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<blockquote data-quote="Mattlike" data-source="post: 557346" data-attributes="member: 16580"><p>This may confuse or this may help, heh. (example/explanation)</p><p></p><p></p><p><strong><em><span style="color: Blue">Standard' RAM chips are organized a DEPTH x 8 Bits. E.g. 32x8, 64x8,</span></em></strong></p><p><strong><em><span style="color: Blue">etc. That means 8 of the chips make up a 64 bit wide rank (memory bus</span></em></strong></p><p><strong><em><span style="color: Blue">is 64 bits wide). "Double Sided" is an old term to describe a stick</span></em></strong></p><p><strong><em><span style="color: Blue">with 16 chips, 8 on each side. And with DEPTH x 8 chips that makes for</span></em></strong></p><p><strong><em><span style="color: Blue">2 ranks (or, again in an older style terminology: 2 'banks').</span></em></strong></p><p> <strong><em><span style="color: Blue"></span></em></strong></p><p><strong><em><span style="color: Blue">'High Density' chips are DEPTH x 4 bits so it takes 16 to make a 64</span></em></strong></p><p><strong><em><span style="color: Blue">bit wide memory rank. And this is why "double sided" is no longer the</span></em></strong></p><p><strong><em><span style="color: Blue">favored description because when x8 chips are used "Double sided"</span></em></strong></p><p><strong><em><span style="color: Blue">means "double rank" but with x4 chips it takes both sides and 16 chips</span></em></strong></p><p><strong><em><span style="color: Blue">to make the ONE, single, rank.</span></em></strong></p><p> <strong><em><span style="color: Blue"></span></em></strong></p><p><strong><em><span style="color: Blue">Now to the problem. A memory 'slot' is usually designed for 'standard'</span></em></strong></p><p><strong><em><span style="color: Blue">x8 chips and memory sticks containing 2 ranks. That is how the</span></em></strong></p><p><strong><em><span style="color: Blue">'capacity' will be described. I.E. the K7S5A says it can handle up to</span></em></strong></p><p><strong><em><span style="color: Blue">"1 gig" with two DDR slots, and that means 512Meg per slot, which</span></em></strong></p><p><strong><em><span style="color: Blue">means 256 Meg PER RANK. (2 ranks per slot, 2 slots, etc)</span></em></strong></p><p> <strong><em><span style="color: Blue"></span></em></strong></p><p><strong><em><span style="color: Blue">But a 'high density' memory stick crams the 512 Meg into ONE RANK by</span></em></strong></p><p><strong><em><span style="color: Blue">using 16 deeper (twice as deep) x4 bit width chips. And this is how</span></em></strong></p><p><strong><em><span style="color: Blue">they arrive at the confusing term 'high density'. The chips themselves</span></em></strong></p><p><strong><em><span style="color: Blue">are no higher in density than the x8 chips but since they are</span></em></strong></p><p><strong><em><span style="color: Blue">organized as x4 they can cram more 'bytes' into a single rank because</span></em></strong></p><p><strong><em><span style="color: Blue">16 chips make up a rank rather than 8, not that it helps make the</span></em></strong></p><p><strong><em><span style="color: Blue">stick itself any 'higher' in 'density' because you can still only get</span></em></strong></p><p><strong><em><span style="color: Blue">16 chips mounted on the thing.</span></em></strong></p><p> <strong><em><span style="color: Blue"></span></em></strong></p><p><strong><em><span style="color: Blue">So, a 512 Meg 'high density' stick puts 512 Meg in ONE RANK and a</span></em></strong></p><p><strong><em><span style="color: Blue">'standard' density 512 Meg stick is two 256 Meg Ranks. Same size, same</span></em></strong></p><p><strong><em><span style="color: Blue">'density'. It's the RANK organization that's different.</span></em></strong></p><p> <strong><em><span style="color: Blue"></span></em></strong></p><p><strong><em><span style="color: Blue">Since the memory slot on a K7S5A is two 256 Meg Ranks, a standard</span></em></strong></p><p><strong><em><span style="color: Blue">density 512 Meg stick will work but a 'high density' 512 Meg stick</span></em></strong></p><p><strong><em><span style="color: Blue">will not.</span></em></strong></p><p> <strong><em><span style="color: Blue"></span></em></strong></p><p><strong><em><span style="color: Blue">However, a 'high density' 256 Meg stick probably will since it crams</span></em></strong></p><p><strong><em><span style="color: Blue">the 256 Meg into ONE RANK and the K7S5A can handle 256 Meg ranks.