C2D Napa...64-Bit Ready or not?

[netdog]

Not that I am going to upgrade, but when I bought a C2D Napa machine, everyone here insisted that this was finally the true 64-bit Mac that would support Leopard best. Now I am reading that SR is the first true 64-bit capable Mac.

Please, if somebody who really knows the ins and outs could tell me what gives, and what the real world advantages of SR are in terms of 64-bit performance and capabilities, I would really appreciate it! :D

[EricNau]

Both are Core 2 chips, and yes, I believe both are 64 bit.

[daneoni]

Not that I am going to upgrade, but when I bought a C2D Napa machine, everyone here insisted that this was finally the true 64-bit Mac that would support Leopard best. Now I am reading that SR is the first true 64-bit capable Mac.

Please, if somebody who really knows the ins and outs could tell me what gives, and what the real world advantages of SR are in terms of 64-bit performance and capabilities, I would really appreciate it! :D

The only difference is that SR can address more than the 3GB RAM Napa does. Both (with Core 2 Duo chips) are still 64-Bit ready.....top to bottom.

[netdog]

Thank you :)

[roland.g]

Yes as I understand it, 64 bit can address more than 4GB of RAM, but does not require it. So a 64 bit CPU works with Leopard, whether Merom or Penryn, and on a Napa or Santa Rosa chipset. And SR allows for more than 4GB of RAM, so technically when there are 4GB sticks, you could have 8GB total in a 2 slot SR machine like a new MBP. Of course the Xeon Mac Pros have had more than 4GB capacity since their inception.

[booksacool1]

Yes as I understand it, 64 bit can address more than 4GB of RAM, but does not require it. So a 64 bit CPU works with Leopard, whether Merom or Penryn, and on a Napa or Santa Rosa chipset. And SR allows for more than 4GB of RAM, so technically when there are 4GB sticks, you could have 8GB total in a 2 slot SR machine like a new MBP. Of course the Xeon Mac Pros have had more than 4GB capacity since their inception.

Yeah there was a chipset limitation in Napa. 3-3.2gb tended to be the max. Its a bit of a problem because most people probably have their Napa MBP's with 2gb and will be annoyed when they find out they have virtually no upgrade options.

As for 64bit, both Napa and SR support it provided you have a Merom/C2D cpu. The original Core Duo's were not 64bit (even though they are part of Napa).

[gaelan]

Yeah there was a chipset limitation in Napa. 3-3.2gb tended to be the max. Its a bit of a problem because most people probably have their Napa MBP's with 2gb and will be annoyed when they find out they have virtually no upgrade options.

As for 64bit, both Napa and SR support it provided you have a Merom/C2D cpu. The original Core Duo's were not 64bit (even though they are part of Napa).

do they make 1.5GB RAM sticks? i figure 2GB is sufficient for most iMacs, but what is the best way to max out a napa machine? 2 - 1GB sticks or 2-2GB sticks?

[roland.g]

do they make 1.5GB RAM sticks? i figure 2GB is sufficient for most iMacs, but what is the best way to max out a napa machine? 2 - 1GB sticks or 2-2GB sticks?

1x1GB and 1x2GB.

[gaelan]

1x1GB and 1x2GB.

so what's the best way to max out the RAM in the current iMac? 2 one gig sticks or 2 two gig sticks OR a mix of both to total 3 gigs? i understand the limit on napa is 3.2, so it seems silly to waste the other .8 of RAM

[roland.g]

so what's the best way to max out the RAM in the current iMac? 2 one gig sticks or 2 two gig sticks OR a mix of both to total 3 gigs? i understand the limit on napa is 3.2, so it seems silly to waste the other .8 of RAM

a mix. one 1GB and one 2GB. That's what Apple does if you configure for 3. Don't try to get that extra .2 and don't worry about matched pairs, the advantage of 3GB vs. 2GB outweighs the disadvantage of having different size sticks. The performance gain of matched pairs is minimal.

[gaelan]

a mix. one 1GB and one 2GB. That's what Apple does if you configure for 3. Don't try to get that extra .2 and don't worry about matched pairs, the advantage of 3GB vs. 2GB outweighs the disadvantage of having different size sticks. The performance gain of matched pairs is minimal.

cool...thanks.

so what kind of performance advantage can the average end user expect from frontside bus speeds of 800 MT/s vs a 667 MT/s? I pulled these numbers from the Wiki entry comparing Napa and Santa Rosa.

[flopticalcube]

Money no object, the best solution is 2 X 2GB matched pair but you will waste almost half of one stick for a very small gain in performance.

[flopticalcube]

cool...thanks.

so what kind of performance advantage can the average end user expect from frontside bus speeds of 800 MT/s vs a 667 MT/s? I pulled these numbers from the Wiki entry comparing Napa and Santa Rosa.

Less than the 20% implied by the increase. IIRC, real world tests showed an increase of about 9%.