inc. (4), Crucial Technology (9), GeIL (1), Kingmax (1), Kingston Technology (4), Mushkin (15), Patriot Memory (10), PNY Technologies, Inc. (1), SimpleTech (2), SUPER TALENT (2), Transcend (2), Viking (3), Wintec Industries (2).

The four most reputable brands in my opinion (Corsair, Crucial, Kingston, and Mushkin) are all in the 5300 camp.

[jamil5454]

I pulled the 2x 1GB PC2-5300 modules from my 1st gen Intel iMac and slapped them in my new Core 2 Duo iMac with no problems. All Apple did AFAIK was replace the Core Duo with a Core 2 Duo, since they are, after all, pin compatible.

[OmniX]

Originally Posted by jamil5454

I pulled the 2x 1GB PC2-5300 modules from my 1st gen Intel iMac and slapped them in my new Core 2 Duo iMac with no problems. All Apple did AFAIK was replace the Core Duo with a Core 2 Duo, since they are, after all, pin compatible.

No offense Jamil5454, but you may not know very far; at the very least, the C2D iMacs have a 3GB RAM ceiling, while I believe the first-gen CD iMacs had a 2GB RAM ceiling. This alone suggests at least some subtle changes in the logic board (memory controller? I don't know). There may be others as well. You are correct though that for the most part the original and current intel-iMacs seem quite similar on the inside.

[Eug Wanker]

It's nice to know that both my G5 2.0 iMac and my iMac C2D 2.33 both support VESA mounts. I'm tempted to get one for my G5 2.0 at work.

AFAIK, the other Intel or G5 iSight iMac models do not support VESA mounts.

P.S. Where is the best place in Canada to get VESA mounting arms?

[selowitch]

Originally Posted by Eug Wanker

AFAIK, none of the other iMac models support VESA mounts.

Waaaahhh!

Nope, they don't. It's too bad, because my 20" Core 2 Duo sure could use one.
The default height is just a little too high for me, but I'm stuck with it.

[jamil5454]

Originally Posted by OmniX

No offense Jamil5454, but you may not know very far; at the very least, the C2D iMacs have a 3GB RAM ceiling, while I believe the first-gen CD iMacs had a 2GB RAM ceiling. This alone suggests at least some subtle changes in the logic board (memory controller? I don't know). There may be others as well. You are correct though that for the most part the original and current intel-iMacs seem quite similar on the inside.

I'm willing to bet the first-gen Intel iMacs support 3GB as well.

[mduell]

Originally Posted by OmniX

No offense Jamil5454, but you may not know very far; at the very least, the C2D iMacs have a 3GB RAM ceiling, while I believe the first-gen CD iMacs had a 2GB RAM ceiling. This alone suggests at least some subtle changes in the logic board (memory controller? I don't know). There may be others as well. You are correct though that for the most part the original and current intel-iMacs seem quite similar on the inside.

They use the same chipset with the same memory controller. There may be a firmware difference between them.

[Eug]

Originally Posted by selowitch

Nope, they don't. It's too bad, because my 20" Core 2 Duo sure could use one.
The default height is just a little too high for me, but I'm stuck with it.

You'd really be annoyed by the 24" then. I find the 20" about the right height for me. The 24" is a couple of inches taller.

[ghporter]

Originally Posted by selowitch

Thank you for coming to my defense. I was beginning to feel like the lone meshugenner in a roomful of sane people, you know what I mean?

The point of "specifications" is to be specific. If one specification is semantically/electronically/technically equivalent to another, then that should be clear. There's no issue of anyone being meshugenner- (now I know how to spell that!) - it's about communicating or not communicating. Details are the entire core of computing-and the key to computer companies' success.