Santa Rosa Chipset - 2.4 Ghz - 800 mhz FSB vs. 667 mhz memory controller?

jasonnorm

macrumors regular
Original poster
Aug 10, 2007
111
0
Milford, MA
I am hoping someone can give me the correct answer here to ensure I spend my money wisely :)

I am looking to upgrade the memory on my new 24" 2.4 Ghz iMac. The memory for this chip set according to crucial.com is PC2-6400 (800 mhz). Now, I know that the PC2-5300 (667 mhz) memory is backwards compatible and will work on the system, but I do not want to loose performance by downgrading what I have in there already (PC2-6400).

I have heard however that although the Santa Rose chipset has a FSB of 800 mhz, the memory controller is limited to 667 mhz. This would mean that the PC2-6400 is not using the full 800 mhz as it would be limited by the memory controller's speed of 667 mhz. So, I could purchase the PC2-5300 memory and it would have NO negative impact on performance. Considering the PC2-5300 is cheaper (and is readily available in 2 GB dimms), I would like to know if the above is accurate or if I am truly getting 800 mhz out of the memory controller to match the FSB.

Thanks!
-Jason
 

daneoni

macrumors G4
Mar 24, 2006
10,803
79
I am hoping someone can give me the correct answer here to ensure I spend my money wisely :)

I am looking to upgrade the memory on my new 24" 2.4 Ghz iMac. The memory for this chip set according to crucial.com is PC2-6400 (800 mhz). Now, I know that the PC2-5300 (667 mhz) memory is backwards compatible and will work on the system, but I do not want to loose performance by downgrading what I have in there already (PC2-6400).

I have heard however that although the Santa Rose chipset has a FSB of 800 mhz, the memory controller is limited to 667 mhz. This would mean that the PC2-6400 is not using the full 800 mhz as it would be limited by the memory controller's speed of 667 mhz. So, I could purchase the PC2-5300 memory and it would have NO negative impact on performance. Considering the PC2-5300 is cheaper (and is readily available in 2 GB dimms), I would like to know if the above is accurate or if I am truly getting 800 mhz out of the memory controller to match the FSB.

Thanks!
-Jason
I think you're spot on.
 

Red-red

macrumors 6502
Jul 17, 2007
313
0
A quick question about the memory on the new imac. Many people seem to be going for the 1gb one and upgrading the memory them self but I want to know whether one or two of the ram slots are in the easy change part. Because Really if I am going to go for one of the new ones I want to get the best performance I can so the 4gb would be for me as working with high res images on photoshop im sure it would help but I don't want to pay the way overpriced way of the apple store opting to doing it my self. Now if I had to open it up it wouldn't matter to much as I am quite computer savy but just a question.
 

jasonnorm

macrumors regular
Original poster
Aug 10, 2007
111
0
Milford, MA
One screw, pull lever, pull out RAM, insert RAM.

VERY easy. Just ground yourself 1st

It's even in the little book that comes w/ the Mac. Just buy with 1 GB and buy your own RAM. Apple wants $1,000 for the 4 GB kit !! (WTF!!! :eek:)
 

daneoni

macrumors G4
Mar 24, 2006
10,803
79
A quick question about the memory on the new imac. Many people seem to be going for the 1gb one and upgrading the memory them self but I want to know whether one or two of the ram slots are in the easy change part. Because Really if I am going to go for one of the new ones I want to get the best performance I can so the 4gb would be for me as working with high res images on photoshop im sure it would help but I don't want to pay the way overpriced way of the apple store opting to doing it my self. Now if I had to open it up it wouldn't matter to much as I am quite computer savy but just a question.
RAM is easy to access and change. Just unscrew remove and install the sticks. My first go wasnt that easy but thats probably just me. Second round however....piece of cake
 

Jimmdean

macrumors 6502
Mar 21, 2007
407
139
Looks like the old crucial screwjob. They're just showing you all the compatible memory, hoping you'll pay more for the faster speed, even though they know the system has a technical limit of 667MHz. I also noticed they are charging quite a bit more for their 800MHz memory. Go with the 667MHz.
 

rds

macrumors regular
Aug 9, 2007
148
0
Like I've mentioned previously, when using a memory configuration wizard jobby, pick any of the latest MacBook Pro's over the mid 2007 iMac as the results are more accurate.
 

oduinnin

macrumors regular
Aug 3, 2007
139
0
Planet Earth
Looks like the old crucial screwjob. They're just showing you all the compatible memory, hoping you'll pay more for the faster speed, even though they know the system has a technical limit of 667MHz. I also noticed they are charging quite a bit more for their 800MHz memory. Go with the 667MHz.
Go here: OWC Memory

These folks have never steered me wrong and their prices are decent. :)
 

stockcerts

macrumors 65816
Jun 29, 2007
1,278
14
San Francisco, CA
I have a new Imac and if I understand the configuration, there are two slots and one of my two has a 1 gig module in it now. Can I then buy a two gig module and put it in the empty slot to bring me up to 3gigs?

I'm still not sure of the best place to buy the memory. It seems like Crucial is the recommended brand. Does anyone have an exact part number and preferred vendor? Thanks!

BTW...I love my new IMac!
 

roland.g

macrumors 604
Apr 11, 2005
6,538
1,452
I just got my 2x2GB sticks from OWC, ordered Wed, arrived Mon UPS ground, $2.95 shipping, $234 total.

With the money I saved by selecting the $1,799 iMac with 1GB and upping the CPU to 2.8 rather than taking the 2.8Ghz stock which comes with 2GB, it ended up costing me $73 more all said and done to get the 2.8 with 1GB and order 4GB OWC than if I ordered the 2.8 stock option that comes with 2GB. And yes that was with the same size HDD selected for both. If you pick the 2.4 and change the CPU you need to change the HDD to 500 to match the 2.8 stock model. I opted for the 750.

2.8Ghz 24" iMac with 1GB RAM 750GB HDD and BT MM - $2,319 + tax shipped.
4GB OWC RAM - $234 shipped.

2.8Ghz 24" iMac with 2GB RAM 750GB HDD and BT MM - would have been $2,469 + tax.
 

daneoni

macrumors G4
Mar 24, 2006
10,803
79
I have a new Imac and if I understand the configuration, there are two slots and one of my two has a 1 gig module in it now. Can I then buy a two gig module and put it in the empty slot to bring me up to 3gigs?

I'm still not sure of the best place to buy the memory. It seems like Crucial is the recommended brand. Does anyone have an exact part number and preferred vendor? Thanks!

BTW...I love my new IMac!
Yes it would bring you to 3GB. Crucial and OWC seem to be the preferred choice.
 

Red-red

macrumors 6502
Jul 17, 2007
313
0
I just worked out that with my student discount I could get:

24" imac
2.8ghz
4gb (ordering from crucial)
with cover

For around £1450.


Not bad.