ATI X1900 XT Underclocked

Discussion in 'Mac Pro' started by snaf, Oct 1, 2006.

  1. snaf macrumors newbie

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    Sep 16, 2006
    #1
    hey guys/gals my mac pro is going to be here tuesday ive just read a thread here http://www.barefeats.com/quick.html stating ==>
    September 22nd, 2006 -- Radeon X1900 XT is "detuned"! Though the Radeon X1900 XT "whups" the GeForce 7300 GT, we were surprised to find out that Apple "detuned" the X1900 XT to run at 600 core clock speed and 650 memory clock speed (confirmed by Graphiccelerator). In the Windows PC world, a Radeon X1900 XT typically runs at 625MHz core clock speed and 725MHz memory clock speed. And it does NOT dynamically "up-clock" when you run OpenGL 3D games as in the case of the MacBook Pro 17". (Verified that, too.)

    But there is some good news. You can use Graphiccelerator 1.3.2 to change the ROM code so it runs at "normal" speeds or even better. (The memory clock is rated up to 900MHz.) For example, one user has his X1900 XT running at 650MHz core clock and 775MHz memory clock speed -- which turns it into an XTX. Of course, that may cause the X1900's fan to run more often.

    We have to warn you that overclocking your X1900 XT can potentially "hurt" it or "kill" it. As for dealing with a noisy fan, one of our readers replaced his heatsink/fan assembly with the ARCTIC COOLING Accelero X2 selling for $22 at NewEgg

    so i was thinking about setting the vid card to default clock rate or maybe overclocking it using a product from thermaltake ==> http://www.thermaltakeusa.com/product/Liquid/All-In-One/cl-w0052/cl-w0052.asp
    maybe there are other ideas about this or some helpfull product links/Info or your experience:)
     
  2. Benjamindaines macrumors 68030

    Benjamindaines

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    #2
    I would be pissed if I got a desktop graphics card that was under clocked. I can understand it in a notebook but there's no reason for it in a desktop.
     
  3. zwida macrumors 6502a

    zwida

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    #3
    Apple may have been trying to keep the noise to a minimum. Wouldn't surprise me.
     
  4. lowfi macrumors newbie

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    #4
    I believe ATI always underclocks their EFI cards.....

    Program isnt working for me btw.
     
  5. Silentwave macrumors 68000

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    #5
    Probably because the X1900XT's fan is too loud.

    The 1950 wasn't much of an upgrade performancewise, but its pretty dern quiet!

    Apple, get the 1950 already!
     
  6. Benjamindaines macrumors 68030

    Benjamindaines

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    #6
    Dumbest reason ever.
     
  7. Origin macrumors regular

    Origin

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    #7
    "IF this is clearly true" ... it's bit strange because the 3DMark scores give mainly the same performance of the X1900 XT "Mac Edition" and a stock PC X1900 XT ...
     
  8. NATO macrumors 68000

    NATO

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    #8
    Does anyone know if ATIccelerator is compatible with the X1900?
     
  9. Sun Baked macrumors G5

    Sun Baked

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    #9
    Not really, there is a long history of people complaining about the sound of their Macs.


    The PowerMac G4 HooverMac, the PowerMac G5, the MacBooks, etc.

    So downclocking a card to improve the customers experience, is something that they would likely do.
     
  10. snaf thread starter macrumors newbie

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    Sep 16, 2006
    #10
    ya i just got my info from barefoots page but the underclocking by apple is nothing new but i also didnt think they would do it in a desktop model but who knows & the ATIccelerator II/Graphiccelerator versions that are mentioned at barefoots are not posted at the developers site but barefoot does bring up a great question if it is true and some hope for maybe squeezing a bit more Bang for $$$ value out of the the vid upgrade i ordered from apple (maybe soon the thermaltake vga liquid cooling[2 birds w/1 stone=sound+performance])



    lets crack those MAC Heads together and spark and idea lol :)
     
  11. Benjamindaines macrumors 68030

    Benjamindaines

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    #11
    The MacPro is a pro machine, Apple should sacrifice a little bit of quietness to get the performance. I had a "HooverMac" and it wasn't any worse than a PC.
     
