Athlon 64 Memory: Rewriting the Rules

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• Wesley Fink - Friday, October 1, 2004 - link

  #22, #25 and others -
  
  The 465W power supply that was not up to the job had the following specifications:
  
  +3.3V - 38A
  +5V - 44A
  +12V - 20A
  -5V - 2A
  -12V - 1A
  +5Vsb - 2.2A
  
  I would never have had any reason to suspect issues with this expensive major brand PS based on those specs, but in fact it turned out to be the limiting factor in overclocking the memory.
  
  This issue requires more investigation as there are many possible reasons for my experience, but I felt an obligation to let readers know what we found in our testing. However, it is not fair to name brands without much more evidence.

• Blappo - Friday, October 1, 2004 - link

  Hopefully the value memory roundup will also contain some generic memory as well. Knowing which premium memory is the faster is good, but I want to know how much of a difference memory makes on system performance. I don't want to spend 50% more for only 5% more performance. That money could be better spent somewhere else.
  
  I'm glad that AnandTech did this article since everywhere else they only benchmark memory on Intel systems.

• Blappo - Friday, October 1, 2004 - link

  PrinceXizor - I agree completely. However, with higher wattage PSU most of the extra power comes on the 12V rail. I think that is why nVidia is recommending "monster" PSU for their high-end graphics cards because it is easier to tell people to buy a 480W PSU rather than a PSU that can deliver 22A (or whatever) on the 12V rail.

• Spearhawk - Friday, October 1, 2004 - link

  15: 20A? You're kiding right? My oven are at 20A.

• decptt - Friday, October 1, 2004 - link

  My Ballistix performance
  =============================================
  "Dec" copyright since Duron600@1000
  =============================================
  Athlon64 Mobile 3200+ Rev.SH7-CG
  AMA3200BEX5AR-ClawHammer L2:1MB
  10x250 vid:1.5v+113%(~1.70v)
  Idle@36C Load(Prime95)@43C
  [10x255 worked @~1.97v Loaded(Prime95)@55C]
  
  Crucial Ballistix PC3200 512MBx2 vcore:2.70v
  Ratio = 1:1 ; TCl:2.5-Trcd:3-Tras:5-Trp:3 1T
  ATI AIW 9600XT 128MB BUS:75 vcore:1.6v
  DFI Lanparty UT NF3-250 Rev.A00 Bios.9/14(Beta)
  LDT/FSB@ 4X
  Thermalright XP-90 +Panaflo-H1B-92(FBA09A12H)
  Seagate ST3120026A
  DVD model DD0401
  TruePower480
  
  Scroll(Tested@2.50GHz on Sep 30, 2004)
  SiSoft2004.10.9.133
  CPU::ALU 11513 FPU 3954 iSSE2 5156
  Media:: Int 23895 Float 2562
  Ram:: Int 3780 MB/s Float 3779 MB/s
  3DMark03V3.4.0--1751 :(
  PCMark2004v1.2.0--3688
  Super PI 1M 35s
  Super PI 2M 1M23s
  =============================================

• quanta - Friday, October 1, 2004 - link

  Speaking of robust 12V rails, Enermax seems to be the only one make power supplies that can provide more +12V juice than most enthusists ever need, even for models without splitting +12V lines.

• AlphaFox - Friday, October 1, 2004 - link

  where did the power supply talk come from??

• PrinceXizor - Friday, October 1, 2004 - link

  Just a further comment on the PSU "recommendation". I really think that the major tech sites are doing a disservice to the community when they keep recommending higher and higher total wattage PSU's. That is NOT the issue! As has already been pointed out, the key component is to analyze what voltage rail is is not providing enough juice. Just as clock speed is a poor indicator of processor performance, total wattage is a poor indicator of PSU performance. Considering that a major computer rig will rarely if EVER draw more than 250W of actual power, the key metrics for a PSU are the actual amperages on the various rails, particularly the robustness of the 12V rails. (Some newer PSU's are providing dual 12V rails for just this reason). So, does an enthusiast overclocking their rig need a 500 Watt "monster" or do they need a robust 12V line and tight voltage variance on those lines (as you drive stuff out of spec, the transients in those lines become more critical).
  
  I guess the point of my long-winded post is this...tossing off a "recommendation" like was done in this article (well-intentioned I'm sure) without addressing the actual issues involved seems to me to be habit that should be avoided.
  
  P-X

• rjm55 - Friday, October 1, 2004 - link

  As you pointed out, you can't do the kind of tests you did here with an Intel rig with a locked multiplier. It was good to see all the different memory speeds at the same CPU speed, which proved once and for all that higher memory speeds DO improve performance - even with slower timings at higher speed. Makes my mouth water thinking about how good DDR550 at 2.5-2-2 would be.
  
  I realize the performance differences weren't huge with just the memory overclocked, but most people will overclock the CPU AND the RAM and that will make a huge combined difference in performance. Tweaking is about squeezing the most from your gear, and you CAN get more out of memory at higher speeds.

• eetnoyer - Friday, October 1, 2004 - link

  Try newegg.com
  
  http://www.newegg.com/app/viewProductDesc.asp?desc...