Dual Channel DDR basics...

Discussion in 'Links' started by syntax_error, Feb 10, 2003.

  1. CVND

    CVND Master Guru

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    ok thx a lot
     
  2. BillZad

    BillZad Guest

    :cool: Ok Let's fast foward 1 year to Jan 2004, the day is coming
    for the NEW standard ---- 4 channel mother boards, all mother boards now r 2 channel based, including the HOT Asus P4C800E Deluxe with Intel 875p chipset @ 6.4gig bandwidth with DDR 400 memory.........Intel's last great mother board that supported RDRAM Asus P4T533/850E chipset 32 bit RIMM 4200 @ 1066=4.2 gig bandwidth
    is still a fast setup......... Here's the new info--- Samsung's new RIMM 4800@1200=9.6gig bandwidth RDRAM memory, but Intel does not support the new RDRAM with their current chipsets.......
    So SIS has their new chipset for the new RDRAM called R659 ...
    this is a 4 channel based chipset instead of the current 2 channel
    based chipsets from all chipset company's at this time.......Asus is testing a new SIS chipset mother board ---4 channel P4S13G with
    the new RIMM 4800 RDRAM memory........YEAHHHH BABYYYYY !!!
    So hold onto that CASH burning a hole in your pocket's, and wait
    for the new GOODIES coming soon !!!!! Check out Samsung's & SIS's web sites for the new info..........:D
     
  3. -=WODS=-

    -=WODS=- Guest

    How can you see if you are running Dual Channel?
    And does my Asus P4P800e Gold support it?

    thx
     
  4. BLyarx

    BLyarx Ancient Guru

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    Download SiSoft SANDRA and compare your memory bandwith results with sandra's .. Your board should support dual channel it's an p4p800...
     

  5. -=MLF=-420

    -=MLF=-420 Guest

    I have a question.

    I just got a Gigabyte GA-8IPE1000-G and its a 800fsb/Dual DDR 400 board. I also have 2x512 of pc3200 400 that I picked up too.

    Now I still have my P4 2ghz and my memory only runs at 333mhz. Do I need to have a 2.6ghz or higher to use my 400mhz ram?
     
  6. Fahad145

    Fahad145 Guest

    I was just wondering, since the arrival of DDR2 is just few months away, and the socket 775 is also few months away, should i wait for them? Also, when is Q2 '04?
     
  7. st0nez

    st0nez Master Guru

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    -=MLF=-420 - I have the same motherboard well the pro2 model anyways.
    they only support ddr400 for the c class processors urs would be a a or b
     
  8. xankazo

    xankazo Ancient Guru

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    I have a 865pe neo-2 mobo from MSI, running along with 2 sticks of 512mb (corsair value select) rams. In the POST, it says dual channel liner mode (don't know what it means), but I only get 3500 in memory bandwith test in sis-sandra 2004.

    isn't it supposed to be any higher? is there anything wrong? someone to enlighten me please.
     
  9. JohnMaclane

    JohnMaclane Ancient Guru

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    thanks thats a real good post. but if you have dual channel does it mean that your computer works better in over clocking or it doesnt make a diffrence cause i was thinking of getting the asus P4P800-E Deluxe but my friend said that it wont be good for over clocking
     
  10. bigpawlu

    bigpawlu Guest

    vince told u joe?

    casue i said that board rocks:D
     

  11. dzutrinh

    dzutrinh Master Guru

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    upgrade to a p4c 2.4ghz or p4c 2.8ghz or any higher p4 in C class.
     
  12. xankazo

    xankazo Ancient Guru

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    that's right, and make sure your new CPU is 800mhz FSB.
     
  13. Liranan

    Liranan Ancient Guru

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    Well guys let me tell you one thing: I have found that Dual Channel makes a lot of difference when it comes to system performance! I have experimented with PC2100/2700 and 3200 and apart from having found that nothing can beat my 4000 the real boost came from Dual Channel.

