idiots question about DDR2

[ives]

Hi,

I have an old pc that runs an XP Barton 2500+ with PC3200 ram.
I don't know what sort of ram this is.
Would it be DDR or DDR2?

Also, is there a big performance increase in using DDR2 over DDR?


Thanks

 

[[timko]]

Your Barton rig will have DDR ram.

DDR ram has 184pins whilst DDR2 has 240pins so you can't put one type in the other's slot, in other words you can't use DDR2 on your Barton setup.

http://en.wikipedia.org/wiki/DDR_RAM

http://en.wikipedia.org/wiki/DDR2_SDRAM

 

[Tetras]

Also, is there a big performance increase in using DDR2 over DDR?

Not applicable in your case anyway but in a word: no.

 

[ives]

thanks guys.
That's very helpful to know.


So just out of interest, why has the architecture structure changed if there's no performance difference?

cheers

 

[[timko]]

why has the architecture structure changed if there's no performance difference?

Read this link, which I gave above...

http://en.wikipedia.org/wiki/DDR2_SDRAM

The advantage of DDR2 over DDR SDRAM is the ability for much higher clock speeds, due to design improvements. With a clock frequency of 100 MHz, "SDR-SDRAM" transfers data on every rising edge of the clock pulse, thus achieving an effective 100 MHz data transfer rate. Unlike SDR, both DDR and DDR2 are double pumped; they transfer data on the rising and falling edges of the clock, at points of 0.0 V and 2.5 V (1.8 V for DDR2), achieving an effective rate of 200 MHz (and a theoretical bandwidth of 1.6 GB/s) with the same clock frequency. DDR2's clock frequency is further boosted by electrical interface improvements, on-die termination, prefetch buffers and off-chip drivers. However, latency is greatly increased as a trade-off. The DDR2 prefetch buffer is 4 bits wide, whereas it is 2 bits wide for DDR and 8 bits wide for DDR3.

Power savings are achieved primarily due to an improved manufacturing process, resulting in a drop in operating voltage (1.8 V compared to DDR's 2.5 V). The lower memory clock frequency could also help — DDR2 can use a real clock frequency 1/2 that of SDRAM whilst maintaining the same bandwidth.

 

[Hamoodii]

No DDR1

 

[ives]

thanks

 

[grs_link]

here is another article from anandtech...

they use nice table and graphs which are quite easy to understand...

u'll see that ddr2 is more effective as the FSB get higher..

read from the page I give you onwards...

http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=2741&p=3

 

[ives]

Interesting read.
Some of it went over my head, but it seems that, in general, the performance gains of DDR2 isn't that great over DDR.

 

[[timko]]

but it seems that, in general, the performance gains of DDR2 isn't that great over DDR.

Whilst the performance jump between each revision may not be that great, one of the more important issues is that as DDR technology grows, DDR2, DDR3 etc the amount of voltage it requires goes down. DDR runs at 2.5v, DDR2 at 1.8v and DDR3 1.5v. Less voltage requirements means lower power usage, less heat generated and potentially higher overclocks as well.

 

[grs_link]

ives.. sorry my bad...

wrong article... although descent.

have a look at the table of the first graph in this page:

http://www.anandtech.com/memory/showdoc.aspx?i=2809&p=6

u 'll see that from a bandwidth of 4800 goes up to 6400

my ddr xms4400 does 4700 at 200fsb and 5700 at 240fsb
over that i havent really test it.. bbut it wont go over 6000~6200 as this is the physical limitation of the bus ddr motherboard use..

if you read the frist article i gave you u'll see that at some point the say that ddr riched a 87-93% bus efficiency

DDR2 is currently only 45-60% which means before ddr3 comes along.. will see a noticable improvement of ddr2. both on mem dims and mobos.

generally if you are thinking to upgrade sometime soon.. imo it is wise to go for a dd2 setup. and trust me u wont regret it