  12. br0adband macrumors 6502a

    br0adband

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    #12
    Interesting news. I'm about to order a MacPro this week, my first brand new computer in my entire life, so it's a big deal for me to finally get a monster that's beautiful, quiet, and upgradeable.

    But this issue with the ATI card being underclocked - and I understand why considering the crap Apple did/is doing with the FB-DIMMs in terms of the heatsinks and requirements - is not going to sway me from the purchase. I've been waiting for a machine like this come along, and that 21GB/s of memory bandwidth... yeah, I waited long enough. :D

    I also understand the logic behind the heat decisions which affect the entire case and operating temps obviously, as designing a system like this requires all the variables to come into play.

    If the FB-DIMMs aren't properly sinked, then that raises the temp in the case, raises the temp of air hitting the sinks on the Xeons, which generates more heat that rises (even with the nice cooling and fans) and then feeds the air around the video card which in turn just runs hotter too.

    The fans come on more often, and the vicious cycle is difficult to break when it starts save for a reboot or complete shutdown or just dead stop idle for a while.

    So for me it's not a big deal. If possible, I'll clock the ATI back up to "stock speeds" at least for the true PC counterparts and see how things go. I don't expect a totally silent PC since it's got moving parts, but I can deal with a little bit of noise.

    Thanks for the info...
    bb

    ps
    Just putting in a request: if anyone out there is capable, can you run some benchmarks with before and after results if you are planning to do the "re-clocking" back to the normal PC counterpart speeds (625/725)? I'd be really interested in seeing those since I won't get my MacPro till probably well past the 14th of October - hopefully faster, of course.

    But seeing exactly how the card does at what should be the "normal" speeds, and perhaps even a bit higher if you're willing to overclock for some testing then return it back down to normal clocks... thanks in advance, I'm sure a lot of people would be very interested in the results of this kind of testing.
     
  13. Mac-Addict macrumors 65816

    Mac-Addict

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    #13
    I hope they won't do this on my soon to be iMac's GT7600, I hope they only do it with ATI cards :p
     
  14. mmmcheese macrumors 6502a

    mmmcheese

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    Feb 17, 2006
    #14
    Actually, it's ATI, not Apple that "underclocks" them...they don't make as many boards for macs as they do for pcs, so they don't push the frequencies as high, to keep prices down.

    I saw this in an interview...if I can find the link, I'll post it...
     
  15. AppliedVisual macrumors 6502a

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    #15
    It's only a difference of 25MHz people... Actually, there are plenty of X1900 cards out there that run at the same 600MHz clock that Apple has set their cards to (actually, it's clocked by whoever is manufacturing these cards for Apple). Other reasons for the slightly lower clock speed vs. some of the more mainstream PC versions is production volumes/yields, or it could be due to overall heat requirements within a Mac Pro. Perhaps they had to go with the slower clock to meet the heat requirements laid out by Apple? These sytems run hot and have to move a lot of air to keep from burning up. Just look at the heat spreaders on the FB-DIMMs. There's decent airflow over them, but the air is already hot by the time it gets there...

    FWIW, the X1900XT option is still the best overall graphics card for the Mac Pro right now. It still kicks the snot out of any of the 7300GT cards -- even under WinXP using hacked SLI drivers with two 7300's. The FX4500 has it beat for some things, but it's not even worth considering at the current Apple rip-off price unless you need the specific support for the extended buffer abilities and extra precision... If you're not sure if you need that, then you don't need it.
     
  16. Origin macrumors regular

    Origin

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    #16
    Can anyone explain me, in the case of a real underclocking, the great overall score of the MacPro w/ X1900 XT under 3DMarks that's higher than a regular PC X1900 XT w/ a regular Conroe/AMD ?
     
