The answer of the age-old question: 4x512mb or 2x1024mb?

Discussion in 'Memory' started by robberbaron, Jun 21, 2005.

  1. robberbaron

    robberbaron [H]ardness Supreme

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    Hello fellow forum goers. I have noticed an increase in threads asking which would be better of these two choices on an Athlon 64/Sempron:

    • 4x512mb
    • 2x1024mb ram

    First, I will clear up some misconceptions of the "limitations" of the A64 memory controller.
    I will reference this thread often.

    You can see in that thread that the only benchmarks affected by 1T/2T are gaming benches and memory specific benches (surprise surprise.) You can also see the change in memory speed has a little role in CPU intensive applications like Cinebench rendering and multimedia applications. So that in mind, let's explore our options when forced to run 2T.

    In this case, to attain 2 gigs, we would almost certainly have 4x512mb of ram. Your memory controller will then be saturated. On anything pre-Revision E (cores before the Venice, San Diego, Manchester, Toledo, Lancaster, Newark, and the "BO" Palermo cores), this would mean a certain memory speed and latency hit, and it would be very noticeable. In this case, 2x1024 would be best, since you could still get 1024 sticks with reasonable timings (2.5-3-2 or so) and use a memory divider to OC the cpu. To push this point, I will show you old robberbaron's list of A64 priorities:

    1. CPU Speed!
    2. CPU Speed again!
    3. Memory timings
    4. Memory speed > 200MHz/DDR400

    You will find the most performance of all when you are running at your maximum CPU speed, regardless of memory speed and timings as long as they dont fall too far below 3-3-3 and 200MHz. However, for gaming, memory latencies are a little more important.
    Let's review that counterstrike bench.

    In the thread that I referenced earlier, you see a drop of about 13-15 FPS across the board when running at a lower memory speed. 1T and 2T have very little difference.

    Here is some "realworld" gameplay data for CS:Source.

    1280x1024, all high, 4xAA 8xAF
    2.5GHz with 192MHz memory
    1T: 92FPS
    2T: 90FPS

    So, when playing, the more you put a load on your snazzy video card, the less you feel the hit. This is to be expected, so don't fret too much.

    However, let's see what framerate I'd be getting with a full 10x250MHz 1:1
    1T: 109 FPS
    2T: 108 FPS

    So there you have it. Memory speed can get you more performance in games. So it comes down to what you'll be doing with the system, at this point.

    For gaming, you'll probably want to go with 4x512 of memory that is known to hit good speeds (240MHz or so) and keep decent 2.5-2-2 or 2-2-2 timings. As you can see, you don't have to worry about the 2T performance hit because the memory speed will more than compensate that. Crucial Ballistix fits this bill and is much cheaper than the alternative of GSkill TCCD. Or, you could try your luck with 2 gigs of TwinMOS SP or Mushkin Redline.

    For basically all else, it would probably be quite a bit cheaper to get 2x1024mb sticks. Some, such as Crucial or Patriot, can have very tight timings at between 200 and 220mhz. So those would be a good choice. Another advantage of 2x1024 is that it leaves some slots empty for future expansion. I hope that you are now a more informed forum in this regard.

    To those wondering why the A64 memory controller does this, here is the (highly simplified) answer. When it tries to access 4 sticks of double sided ram, it simply cannot run at a quick enough pace. So it turns down to 2T in order to "ease" the "work load." However, this applies to doubled-banked dimms. There are, in fact, single sided 512MB sticks! Yes, there are!

    http://www.newegg.com/Product/Product.asp?Item=N82E16820146541

    That is singled sided. Note the .8T at the end. It means that there are 8 chips total. The memory chips on this dimm are normally used in 1 gig sticks, so think of this as a one gig stick with one side blank. I have no experience with this stick, but I have no reason to believe that on RevE, it can run at full speed with 1T. On pre-RevE, it will definately run at full speed with 2T.
     
  2. [Tripod]MajorPayne

    [Tripod]MajorPayne [H]ardness Supreme

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    Woot! I have an Intel system, but I'm assuming that this sort of carries over across platforms, right? I've got a thread going on the same subject. I'll go 4x512 and see what's up, then post it here if I get them. Thanks for the info, very informative post. :)
     
  3. robberbaron

    robberbaron [H]ardness Supreme

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    Bandwidth is key on intel systems. Unfortunately, I only have one with RDRAM so I can't do a whole lot of tweaking. Also, intel systems dont turn on 2T with 4x512mb.
     
