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Overclock dual 1.42 MDD... performance gain??

Discussion in 'PowerPC Macs' started by Nova77, Aug 24, 2011.

  1. Guest

    Hi, anyone can tell me what you gain by overclocking a dual 1.42 @ 1.5, and @1.67...?

    Any other tricks to boost performance? (other than hard drive, graphics and RAM upgrade).

  2. macrumors 6502a


    You get more megahertz.

    My dual 1.42 is running at 1.58 at stock volts. It's 100% stable. I think it would hit 1.67 but I haven't bothered to push it any further because I never use it anymore.
  3. macrumors G4

    Lord Blackadder

    A fast, modern HDD can make a substantial difference in performance. New SATA or eSATA setups can move data quite a bit faster than the onboard ATA system.
  4. Guest

    ....... where are the infos, comparison of before and after the overclock... and well anything that answers my question??... please...


    I said, overclocking or other solution than hard drive and ram.
    I can't go much further with RAM and HDD upgrade anyways. I've passed the 100 MB/sec mark, so... you know... Maybe SATA 2 card, but **** those can't boot and costs 3X the price.
  5. macrumors G4

    Lord Blackadder

    You can try overclocking the bus. But that is a very touchy affair, and I'm not sure how well the MDD responds to a system bus overclock.
  6. Guest

    thats a good question... anybody knows if it is possible to overclock the FSB to more than the stock 167mhz?? I know theres a trick for the 133mhz MDDs, but that is NOT the question here...
  7. macrumors 6502

    Exactly what you would expect mathematically. It's linear.

    The difference between my 1.42 and 1.5 with no other changes to system:


    Results 66.64
    System Info
    Xbench Version 1.3
    System Version 10.5.8 (9L31a)
    Physical RAM 2048 MB
    Model PowerMac3,6
    Processor PowerPC G4x2 @ 1.42 GHz
    Version 7455 (Apollo) v3.3
    L1 Cache 32K (instruction), 32K (data)
    L2 Cache 256K @ 1.42 GHz
    L3 Cache 2048K @ 237 MHz
    Bus Frequency 167 MHz
    Video Card ATY,R350
    Drive Type ST3500418AS ST3500418AS

    CPU Test 76.67
    GCD Loop 135.60 7.15 Mops/sec
    Floating Point Basic 49.63 1.18 Gflop/sec
    AltiVec Basic 279.53 11.14 Gflop/sec
    vecLib FFT 83.18 2.74 Gflop/sec
    Floating Point Library 45.27 7.88 Mops/sec
    Thread Test 74.53
    Computation 110.92 2.25 Mops/sec, 4 threads
    Lock Contention 56.12 2.41 Mlocks/sec, 4 threads

    Memory Test 49.94
    System 57.88
    Allocate 219.72 806.90 Kalloc/sec
    Fill 56.66 2754.73 MB/sec
    Copy 33.75 697.10 MB/sec
    Stream 43.92
    Copy 46.78 966.27 MB/sec [altivec]
    Scale 47.49 981.05 MB/sec [altivec]
    Add 43.27 921.66 MB/sec [altivec]
    Triad 39.17 837.89 MB/sec [altivec]

    Quartz Graphics Test 86.61
    Line 73.60 4.90 Klines/sec [50% alpha]
    Rectangle 78.24 23.36 Krects/sec [50% alpha]
    Circle 70.59 5.75 Kcircles/sec [50% alpha]
    Bezier 81.44 2.05 Kbeziers/sec [50% alpha]
    Text 203.25 12.71 Kchars/sec
    OpenGL Graphics Test 76.31
    Spinning Squares 76.31 96.81 frames/sec
    User Interface Test 51.33
    Elements 51.33 235.59 refresh/sec

    Disk Test 69.28
    Sequential 128.44
    Uncached Write 144.58 88.77 MB/sec [4K blocks]
    Uncached Write 142.07 80.39 MB/sec [256K blocks]
    Uncached Read 91.10 26.66 MB/sec [4K blocks]
    Uncached Read 161.03 80.93 MB/sec [256K blocks]
    Random 47.43
    Uncached Write 15.70 1.66 MB/sec [4K blocks]
    Uncached Write 222.19 71.13 MB/sec [256K blocks]
    Uncached Read 101.71 0.72 MB/sec [4K blocks]
    Uncached Read 158.33 29.38 MB/sec [256K blocks]