  17. mmmcheese macrumors 6502a

    mmmcheese

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    #17
    The PC cards that run at 600MHz have fewer pipelines as well...so even though the Mac version runs at 600MHz, it's still a faster card.
     
  18. Transeau macrumors 6502a

    Transeau

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    #18

    The Processors are in front of the memory... The heat from the processors blows on the memory, not the other way around. Air is pulled in via a fan directly in the front and blown onto the processors, then to the memory.

    As far as the heat sinks on the memory, I haven't noticed ANY increase of temp or noise. (I've replaced the stock 1GB with 8x1GB Kingston FB-DIMMs)
     
  19. NATO macrumors 68000

    NATO

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    #19
    This isn't really what happens. The air is drawn in by a fan at the front which passes over the Xeon heatsinks (heating the air slightly of course) and it then passes over the memory. This will further heat the air, but not in the way you describe.

    The heatsinks are there purely to protect the memory itself, NOT to stop the case temperature rising. The memory will be producing the same amount of heat regardless of whether there are heatsinks or not, the idea of the heatsinks is purely so that the heat is drawn away from the IC's on the memory and transferred to the air as quickly as possible. The heatsinks will actually result in a slight case temperature increase simply because that's what they're designed to do.

    Also, the hot air expelled by the fans at the rear of the system won't enter the system at the back, the graphics card has another supply of air passing from front to back, and it expels its hot air through it's heatsink/fan assembly directly out the back of the case. You won't get a 'recirculation of hot air' scenario as you describe.
     
  20. Pressure macrumors 68040

    Pressure

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    #20
    In the quiet words of the virgin Mary, come again?
     
  21. br0adband macrumors 6502a

    br0adband

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    Aug 29, 2006
    #21
    You're right, you're right, I apologize for the fan direction, my mistake.

    I'm so used to thinking about PCs with the left side of the chassic open to work on them and from that perspective - looking into a typical PC case where the case front is on the right side and the rear is to the left - that I forgot totally how MacPros have a removable panel on the right side of the case, making the front on the left, rear on the right.

    Backwards, ain't it? But then again, it's definitely a case of "thinking different," no pun intended. :)

    Thanks...
    bb
     
  22. br0adband macrumors 6502a

    br0adband

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    #22
    It means if you have the Mac version of the card, iirc it has twice as many pipelines as the PC version of the card running at the same speed (meaning both at X1900s at 600MHz). So, theoretically (and probably completely factual also) if you have the Mac version with more pipes it processes more data in the same time, hence, it's faster.

    I think... :rolleyes:

    bb
     
  23. bousozoku Moderator emeritus

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    #23
    It's a professional machine meant to be used in an office of graphic designers generally. Gaming machines have a different goal but even if Apple sold gaming systems, they'd be quieter than most systems running Windows. It's been said that Steve Jobs wants a nearly silent machine and the company goes to great lengths to create cooling that doesn't get in the way visually or audibly.

    Sad that the video hardware is underclocked, but the slower is cheaper method often works unless we're paying the same or more than the Windows users are for the same hardware. (I paid more for my modified Radeon 9600 that works in my Quicksilver than you could find them at Best Buy...grrr.)
     
  24. knome macrumors 6502

    knome

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    #24
    yea we should just be happy that we have the ability to power the card back up, Unlike the issue with the older powerbooks where they were severly deprived of power.
     
  25. mmmcheese macrumors 6502a

    mmmcheese

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    #25
    Well, not twice as many...but more. The 600 MHz parts are typically overclocked "GT" models (usually called GTO and GTO2), which only have 36 pixel pipelines...where as the full blown x1900 parts have 48.

    http://www.ati.com/products/radeonx1900/specs.html

    Even so, this only applies to the PC parts...the mac versions have different clockrate specifications (according to the interview article I read, because of quantities....to keep prices down on those parts, they don't clock as aggressively).
     

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