  4. Autochthon

    Autochthon Limp Gawd

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    GJ! you read my mind, was going to ask you to get down to the nitty gritty on this issue.

    why don't you incorporate the single side double side issue as that is related and can be confusing.
     
  5. robberbaron

    robberbaron [H]ardness Supreme

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    Gosharoo, I actually forgot about that. Thanks for the reminded :)

    added.
     
  6. [Tripod]MajorPayne

    [Tripod]MajorPayne [H]ardness Supreme

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    They don't turn on 2T? So you're saying I'll run 1T with 4x512? I hope I read that right...I'm having a REALLY slow mental day today, sorry! :cool:
     
  7. robberbaron

    robberbaron [H]ardness Supreme

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    Yeah, the Intel memory controller can handle 4 double sided dimms without switching to 2T. You'll have no issues running 4x512 on an Intel system.
     
  8. jhego

    jhego [H]ard|Gawd

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    damn A64 architecture :mad:
     
  9. (cf)Eclipse

    (cf)Eclipse Freelance Overclocker

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    remember that 1T/2T has much less of an impact on p4's
     
  10. [Tripod]MajorPayne

    [Tripod]MajorPayne [H]ardness Supreme

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    Hopefully so. I just bought an extra GB of the stuff I already have from newegg, so as soon as it gets here, I'll post up info on timings, overclocks, and BF2 performance as soon as I can. I'm guinea-pigging it for you guys on Intel systems. :D Oh, and Eclipse and robberbaron, if you perhaps SENT me an AMD system to have...I mean, play with, I'd do it for an AMD platform, too. As long as it's a high-end system so we get a good representation of the capabilites. I don't ask much. Just an X2 4400+, 2GB of RAM, a DFI SLI board and 2 6800 GT's. That's not too hard, now is it? :D
     
  11. CCUABIDExORxDIE

    CCUABIDExORxDIE 2[H]4U

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    would you rather have 90+% eff, or 70-80% bandwidth eff? thats why i love the a64 architecture.
     
  12. SuddenDemise

    SuddenDemise Limp Gawd

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    So basically 4x512 is best, all though it drops down to 2T...But the hit of 2T isn't very significant...did I understand that right?
     
  13. (cf)Eclipse

    (cf)Eclipse Freelance Overclocker

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    yes and no.
    it will drop to 2T, which is a decent latency, and in some cases, bandwidth hit.
    the question i've asked before, what's better, 4x512mb at 2-2-2, with 2T or 2x1gb at 3-3-3, 1T, both at 250mhz?

    i think this is something i will have to test, but with 1x512mn and 2x256mb, as i only have 3 ram slots to work with, and my ram that can do 250mhz at 2-2-2 is.. smallish :p
     
  14. Chris Lakies

    Chris Lakies Limp Gawd

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    Get the 2x1 gig of ram, because not running in dual channel slows your system down. If you run 4x512mb, not only do you have to run the ram at 2T but you cant overclock much (if any) and you have to run single channel.

    For instance my Aquamark score 2x512mb = 83,000

    Running with 2x512mb & 2x256mb = 75,000

    But the extra ram does help alot in BF2!

    Thats why I'm getting 2x1gig of Patriot PEP3200LL!
     
  15. Amd For Ever

    Amd For Ever n00b

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    I just saw a review on Anandtech saying that the new amd cores (revision E) do not use 1T with 4 dimm slots used. http://www.anandtech.com/mb/showdoc.aspx?i=2457&p=6

    "Unfortunately the long-rumored 1T Command Rate with Rev. E AMD processors appears to have been just a rumor. We could not run 4 matched dimms at 1T in a motherboard with Rev. E/x2 support. Four dimms still required a 2T Command Rate."

    Now which is it? You can use 4 dimm slots or just 2 and use 1T? How do you tell if your memory timings are 1T or 2T?
     
  16. Amd For Ever

    Amd For Ever n00b

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    Do 1 GB sticks usually have lower memory timings than smaller amounts?
    Would 2 X 1GB regular sticks be faster or better than 2 X 512mb top of the line sticks?
    Does using all 4 dimm slots in dual channel give you a 256 bit interface or would it be the same bandwidth or speed as just using 2 dimm slots of the same type?
     
