3gb vs 4gb

[exist2inspire]

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

 

[Ben90]

Im fairly sure that 2+1 will yield single channel mode. Things might be different for laptops since i don't work with them consistently so you might want to try contacting the manufacture, but my guess is that the BEST that will happen would be dual channel up until ~2 gigs memory usage (pretty much always with vista). Most likely though 2x1 will be single channel always and for this fact i would much rather go the 2x2 route even if the .5 Gb gets wasted.

 

[Paperdoc]

Until recently, the way to get faster RAM performance was Dual Channel. You place matched pairs of RAM modules in two slots and the system accesses it alternately, eliminating some wait states. But so often now I am seeing systems with 3 slots - not 2, not 4. So clearly they did NOT plan for alternating in matched pairs for all of the RAM. So I start speculating on how this works, and four possibilities come to mind. Maybe they use Dual Channel on the first two, and Single Channel on the last one? Maybe they use Dual Channel in the last module by alternating between the first and second halves of the same module? Maybe they are using something like Triple Channel? Maybe there is no Dual Channel operation at all? Or maybe there's some other design. But I do find it hard to believe the systems are designed with no consideration at all for this, and no use of Dual Channel anywhere. So I do not suppose that three-slot systems automatically mean only Single-Channel RAM use. Anyone out there know exactly how it really works?

4 GB of RAM does work in Dual-Channel systems with a 32-bit OS. The limit is in the OS: it can only generate addresses to access the RAM up to 4GB. Now, some of that real RAM space is reserved for use by the OS itself. Further, the OS must be able to access RAM on the video system, so it allocates a certain range of addressing to access that RAM, and the mobo RAM in that range simply does not get used at all. The net result is that the actual mobo RAM that CAN be used for applications is the original 4MB (or less, if that's what you have) minus the addressing areas reserved for those OS functions. So yes, if you install 4GB of RAM it can be used in a 32-bit OS, but some of it actually will not be available to your applications. And yes, if you have matched pairs of RAM modules in the paired slots, the memory will run in Dual Channel mode.

 

[TemjinGold]

It is worth having 2X2. It is however, NOT worth getting 2x2 preinstalled if you are buying a notebook as they rip you off for the ram (they charge up to a couple hundred more while a 2x2 kit will cost you ~$30AR or less on sale.) For notebooks, the best advice is to get it with the least amount of ram allowed installed, then buy your own 2X2 kit and put it in yourself. This will save you $100 or more depending on who you buy from.

 

[Ben90]

Originally posted by: Paperdoc
Until recently, the way to get faster RAM performance was Dual Channel. You place matched pairs of RAM modules in two slots and the system accesses it alternately, eliminating some wait states. But so often now I am seeing systems with 3 slots - not 2, not 4. So clearly they did NOT plan for alternating in matched pairs for all of the RAM. So I start speculating on how this works, and four possibilities come to mind. Maybe they use Dual Channel on the first two, and Single Channel on the last one? Maybe they use Dual Channel in the last module by alternating between the first and second halves of the same module? Maybe they are using something like Triple Channel? Maybe there is no Dual Channel operation at all? Or maybe there's some other design. But I do find it hard to believe the systems are designed with no consideration at all for this, and no use of Dual Channel anywhere. So I do not suppose that three-slot systems automatically mean only Single-Channel RAM use. Anyone out there know exactly how it really works?

once again I'm not an expert, but i remember seeing Intels own x58 board with 4 slots of ram. What happened was the board ran in triple channel mode until the first three sticks could not hold any more information, once the 3gb (in a 4x1 setup) or 6gb (4x2) limit was hit, the board drops down into dual channel and utilizes all 4 sticks at the expense of slightly less bandwidth

 

[Emulex]

superspeed ramdisk plus and windows 2003/8 enterprise 32bit can utilize the ram.

 

[soccerballtux]

Originally posted by: Ben90

Originally posted by: Paperdoc
Until recently, the way to get faster RAM performance was Dual Channel. You place matched pairs of RAM modules in two slots and the system accesses it alternately, eliminating some wait states. But so often now I am seeing systems with 3 slots - not 2, not 4. So clearly they did NOT plan for alternating in matched pairs for all of the RAM. So I start speculating on how this works, and four possibilities come to mind. Maybe they use Dual Channel on the first two, and Single Channel on the last one? Maybe they use Dual Channel in the last module by alternating between the first and second halves of the same module? Maybe they are using something like Triple Channel? Maybe there is no Dual Channel operation at all? Or maybe there's some other design. But I do find it hard to believe the systems are designed with no consideration at all for this, and no use of Dual Channel anywhere. So I do not suppose that three-slot systems automatically mean only Single-Channel RAM use. Anyone out there know exactly how it really works?

once again I'm not an expert, but i remember seeing Intels own x58 board with 4 slots of ram. What happened was the board ran in triple channel mode until the first three sticks could not hold any more information, once the 3gb (in a 4x1 setup) or 6gb (4x2) limit was hit, the board drops down into dual channel and utilizes all 4 sticks at the expense of slightly less bandwidth

Now that is strange.

Just fyi for all interested-- 64bit with 4GB of ram won't net you extra space over 32bit with 3GB-- the 64bit addresses take up more space. Once you get to 6GB or more 64bit is worth it (it may also be worth it to you for ease of ram upgrade factor). Tomshardware ran something on this a while back...

 

[Emulex]

use 3x2gb for 6gb and 1 socket for best speed.