    Results 71.72
    System Info
    Xbench Version 1.3
    System Version 10.5.8 (9L31a)
    Physical RAM 2048 MB
    Model PowerMac3,6
    Processor PowerPC G4x2 @ 1.50 GHz
    Version 7455 (Apollo) v3.3
    L1 Cache 32K (instruction), 32K (data)
    L2 Cache 256K @ 1.50 GHz
    L3 Cache 2048K @ 250 MHz
    Bus Frequency 167 MHz
    Video Card ATY,R350
    Drive Type ST3500418AS ST3500418AS

    CPU Test 81.35
    GCD Loop 143.74 7.58 Mops/sec
    Floating Point Basic 52.66 1.25 Gflop/sec
    AltiVec Basic 297.59 11.86 Gflop/sec
    vecLib FFT 88.32 2.91 Gflop/sec
    Floating Point Library 47.99 8.36 Mops/sec
    Thread Test 88.62
    Computation 121.92 2.47 Mops/sec, 4 threads
    Lock Contention 69.61 2.99 Mlocks/sec, 4 threads

    Memory Test 51.83
    System 64.44
    Allocate 277.47 1.02 Malloc/sec
    Fill 64.32 3127.43 MB/sec
    Copy 36.49 753.63 MB/sec
    Stream 43.35
    Copy 45.42 938.19 MB/sec [altivec]
    Scale 47.27 976.53 MB/sec [altivec]
    Add 41.99 894.47 MB/sec [altivec]
    Triad 39.54 845.87 MB/sec [altivec]

    Quartz Graphics Test 93.12
    Line 75.04 5.00 Klines/sec [50% alpha]
    Rectangle 83.83 25.03 Krects/sec [50% alpha]
    Circle 80.02 6.52 Kcircles/sec [50% alpha]
    Bezier 88.64 2.24 Kbeziers/sec [50% alpha]
    Text 214.66 13.43 Kchars/sec
    OpenGL Graphics Test 80.02
    Spinning Squares 80.02 101.51 frames/sec
    User Interface Test 58.33
    Elements 58.33 267.70 refresh/sec

    Disk Test 69.69
    Sequential 128.73
    Uncached Write 145.26 89.19 MB/sec [4K blocks]
    Uncached Write 142.69 80.74 MB/sec [256K blocks]
    Uncached Read 90.53 26.49 MB/sec [4K blocks]
    Uncached Read 163.01 81.93 MB/sec [256K blocks]
    Random 47.77
    Uncached Write 15.77 1.67 MB/sec [4K blocks]
    Uncached Write 228.73 73.23 MB/sec [256K blocks]
    Uncached Read 103.94 0.74 MB/sec [4K blocks]
    Uncached Read 157.73 29.27 MB/sec [256K blocks]

    1.58 was also stable for mine, but the temperature jumped a little above my comfort level so I dropped it back down (my comfort level for temperature is much below manufacturer's specs).

    Of course, not all 1.42's are going to be the same. As long as you're comfortable with your soldering skills, though, it doesn't hurt try for something higher and then drop it back down if it doesn't work out. I think 1.5 is pretty much a given for any 1.42. My impression based on what I've read and done (I can't quantify this in any way. People are probably more likely to post about their victories than their failures, so I'm basically pulling this out of my you know what) is that 1.5 is a given, 1.58 works more often than not, and the odds are against you at 1.67 (people seem to have more success with water cooling). If I'm not mistaken, though, at least one user here has gotten 1.67 without water cooling. Maybe 666Sheep?

    I would strongly urge you, Nova77, to consider using CHUD if this is the next step for your MDD. It might make the difference between something you're comfortable with and something that you're not. The cooler they run, the longer they will last.
  8. Guest

    @ThunderSnake thanks a lot, that is the kind of infos I was looking for.
    Now will 666sheep get out of the shadows and share with us his knowledge? lol :p
  9. macrumors 68020


    IMO a gain of only 80-200MHz isn't worth the extra strain it will put on 8 year old CPU's that already run very hot at stock speeds.

    The 7455 is by far the hottest running G4 chip. It will shorten the remaining life of the CPU's.
  10. macrumors 6502

    Heh. I just called him out in another thread, so maybe he'll show up.