  17. Amd For Ever

    Amd For Ever n00b

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    You can't use all 4 dimms in dual channel?? It reverts you to single channel?
     
  18. (cf)Eclipse

    (cf)Eclipse Freelance Overclocker

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    oh wow..


    4 doubled sided dimms for s939 means 200mhz & 2T for revE, 166mhz & 2T for everything else

    1gb sticks typically have higher timings than their less dense counterparts, as the high density ram chips are. somewhat difficult to make.

    using all 4 dimms will still be dual channel... just with 2T command rate

    you can tell if you're using 1T or 2T with a good program that reports timings and stuff. i personally like everest:
    http://www.lavalys.com/products/overview.php?pid=1&lang=en
     
  19. Amd For Ever

    Amd For Ever n00b

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    So for gaming I should use 2 X 1 gb sticks so that it will run at 200 mhz 1T instead of 4 x 512 mb? Would the higher timings on the 1 gb sticks at 1T be worse or better than 2T on the 512s with better timings? Seeing as 1T and 2T doesn't seem to matter much except for games occording to that sticky, but timings don't seem like they matter much either unless you move from 2-2-2-8 to 4-4-4-12. Only drastic changes seem to matter for timings so I don't see why everyone is like I love heart, heart 1.5-2-2-2 and will pay my inheritence over good 3-3-3-8s or lower.
     
  20. Chris Lakies

    Chris Lakies Limp Gawd

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    Yes 2x1g sticks would be the best choice for gaming.

    I ordered 2x1 gig of Patriot PEP1G3200LL which is rated at DDR400 and 2-3-2-5 @ 2.6volts from new egg. They were about $113.00 each.
     
  21. H8Mondays

    H8Mondays [H]Lite

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    (cf)Eclipse,

    Maybe I'm reading this wrong but I interpret what has been stated as basically this:
    1. Using 4x512 with great timings does NOT suffer a "significant" hit to performance when dropped to 2T.
    2. Using 2x1024 with good timings does NOT suffer a "significant" hit in performance and remains in the "coveted" 1T area ;)

    So in essence, either solution will get you what you want, 2 gigs of good performance. If you put these two setups side by side you are not going to "see" a big difference and if you go the 2 route you have room for more RAM later(but unless a future chip revision comes along correcting the memory controller, once you fill all four slot you will drop to 2T at which point with looser timings you should see a big difference). Seems like we are beginning to move past the 1Gig sweet spot so we should see some 1 Gig sticks with slightly better timings, but I'm thinking those will be few and far between as things will begin shifting to DDR2? Am I close? My poor old brain and eyes will not notice the difference between the two...I'm just not THAT talented. :eek: 2x1024 for me. Socket M, anyone?
     
  22. (cf)Eclipse

    (cf)Eclipse Freelance Overclocker

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    just about dead on :D

    and yeah, since ddr2 is on it's way, i don't think much effort will be put into making new quality ddr :(
     
  23. Amd For Ever

    Amd For Ever n00b

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    How good are those patriot sticks at overclocking compared to the crucial ballistixs or ocz performance? Those are really cheap compared to ballistix and isn't the ballistixs the cheapeast high quality memory out there?
     
  24. Chris Lakies

    Chris Lakies Limp Gawd

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    Not sure yet...they will be here tomorrow. :D

    Yes Crucial Ballistix is alot more because they are DDR500 PC4000 which would be awsome if you have alot of money to spend!
     
  25. n64man120

    n64man120 2[H]4U

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    Well after thread-jacking probably a good 10 threads in my quest for an answer... I went with 2x1024... so I suggest you do the same ;)
     
  26. Chris Lakies

    Chris Lakies Limp Gawd

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    I was suprised. I put in my 2x1gig sticks last night and should have been able to run Battlefield 2 at all high settings without any jerky frame rates......boy was I wrong.

    Even running 2x512 and 2x256 for a total of 1.5gigs (4 dimms filled) was smother than 2x1 gig sticks.

    So I ended up using 3 gig total..... my Corsair 2x512 sticks with my Patriot 2x1 gig sticks (4dimms filled) which allowed me to run all high settings with 8x AA and 16xAF @ 1280x960 res.