    There is a very simple way to calculate it: take the theoretical output of the fsb (in the case of 400 MHz that's 3.2GB/s) and devide that by 3. That will give you the average and actual output of the system. In my case it's 960*8=7680. 7680/3=~2500. Then we must take the inefficiency of the norhbridge and the loss of bandwidth into concideration which (unfortunately) occurs along the way and we end up with (if lucky) 70 to 80% of the total bandwidth. I am, thus, left with ~2.3GB/s. Compared to ~1GB/s in Single Channel.

    For all of you who are now going to jump out of your skins and scream that it's more than that I have two things to say:
    1. prove that it's any different
    2. unfortunately for you this simple formula is the way it works

    There are several programs which determine the bandwidth and one of these programs I have found pretty handy is Sandra. Eventhough Sandra calculates what the program thinks is the 'effective' output the programs truely calculates the bandwidth once all of the CPU's optimizations have been disabled (eg. MMX, SSE, SSE2, etc.).

    In games and many applications I have found that Dual Channel really does make a difference and that Single Channel, no matter how fast or good, just can't beat Dual.
     
  14. teqguy

    teqguy Guest

    Memory bandwidth is actually very hard to saturate... so the additional bandwidth in real world use(gaming or otherwise) is insignificant. This is mostly attributed to the lack of internal hard drive bandwidth.

    Currently, the only way to reap the rewards from dual channel is to run a ramdrive and either execute your application from there or encode/render to and from the ramdrive.

    However, the read/write consistency does increase due to bit width and interleaving.
     
  15. G L

    G L Don Juan

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    This is an interesting theory, but the problem is that programs do seem to benefit slightly from dual-channel, and this can expecially be seen with the Athlon 64s. AMD reckons dual-channel to be worth about 200 MHz, so that the 754 3000+ is 2.0 GHz 512k and the 939 3000+ is 1.8 GHz 512k. Furthermore, this advantage seems to justified by most benchmarks, except those that are almost totally insensitive to memory performance.
     

  16. teqguy

    teqguy Guest

    Benchmarks don't operate like normal applications, though. They have fixed functions.

    There's a certain point where dual channel doesn't help whatsoever... which is typically if you have DDR memory clocked at 333Mhz or faster.
     
  17. G L

    G L Don Juan

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    I'm talking about gaming benchmarks, mostly, between 743 and 939 Athlon 64s... I think the difference is something like +3%... not huge, but its definately there.
     
  18. Liranan

    Liranan Ancient Guru

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    I just reread that post of mine and it sounds so stupid, like a spoilt little brat who wants his own way... sorry guys.

    Anyway it seems that it's just the P4 that needs the mem bandwidth as AMD has shown that PC3200 in single channel can do miracles an Intel has had to resort to DDRII and 1066MHz fsb to best the AMD64's. Thus account must be taken of architecture and technology rather than just pure numbers because the AMD's integrated memory controller still bests my dual channel running at 960MHz with the greatest ease and leaves me standing.

    However memory bandwidth doesn't really make 'that' much of a difference to games but you must understand that in a way teqguy is right because benchmarks only test certain criteria and scores rarely relate to real-life performance, if they did I wouldn't be running FarCry at low settings because of the scores I get is 2003 and 2005. But mem banwidth still does make a difference and it's still relevant to the system regardless of how little it is, if it didn't then we would all still be using PC66 let alone PC133 or even EDO.
     
  19. teqguy

    teqguy Guest

    Well, I wouldn't go that far.

    There's a certain limit in which the memory bandwidth is still of any relevancy in terms of performance.

    PC133 did have a problem attaining the neccessary bandwidth for the Pentium III and Athlon, which is why RDRAM should've been pushed earlier.

    However, DDR333 running in dual channel mode is more than enough memory bandwidth for most tasks. Any other benefits you see from having faster memory is probably due to the frequency, rather than the bandwidth.
     
    Last edited by a moderator: Mar 22, 2005
  20. G L

    G L Don Juan

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    Tests between similarly clocked 754 and 939 pin Athlon 64s show a small performance gain, which could only be atributed to dual-channel since they're both running PC3200. Now I suppose this could somehow result from something other then just doubled bandwidth, but the reason for the benefit is difficult to establish and isn't terribly important.
     

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