DDR 400 or DDR2 667?????

[Alcpone]

I am getting (tomorrow) lol a new mobo which supports upto ddr 400 and ddr2 667!

I have to 2 sticks of elixir 512mb ddr 400 Access Time (NS) 5.0 CAS 3.0

I want to get 2 sticks of 512MB ADATA DDR2 667 DIMM-PC5300 CAS 5.0

Will I beable to see a big difference in the speed my system runs?

My CPU is a Pentium D945 Dual core 3.4Ghz 4Mb Cache 2!

Hope someone has some experience they can share with me!

Thanks

 

[lemonadesoda]

WARNING:

You CANNOT run both types of memory at the same time. So if you buy DDR2 you will have to retire the DDR.

***

You will see very little difference in performance between the two memories you indicated, in fact, possibly a small hit with the DDR2 / 667 CAS 5.0.

Rough and ready formula:

Speed increase of DDR2 over DDR = [ DDR2 speed/DDR speed x DDR CAS / DDR2 CAS - 1 ] x 100%

And in your case this is = 667 / 400 x 3.0 / 5.0 -1 = 0%

i.e. no noticable change at all. You are swapping technology, but you aren't changing performance.

(PS. This is not a perfect technical formula, and there are other effects, but it is a rough and ready indicator that works for most "user experiences")

I say stick with your DDR.

 

[bruins004]

I agree.
If you look at the AMD 939 pinset and the AMD AM2 pinset, there are no gains at all over the 939 systems.
Also, please note that there is relatively no seen value from DDR667 over DDR800.
THe only reason people buy DDR800 is bc it can OC better to show some noticeable improvements.

Just my 2 cents worth.

 

[Alcpone]

Thanks for the replies guys, I was aware that I couldnt run the different technologies at different speeds!

I think I may stick with what ive got!

Cheers