    Running 2.6 gig on my 3000+ Venice with 140DDR divider (200mhz 2-3-2-5 mem @ 2T). Ran Prime for 6.5 hours no errors.
     
  27. (cf)Eclipse

    (cf)Eclipse Freelance Overclocker

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    i don't want to be mean, but are you sure it was in the right slots for dual channel?

    also, sig is 10 lines max here, sorry :p
     
  28. Chris Lakies

    Chris Lakies Limp Gawd

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    Yep I tried both 1&3 slots and 2&4 slots. Slots 1&3 seemed to work best (more stable). Oh I have the 5/10 bios. I tried alot of different routes. I fixted my SIG.
     
  29. n64man120

    n64man120 2[H]4U

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    I think slots 2 and 4 are the reccomended ones
     
  30. Chris Lakies

    Chris Lakies Limp Gawd

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    Thats what they recomend in the manual.....I assume for the Bios that ships in the board. I have a newer bios that allows either or. Like I said I tried them in both slots and it seemed the best to be 1 and 3. I know with the orriginal bios (I believe was 3/10) it wouldn't even post if you tried using 1 and 3.
     
  31. (cf)Eclipse

    (cf)Eclipse Freelance Overclocker

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    depends on the ram. i forget which for which, but high voltage ram likes one set and low voltage ram likes the other set.

    i think it's 1+3 for low voltage and 2+4 for high voltage, but i'm not certain
     
  32. yogiB

    yogiB Limp Gawd

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    Do I understand from these posts that for gaming on a P4 it doesn't matter whether 4x512 or 2x1024 are used? That both configurations offer equal performance?
    Please clarify as I am new to this whole memory thing.

    Thanks.
     
  33. CCUABIDExORxDIE

    CCUABIDExORxDIE 2[H]4U

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    4x512mb wont give any more or less performance then 2x1024mb on a p4, because p4's need all the bandwidth they can get, so whatever clocks the highest will be the choice, so probably going with 4x512mb is what you wanna do.
     
  34. fallguy

    fallguy 2[H]4U

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    I wonder this too. Despite the topics title, it doesnt give me a sure answer.

    Im at Cas2 2-2-61T@250FSB 1:1 right now. I just ordered two more 512 sticks. I know Im going to have to go down to 2T, but I can keep my Cas2 2-2-6.

    I wish they would hurry up and make Cas2 2-2-6-1T, 1gig sticks.
     
  35. (cf)Eclipse

    (cf)Eclipse Freelance Overclocker

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    they do, indirectly. baron's 1gb ballistix does 2-2-2 up to 215mhz
     
  36. robberbaron

    robberbaron [H]ardness Supreme

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    Here's a config I used for a while

    http://valid.x86-secret.com/show_oc.php?id=26510

    Value VX and 1 gig crucial ballistix ran in tandem.

    This is stable with my Ballistix 1 gigs
    http://valid.x86-secret.com/show_oc.php?id=25921


    You guys just don't know where to look.
     
  37. fallguy

    fallguy 2[H]4U

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    Thats not near high enough for me. :/
     
  38. robberbaron

    robberbaron [H]ardness Supreme

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    What speeds do you want and with what CPU? For gaming, DDR500 with 1.5-2-2 beats DDR540 3-3-3 by about 2FPS (2000 points in Aquamark.) Since it's hard enough for 512 sticks to hit speeds like CH5 and BH5, 1 gig sticks in DDR1 form that do that will probably never exist.
     
  39. fallguy

    fallguy 2[H]4U

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    Im at 11x250 at the speeds I said earlier, on this 3700+. for 2750Mhz. I dont want to lose any speed. I have two more sticks of 512 Redline PC4000 on the way now, should be here Tues. I know Ill have to drop to 2T, but Im assuming 2-2-2-6-2T wil be faster than any two single 1gig sticks with high latency? I dont know of any that can do anywhere close to that, with 1T at a 250FSB.
     
  40. robberbaron

    robberbaron [H]ardness Supreme

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    Eclipse proved that the 1 gig sticks will beat out 2T with 2-2-2. Crucal Ballistix are the best for latency at high densities, beating out 4x512 just because 2T tends to be more severe than going from 2-2-2 to 3-3-3.