4Gb Ram is it worth?

[jota73]

I am about to order my 20" 2.4GHz iMac, and wanted to upgrade its RAM, I have read that having 4 GB RAM the total usable memory would be 3.3GB.

In other words.

Is it worth buying 2Dims of 2GB each to sum up 4GB when the usable would be 3GB or just buy 1 Dimm of 2g to sum up 3Gb, so that the total 3GB would be usable?

My post is based on what I read here

 

[superleccy]

* The maximum RAM is different for different logic boards:

1. Core 2 Duo Santa Rosa machines, (MacBook Pros and the new iMacs) can recognize a full 4 GB of RAM.
2. Earlier Core 2 Duo machines can recognize a potential 3.3 GB (with 2 x 2 GB installed... the top 700 MB is wasted, so the practical maximum is 3 Gb with 1 x 1 Gb and 1 x 2 Gb). This is a hardware limitation.
* With 4 GB installed, these machines will report 4 GB in System Profiler, but the operating system will only use 3.3 GB.

I believe that the new 2.4GHz iMacs have the Santa Rosa chipset (that's what the article seems to say anyway). Therefore, the first point would apply, and your new iMac would be able to "recognise a full 4GB of RAM".

SL

 

[caj]

2Dims of 2GB each to sum up 4GB, definatly

 

[jota73]

I believe that the new 2.4GHz iMacs have the Santa Rosa chipset (that's what the article seems to say anyway). Therefore, the first point would apply, and your new iMac would be able to "recognise a full 4GB of RAM".
SL

R U totally sure?

 

[jota73]

2Dims of 2GB each to sum up 4GB, definatly

not according to the text posted at Guides...in macrumors

 

[je1ani]

You're confusing the old white iMac C2Ds with the new Aluminum C2Ds with SR chipsets

 

[superleccy]

R U totally sure?

Yes. But don't sue me.

not according to the text posted at Guides...in macrumors

Read it again.

Consider also the following which I believe to be facts:

• The Core 2 Duo 2.4GHz processors are Santa Rosa-only.
• The previous generation of Core 2 Duo iMacs (non-Santa Rosa, maxed out at 2.33GHz) would only ship with a maximum of 3Gb RAM.

Also, you get better performance if your DIMM modules are of equal size, becuase they work in dual-channel mode (or something).

But again, don't sue me.

SL

 

[Sun Baked]

You're confusing the old white iMac C2Ds with the new Aluminum C2Ds with SR chipsets

Yep, the Napa chipset had the hardware DMA reside within the 4GB memory, and Santa Rosa chipset tossed it outside that. So the al-iMac is the full 4GB of memory.

Of course the max memory is awaiting the 4GB SO-DIMM test.