me confused ram

[limqareb]

can someone explain the diffence between

ddr1

ddr2

ddr3

ddr 400

ddr pc3200

help is repped

 

[0range]

pc 3200, pc 2700 ect, is a kind of ddr, ddr2 is goin to be the next ram coming suposidly, but amd is in the makin of usuing ddr3, but ddr3 wont be comin out anytime soon, some mobo;'s use ddr2 but now many

 

[limqareb]

ok 10x

 

[balilu]

DDR=Double Data Ram = i.e. sends to bits at the same time so if it is set in bios as 200mhz it will work as 400mhz effectivley

DDR2= this is same as above but is able to reach higher speeds easily

DDR3= this is same as above

DDR400 and PC3200 are the same thing but one is shown that it is running @ 400mhz effectivley and PC3200 is just a name i think.

 

[Dav0s]

DDR1 = the type of ram that most modern mobos use. a type of SDRAM that operates at "double data rate" (DDR) and so its theoretical speed is FSB x 2.

DDR2 = type of ram used on the latest intel chipsets - 9XX series. intel claim it is the latest and greatest. it is the same as DDR1 in msot cases but 240 pin i tihnk and just works in a different way.

read and enjoy http://www.sysxtreme.com/showthread.php?t=348

DDR3 = the latest type of memory that AMD has announced it wil be using.

DDR1/DDR2/DDR3 = all these can also be types of gfx card memory. try to not get confused.

DDR400 = PC3200 = a speed of DDR ram (all types). 400 refers to the double data rate so FSB x 2. Therefore rated to run at a FSB speed of 200.

 

[limqareb]

ok dave my gfx is 256 md ddr2 10x ppl

 

[Joe]

AN Excerpt from a guide i was working on AGEs ago but forgot all about

RAM

The purpose of RAM was outlaid in the basic info FAQ

All Ram is Currently DRAM

(For this FAQ I will not b going into ram older than 168-pin SDRAM as such ram us useless in relation to today’s systems)

SDRAM – Development ended; this was older ram used in most systems from the P2 era to early P4’s/ AXP’s;

It has 168-pins and a 32-bit wide bus the maximum official rated speed was 133 MHZ most latencies where in the 2-3 CAS range

DDR – essentially the same as SDRAM but send and receives Data on both the Rising and falling pulse of the Ram cycles … essentially acting @ double the speed of SDRAM it also requires additional connectors to prevent EMI crosstalk ‘aka’ interference occurring @ the new data rate

RDRIMM – ‘aka’ Rambus memory is extremely high latency/bandwidth RAM only realistically used in older P4 systems; although extremely fast has/had a high cost associated with it due to expensive licensing agreements – not really used in today’s systems

Memory speed:

Memory speed is measured in MHz, the we are dealing with DDR RAM then this speed is doubled to account for the ‘Double-pumping’- of the RAM bus;

E.G.

DDR Ram running @ 200 MHz is equivalent to 400 MHz SDR RAM (Single rate ‘aka’ standard SDRAM)

[font=&quot]The amount of data transfer per second capable with DDR running @ 200 MHz (‘aka’ 400 MHz SDR) is 400 * 8 <bytes> per cycle so 3200 MiB per second this is where [/font][font=&quot]the term PC3200 comes from when referring to RAM running @ DDR 400/200MHz[/font][font=&quot] [/font] Dual channel is a method where a computer system uses 2 independent 64-bit memory controllers to address 2 banks of memory of the same size as one of the combined size of both banks; thus creating a 128-bit interface for memory and so doubling memory bandwidth resulting in greater overall system performance.

E.G

Bank 1 - 256Mb and 256 Mb

Bank 2 - 512 Mb

-or-

Bank 1 - 512Mb

Bank 2 - 512Mb

these examples gives 1 GB of memory on a 128-bit memory bus

For this technique to work though you require that the memory has similar SPD data /clock timings - it if best

[font=&quot]

DDR2 and DDR3 is essentially the same as DDR ans SD (they CAN use the same silicon) except the DDR2 and 3 have got more pins and grounding wires to prevent EMI crosstalk allowing less interference thus allowing a higher FSB to be achievied but as the chips are basicallt the same as DDRs chips we loose latency @ the higher FSBs

[/font]

 

[|3ourne]

DDR 1 = Dual Data Rate , basically means the data is transferred between the chipset and memory or the cpu and memory in A64's case twice in one cycle. Meaning the ram is working at a theoretical twice the rated speed.

Now related to this is PC3200 / DDR400 and so on. These are the nomenclatures used for branding a memory module. PC3200 translates to DDR400 . So basically they are both the same speed. Now for a ram rated at DDR400 , its actual frequency is 200 mhz but since its DDR its apparent or shown speed is 400 mhz since it pumps data twice in one cycle.

Now DDR2 is the next step down the DDR line. Its got more pins than DDR and uses lesser voltage as well. However , for DDR2 to achieve tight timings its quite impossible. Their purpose is to generate high bandwidths at high speeds. Thus the tightest DDR2 in the market right now is rated at 3-2-2-8 timings at DDR540 . Intel uses DDR2 becoz the present DDR supposedly cannot provide the processor with enough bandwidth , which personally i feel is hogwash.

The only reason Intel did this is becoz they saw A64 utilizing DDR in a much more efficient way , which had them running to their drawing boards for another product they could hype up. Thus we got the DDR2 . Earlier DDR2 and DDR3 were only used on video cards , becoz video cards actually benefit from higher ram clocks than tighter timings. The 1200 mhz + overclocks that ppl get for their memories on video cards would not be possible had it not been for DDR2 or DDR3 .

Thus to summarize ,

DDR = relatively low speeds , but tighter timings and good bandwidth on right platform

DDR2 = High clock speeds ( around DDR700 most of the time ) but looser timings which takes away the advantage till DDR720 or higher .

DDR3 = Used mostly in today's fastest Graphics cards , provides insane bandwidths , is smaller and needs lesser voltage . Also runs looser timings than DDR and DDR2 but video cards are most sensitive to raw clocks than nething else.

Hope this helped .

 

[limqareb]

thanks for the help , repped you all (except dave , impossible to rep)now i understand