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3gb vs 4gb

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July 16, 2009 7:35:58 AM

on a 32-bit system (vista), 2x2gb of ram will never show up as 4gb right? so is it worth having a (2+1) 3gb ram config over a (2+2) 4gb ram config, bearing in mind vista will prolly recognize 3 gb in either case?
also, will 4gb of ram work in dual channel in 32-bit systems? it may only show 3gb, but will dual channel mode be activated? coz im buying a notebook soon, n they all come with (2+1) 3gb ram n vista 32 bit so i wanna kno whether its worth getting 2x2gb, even if it still recongizes around 3.5gb max ram space.
uzair

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a b } Memory
July 16, 2009 7:59:17 AM

my comp shows 3.5 in xp or win 7 and runs in dual channel 2 2gig sticks
July 16, 2009 8:07:29 AM

k thx. but wat abt in vista? n ive heard sometimes the os subtracts the amount of ram ur gcard has from the total amount of ram..like if ur pc has a 512mb gcard, then ur os would show 3gb, not 3.5gb like u just said. is that tru, coz my notebook will be shipped with a 1gb radeon 4650.
also, should i upgrade my ram from 3gb to 4gb in my notebook? is the performance worth the lil extra cost?
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a b } Memory
July 16, 2009 9:46:12 AM

exist2inspire said:
...is it worth having a (2+1) 3gb ram config over a (2+2) 4gb ram config, bearing in mind vista will prolly recognize 3 gb in either case?
also, will 4gb of ram work in dual channel in 32-bit systems? it may only show 3gb, but will dual channel mode be activated?...

No, go with the 2x4Gb option.
If you have two mismatched sticks, your RAM will not run in dual channel mode.
With two matched sticks, it will run in dual channel mode regardless of the operating system (it is hardware level not driver level).
exist2inspire said:
...ive heard sometimes the os subtracts the amount of ram ur gcard has from the total amount of ram..like if ur pc has a 512mb gcard, then ur os would show 3gb, not 3.5gb like u just said. is that tru, coz my notebook will be shipped with a 1gb radeon 4650.
also, should i upgrade my ram from 3gb to 4gb in my notebook? is the performance worth the lil extra cost?

Kinda yes...
A 32 bit Os it capable of addressing a total of 4Gb of memory.
This includes system RAM, video RAM, the BIOS and all other memory/caches connected to the motherboard.
When you have more than 4Gb of memory running in your system you will allocate to all devices before you allocate the system RAM.
So, the total available to use in Windows will = 4Gb - (GPU RAM) - (possible sound card RAM) - BIOS - a small amount for system caches.
In practice, if you have 4Gb of RAM installed and a 512Mb GPU, you will have a little under 3.5Gb available to the operating system.

You should defiantly go for the 4Gb option (assuming it does not cost to much more) as it will allow you to run the RAM in dual channel mode for a doubling of your memory bandwidth.
Also, see if you have the option to get a 512Mb 4650 or Vista x64.
Either way, you will be able to access more of your RAM with no detrimental effects to your performance.
a b } Memory
July 16, 2009 1:37:25 PM

old 32 bit operating systems are limited to 4 gigs total system ram, including video. 1 gig of video, 4 gigs of system = 5 gigs total, so you would lose a gig. this is not the case in 64 bit systems, or 32bit win7.
July 16, 2009 3:34:37 PM

I'm looking at this closely and there is another consideration for slightly older systems. Mine is a Socket 939 mobo by ASUS with an Athlon 64 x2 4400+ CPU. That system puts the RAM control in the CPU itself. The mobo has 4 RAM sockets that will automatically adjust to Single- or Dual-channel mode, depending on how they are filled. Optimal is putting matched pairs in each set of slots to use Dual-Channel. This board / CPU system uses DDR SDRAM - mine is GSkill modules of PC3200, which runs at 400 MHz. So far the largest DDR SDRAM modules I have found are 1 GB each, double-sided.

Now the mobo manual cautions that, if you choose to populate all four RAM slots with double-sided modules, it will automatically reduce the RAM speed from 400 to 333 MHz. Near as I can tell, this is because that much RAM loads the address and data lines enough to make the signals weaker and harder to read, so slowing it down gives the system reliable signals. Net result is if I go to 4 x 1GB double-sided DDR SDRAM rated at PC3200, the mobo will slow down the RAM to 333 MHZ, which is like using PC2600-rated RAM. That loss of RAM speed for ALL operations will surely wipe out any speed advantage possible from limited uses that exceed 1.5 GB of RAM use simultaneously. So unless I can beat the automatic slowdown of RAM use in that system, there is NO incentive for me to go from 2 to 4GB. Anyone else looking at RAM expansion should look carefully at their mobo manual and see if such a limitation applies to their system.
a b } Memory
July 16, 2009 5:08:00 PM

neon neophyte said:
old 32 bit operating systems are limited to 4 gigs total system ram, including video. 1 gig of video, 4 gigs of system = 5 gigs total, so you would lose a gig. this is not the case in 64 bit systems, or 32bit win7.


do you want to quote a source for that info
a b } Memory
July 16, 2009 5:53:22 PM

er, ok. i didnt just google it, so im going to google FOR you. its pretty common knowledge 32 bit operating systems are restricted to 4 gigs of ram.

http://www.tomshardware.com/reviews/vista-workshop,1775...

give that a lil once over i guess. its not where i learned it, but it references the 4 gig limit on 32 bit systems. it also references that there is no 4 gig restriction of 64 bit. (im not entirely sure on the memory restrictions of 64 bit xp, ive never used it, never researched it.)

now, to find where it says 32 bit win 7 isnt restricted (to 4 gigs), i didnt read it, ive just used win7.

http://alexmillsonline.blogspot.com/2008/10/windows-7-3...

next time, do your own google. *sigh*

*edit* also, im not looking for an argument. i know there are exceptions to this rule. like mac os' or whatever. probably linux or unix or WHATEVER.

im pretty much strictly referring to windows operating systems.
a b } Memory
July 16, 2009 6:43:13 PM

yes it is common knowledge that 32 bit os's can use 4 gig of ram that's why i was surprised to hear someone say "1 gig of video, 4 gigs of system = 5 gigs "

all 32 bit os's are limited to 4gig: xp vista and win 7
xp 64 supports 128
vista 64 8-128 depending on version
win7 64 8-192 once again depending on version

Further these64 bit memory limitations were implemented by Microsoft and are not limitations of the architecture like the 32 bit os's


So while your googling all that for me could you please show me where you found a reference to either 32bit os's supporting 5gig or win7 32 supporting more than 4gig. Because I have done a lot of research and have never seen reference to either of your statements anywhere.

Thank you kindly for your time i look forward to learning something new.
a b } Memory
July 16, 2009 6:45:44 PM

1 gig of video ram + 4 gigs of system ram = 5 gigs of total ram. with the restrictions of 32 bit systems, you would lose 1 gig. how is that hard to follow?

"1 gig of video, 4 gigs of system = 5 gigs total, so you would lose a gig." would be the exact words you are trying to rip apart.

good to know im googling for you because you cant read and comprehend what im saying.
a b } Memory
July 16, 2009 6:50:55 PM

ouch some how i missed the line "you would lose a gig" my mistake
to used to skimming thorough these

!