    Totally agree. To me, it's not worth it if you're going to be pushing these chips to the limits of their design specification. Keep an eye on those temps. I have another 1.42 daughtercard that I haven't messed with yet that I might try to get 1.58 out of, but not if the temps climb to the high 50's on a regular basis. My 1.5 rarely gets above 50C. The fans never kick into high speed. It's very quiet. Again, CHUD helps a lot.
  11. macrumors G4

    Lord Blackadder

    Overclocking is a fun hobby, but the PowerPC CPUs in Macs don't respond all that well to overclocking (especially when you compare them with x86 CPUs).

    Personally I'd leave the dual 1.42 MDD alone in terms of its CPUs.
  12. macrumors 68020


    I never overclocked my 2 dual MDD's (867 and 1.42) but I did run nap and replaced all the stock fans. Doing lower to mid level taxing of the systems would keep the 867 at 42-43c and 1.42 at 46-48. Because I added an external 120mm on both to help exhaust heat they both never went above maybe 52 even under 100% load for hours.
  13. macrumors 6502

    Me too. Sort of. I added an 80mm exhaust fan internally between the CPU and the case. It's mounted high enough that it helps vent GPU heat too. Great minds think alike!
  14. Guest

    Everybody knows what overclocking does... yep more heat... But this is totally off topic guys, I was asking about performance, not if I should do it or not in your opinion.

    Btw heat is not so bad... my MDD runs AT MOST @ 56 °C in hot summer, and it is not a genuine 1.42 MDD so the CPU fan is less powerful. I have no cooling mods at all. I don't know why everyone seems to have such bad heat issues with MDDs.... Maybe its time for them to replace that old thermal paste??!!

    Just by changing the fan and adding 2 small fans near the CPU (you know, what everybody does just for cooling their non-overclocked MDD), I think it would easily reach 1.5 ghz without major heat issues.

    Oh well, I did continue off track....
    Now, back on topic...!
  15. macrumors 68020


    Yes everyone.. lets all shut up and answer all of Nova questions exactly how he wants.

    You're kind of acting like we work for you or something..
  16. macrumors 6502

    I get that you understand the risks, but lots of people read these things, so I think it's appropriate to include some cautions. The only opinion that I've offered you specifically is that I think you should run CHUD. :)
  17. Nova77, Aug 24, 2011
    Last edited: Aug 24, 2011


    Hmmm.... no?... Is that your sense of humor zen.state? :p

    Don't know if I sound like a boss or something but thats not the goal... XD

    It was just a reminder of what this thread is about :


    It's not about heat. Thats it. Reply the way you want, but if you want to start a new topic, why not start another thread...

    So this is the best place to post benchmarks of before/after overclocking, just like Thundersnake did.
  18. macrumors 6502a


    I have nothing to lose beings I don't use that MDD anymore, so this weekend I'll try to push it as far as it'll go. My current over clock is on stock cooling and temps are the same as they were with stock speed.
  19. Guest

    Nice! Don't forget to run some benchmarks before the overclock
  20. macrumors 68040


    Exactly, esp. in synthetic benchmarks.

    TS: You did ask about WC in another thread: no, mine is aircooled (still... I've stuck on case surgery stage + looking for waterblock for 7800GS). But it's way too loud (2x Delta 1212SHE, I got rid of optical drive) :( I had to raise CV a lot from stock value and without massive fans CPU and L3 chips are overheating very fast. WC is on it's way :)

    Let's see what bizzle will be able to reach. Each daughtercard may have a different OC potential, but I'm 99% sure that 1.67 is max for 7455 w L3. Question is: with what Core Voltage ;)
  21. Guest

    Can you post some benchmarks of your 1.67 MDD? Or other infos.... I want to know if its worth the overclock.
  22. macrumors 68040


  23. macrumors 6502

    Had my old 1.42 overclocked to 1.58 and it died after a year. Not sure if it was worth it or not.
  24. Guest

    fried CPU or another problem?...
    What about you other overclockers? For how long have you been using your o'clocked CPUs?
  25. macrumors 6502

    Are you certain that it was the CPU? What temperature did it run? At idle? At full load? Were you running CHUD? Did you apply fresh thermal compound? (Please don't be insulted by that last question, but I'm surprised by how many people do not know to do this. I've found that it's worth asking even with folks savvy enough to do their own overclocking.) Anything additional that you have to offer could be helpful.

    Only about 18 months on my MDD, but I've had an OC'd DA module running fine for about seven years or so. As long as they run cool (of course, "cool" is a relative term when talking MDDs), they should be fine.

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