</span></em></strong></p><p> <strong><em><span style="color: Blue"></span></em></strong></p><p><strong><em><span style="color: Blue">For example, I'm running SDRAM on my K7S5A and, as it turns out, one</span></em></strong></p><p><strong><em><span style="color: Blue">is 'standard' x8 density and the other is 'high density x4. But</span></em></strong></p><p><strong><em><span style="color: Blue">they're both 256 Meg sticks and they both work. **** irritating,</span></em></strong></p><p><strong><em><span style="color: Blue">however, as they were both bought at the same time inside the same</span></em></strong></p><p><strong><em><span style="color: Blue">package label, and same part number, with 16 chips on each so they</span></em></strong></p><p><strong><em><span style="color: Blue">look identical (Kingston) but they are NOT the same thing. Doesn't</span></em></strong></p><p><strong><em><span style="color: Blue">matter to my K7S5A but it means I can not use the 'high density' one</span></em></strong></p><p><strong><em><span style="color: Blue">in my other motherboards because they support 128 Meg ranks (256 Meg</span></em></strong></p><p><strong><em><span style="color: Blue">per slot but NOT in 'high density').</span></em></strong></p><p> <strong><em><span style="color: Blue"></span></em></strong></p><p><strong><em><span style="color: Blue">So, in a nutshell, if you're looking for 512 Meg sticks, make sure the</span></em></strong></p><p><strong><em><span style="color: Blue">spec says they use x8 chips. But, if you're not trying to get 1 gig</span></em></strong></p><p><strong><em><span style="color: Blue">then two 256 meg 'high density' sticks will be cheaper.</span></em></strong></p></blockquote><p></p>
[QUOTE="Mattlike, post: 557346, member: 16580"] This may confuse or this may help, heh. (example/explanation) [B][I][COLOR="Blue"]Standard' RAM chips are organized a DEPTH x 8 Bits. E.g. 32x8, 64x8, etc. That means 8 of the chips make up a 64 bit wide rank (memory bus is 64 bits wide). "Double Sided" is an old term to describe a stick with 16 chips, 8 on each side. And with DEPTH x 8 chips that makes for 2 ranks (or, again in an older style terminology: 2 'banks'). 'High Density' chips are DEPTH x 4 bits so it takes 16 to make a 64 bit wide memory rank. And this is why "double sided" is no longer the favored description because when x8 chips are used "Double sided" means "double rank" but with x4 chips it takes both sides and 16 chips to make the ONE, single, rank. Now to the problem. A memory 'slot' is usually designed for 'standard' x8 chips and memory sticks containing 2 ranks. That is how the 'capacity' will be described. I.E. the K7S5A says it can handle up to "1 gig" with two DDR slots, and that means 512Meg per slot, which means 256 Meg PER RANK. (2 ranks per slot, 2 slots, etc) But a 'high density' memory stick crams the 512 Meg into ONE RANK by using 16 deeper (twice as deep) x4 bit width chips. And this is how they arrive at the confusing term 'high density'. The chips themselves are no higher in density than the x8 chips but since they are organized as x4 they can cram more 'bytes' into a single rank because 16 chips make up a rank rather than 8, not that it helps make the stick itself any 'higher' in 'density' because you can still only get 16 chips mounted on the thing. So, a 512 Meg 'high density' stick puts 512 Meg in ONE RANK and a 'standard' density 512 Meg stick is two 256 Meg Ranks. Same size, same 'density'. It's the RANK organization that's different. Since the memory slot on a K7S5A is two 256 Meg Ranks, a standard density 512 Meg stick will work but a 'high density' 512 Meg stick will not. However, a 'high density' 256 Meg stick probably will since it crams the 256 Meg into ONE RANK and the K7S5A can handle 256 Meg ranks. For example, I'm running SDRAM on my K7S5A and, as it turns out, one is 'standard' x8 density and the other is 'high density x4. But they're both 256 Meg sticks and they both work. **** irritating, however, as they were both bought at the same time inside the same package label, and same part number, with 16 chips on each so they look identical (Kingston) but they are NOT the same thing. Doesn't matter to my K7S5A but it means I can not use the 'high density' one in my other motherboards because they support 128 Meg ranks (256 Meg per slot but NOT in 'high density'). So, in a nutshell, if you're looking for 512 Meg sticks, make sure the spec says they use x8 chips. But, if you're not trying to get 1 gig then two 256 meg 'high density' sticks will be cheaper.[/COLOR][/I][/B] [/QUOTE]
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