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hugodrax

macrumors 65816
Original poster
Jul 15, 2007
1,219
610
I saw a screenshot of SL activity monitor with lots of 64bit stuff like Calculator (why?) taking up double the RAM compared to the Apps I see running on Activity monitor now.


3614621591_593ce26052_o.jpg
 

spinnerlys

Guest
Sep 7, 2008
14,328
7
forlod bygningen
I saw a screenshot of SL activity monitor with lots of 64bit stuff like Calculator (why?) taking up double the RAM compared to the Apps I see running on Activity monitor now.
.....


Are you sure?

For me it's the opposite, Calculator takes up 26,43MB and Dictionary 45,52MB right after I just started them. (edit: in Leopard)
 

Saladinos

macrumors 68000
Feb 26, 2008
1,845
4
64-bit means that every long, pointer...etc takes twice the memory. It effectively doubles RAM usage.

From Wikipedia:
"The main disadvantage of 64-bit architectures is that relative to 32-bit architectures the same data occupies more space in memory (due to swollen pointers and possibly other types and alignment padding). This increases the memory requirements of a given process and can have implications for efficient processor cache utilization."

It sounds like something bogus made up by people who don't understand technology properly, but it's true. There are ways to reduce the effect, but I don't know if Apple are doing anything like this.
 

Catfish_Man

macrumors 68030
Sep 13, 2001
2,579
2
Portland, OR
It'll be interesting to see whether they manage to trim memory usage in other ways enough to counter out the effects of 64 bit. I'm hopeful :)


(I haven't tested yet... don't want to reboot into 10.5 to get numbers for memory usage there)
 

Miamifan1354

macrumors member
May 12, 2009
46
0
So if it uses double the ram, will my old 2.2ghz MBP which only supports 4gig ram be able to be upgraded to 8gig once 10.6 is installed? Like will 10.6 recognize 8 gig where 10.5 could only see 4?
 

dukebound85

macrumors Core
Jul 17, 2005
19,131
4,110
5045 feet above sea level
So if it uses double the ram, will my old 2.2ghz MBP which only supports 4ghz ram be able to be upgraded to 8ghz once 10.6 is installed? Like will 10.6 recognize 8 ghz where 10.5 could only see 4?

its gb, not ghz and no, if your computer only supports 4gigs, that all it will ever support

the ram increase is what leopard will need to use software wise

64-bit means that every long, pointer...etc takes twice the memory. It effectively doubles RAM usage.

From Wikipedia:
"The main disadvantage of 64-bit architectures is that relative to 32-bit architectures the same data occupies more space in memory (due to swollen pointers and possibly other types and alignment padding). This increases the memory requirements of a given process and can have implications for efficient processor cache utilization."

It sounds like something bogus made up by people who don't understand technology properly, but it's true. There are ways to reduce the effect, but I don't know if Apple are doing anything like this.
interesting so is the ram increase namely due to going to 64bit?

if i have a core duo machine and wont be utilizing 64 bit, would my ram requirements be below what apple reccomend at 1 gb, and be essentially 512mb?
 

Miamifan1354

macrumors member
May 12, 2009
46
0
its gb, not ghz and no, if your computer only supports 4gigs, that all it will ever support

the ram increase is what leopard will need to use software wise


interesting so is the ram increase namely due to going to 64bit?

if i have a core duo machine and wont be utilizing 64 bit, would my ram requirements be below what apple reccomend at 1 gb, and be essentially 512mb?

You're right.. Too many abbreviations. Thanks!
 

Saladinos

macrumors 68000
Feb 26, 2008
1,845
4
interesting so is the ram increase namely due to going to 64bit?

if i have a core duo machine and wont be utilizing 64 bit, would my ram requirements be below what apple reccomend at 1 gb, and be essentially 512mb?

Yes, the increase is due to 64-bit computing. Memory pointers can address more memory by being 64-bits long rather than 32-bits long. However, these pointers have to be stored, and since they're longer in the 64-bit system, they take more bits to store.

That means that 1Gb of RAM on 64-bit is like having 512Mb on 32-bit. However, there are other advantages, like some faster calculations and more registers which mean it's a bit faster than 512Mb on 32-bit.

This doesn't increase the amount of memory your computer can handle. So if you're computer (and your wallet) can handle a 2x RAM increase, and you have a 64-bit capable Mac, do that in preparation for Snow Leopard to be sure of a performance boost. Otherwise the lack of RAM might bottleneck application performance, depending on your usage.

For my Santa Rosa 2.4Ghz BlackBook, getting 4Gb of DDR2 notebook RAM (2x2Gb) is £40 from overclockers.co.uk. It's fairly inexpensive and will be well worth it.
 

DarkRyan323i

macrumors member
Mar 3, 2009
71
0
So does this mean that users who don't upgrade their RAM may actually see a decrease in performance? Or will Snow Leopard make up for the increased RAM usage some other way? I planned on upgrading to 8GB of RAM at some point but not for a quite a while.
 

Nikolai01

macrumors newbie
May 27, 2008
27
0
So does this mean that users who don't upgrade their RAM may actually see a decrease in performance? Or will Snow Leopard make up for the increased RAM usage some other way? I planned on upgrading to 8GB of RAM at some point but not for a quite a while.

I second this question. My Rev.1 C2D MBP can only handle 3gig max. I can't increase the RAM beyond that. Will I possibly see a decrease in performance upon upgrading to SL?
 

MacUser2525

Suspended
Mar 17, 2007
2,097
377
Canada
I second this question. My Rev.1 C2D MBP can only handle 3gig max. I can't increase the RAM beyond that. Will I possibly see a decrease in performance upon upgrading to SL?

You should see an increase in performance as the registers are twice as wide in 64bit mode allowing double the data to be processed during the same clock cycle, that is the theory anyways...
 
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