nForce Speculation

Discussion in 'MacRumors News Discussion (archive)' started by arn, Jul 29, 2002.

  1. arn
    macrumors god


    Staff Member

    Apr 9, 2001
    The Inquirer speculates that chip positioning on the leaked PowerMac Motherboard may hint at an NVidia NForce 2 connection with the new PowerMacs:

    The one chip in recent years to buck the trend is Nvidia's nForce northbridge, positioned at 45 degrees to a mobo's main axes. Alas the blurry snapshots of the alleged Apple product make the info printed on top of the part unreadable, but its positioning strongly suggests the inclusion of Nvidia technology.

    The chip in question is pictured here (Tom's Hardware), which in this photo does not resemble the chip on the leaked PowerMac motherboard.

    nForce on Apple speculation was sparked by an out-of-place reference on NVidia's nForce 2 specs pages on one feature that is not currently available on Mac systems.
  2. macrumors member

    Apr 2, 2002

    this coupled with the quad-processor rumor at MOSR make for a nice mac fantasy.
  3. macrumors 68020


    May 9, 2001
    Interesting... interesting that we are getting more video ram than Mhz...Mmm, I couldn't care less about video ram at this point. With 8 or 16 I'm fine but where are the stuff we really care about?
  4. arn
    thread starter macrumors god


    Staff Member

    Apr 9, 2001
    NForce 2 is not just a graphics card. It's a chipset/motherboard.

    When purchasing a PC, the chipset is all too often overlooked, which is unfortunate because the performance of a computer depends on it. The chipset in a PC can make as much of a difference in performance as, say, the difference between using an Athlon XP 1600+ and an 1900+. And this is no joke: while the first DDR chipsets for the Athlon were faster than their SDRAM ancestors, they were always significantly outclassed by the generations that followed. In the end, pure processor power is not enough if the system itself puts on the breaks.
  5. job
    macrumors 68040


    Jan 25, 2002
    in transit
    Hmm...interesting news.

    But would it really be possible to incorperate a G4 chip on the nForce motherboard?
  6. macrumors regular

    Jan 23, 2002

    Now, I understand what DDR is, SDRAM that talks to the chipset twice each cycle.. but what is DUAL DDR ???

    Furthermore.. how will we know, when the powermacs come out.. wether or not there is a DDR connect between the chipset and the CPU, not just the chipset and the memory ?

    I'd be happy to have someone knowledgable explain.

    Thanks, Funk
  7. macrumors 68000


    Jul 9, 2001
    London, UK
    Dual DDR is what the Pentium 4 has, but I have no idea of how it works.

    I can't see Apple ever using the Nforce Motherboard on G4 chips, but they may use them in Macs. I heard half a year ago that Manchester University (UK) had developed special code morphing software that allowed chips to emulate other chips. One of the examples they gave was the AMD Athlon emulating a PowerPC G3, where a 500Mhz AMD chip was 90% the speed of a 500Mhz PowerPC G3 chip. The G3 could only emulate the AMD chip at about 70% of the speed. I saw the article in the UK PCW magazine. Manchester University also managed to make other chips emulate each other like the Power4 and the MIPS.

    So it is possible to run Mac OS X on a 2Ghz PC and be the fastest Mac so far. This is the only way I think that we will see the Nforce in a Mac.
  8. macrumors 6502a


    Jun 12, 2002
    Where the air is crisp
    so, I thought the nForce was 'low end' or 'entry level' graphics, all bundled up in a nice package but still not targeted towards high end graphics...would this make sense in a new 'pro' model ? Could you use this onboard processor just to run Quartz extreme and a high-end card for the actual content ?

    I am confused :confused:
  9. macrumors regular

    Jan 23, 2002
    That's the CPU!

    One more thing.. if you look closely.. you'll see that is simply the exact same chip as the daughtercard closeup pic shows.. if you rotate the daughter-card.. then everything matches up with the "wide view" (with the graphics card obscuring some stuff).

    I'm sorry to say this, but thats just a G4 chip , nothing more.

    Everything matches up, the little yellow things, and the other chips. From the closeup, we can clearly determine that it's not a nForce chip we're looking at, but a CPU. :(

    I'd love someone to prove me wrong tho ! :)

    [Apple Legal doesn't like these pictures to spread :) ]
  10. job
    macrumors 68040


    Jan 25, 2002
    in transit
    I think the nForce does have a dedicated AGP slot, but don't quote me on that....:)
  11. job
    macrumors 68040


    Jan 25, 2002
    in transit
    Re: That's the CPU!

    Very true...but I can dream can't I? :) :)
  12. macrumors regular

    Jan 23, 2002

    as arn said: NForce 2 is not just a graphics card. It's a chipset/motherboard.

    In particular the nForce2 is a chipset that controls the rest of the motherboard.. while nForce (1) was a IGP (integrated graphics Proc) , nForce 2 can either be a SPP or a IGP, that is to say.. it can be offered just fine without the integrated graphics. The nForce 2 is a chipset in it's own right, it is no longer only a integrated graphics solution.

    In plain english this means that Apple could integrate the nForce 2 chipset into the MB, but still use removable graphics cards. I highly doubt that Apple would choose to use integrated graphics in it's pro line.

    However, as I noted above.. I dont think thats an nForce 2 chip we're looking at.. it's a G4. If u need more info.. look at the tom's hardware link Arn gave us.
  13. macrumors regular

    Apr 26, 2002
    Note that according to the posted specs the nForce2 does NOT support multiprocessor configurations. So I doubt Apple will use an nForce2 chipset as it is in it's current form. Pray for DDR400 though. It would help to feed much more data to the vector unit on the G4 (AltiVec) which is usually starved for data.
  14. macrumors 6502

    Jul 3, 2001
    It's actually dual channel DDR, which works like RAID but then for ram. Delivers higher bandwidth/throughput than normal DDR.

    edit: with 2 standard DDR modules you get almost twice the bandwidth
  15. Moderator emeritus

    Mr. Anderson

    Nov 1, 2001
    Well, seeing the pic again, I have to go with it not being a nForce chip - but no one has asked why the damn thing is 45° off the rest of the board? What benefit does this have? Weird.....

  16. macrumors regular

    Apr 26, 2002
    Dual DDR is just DDR with two memory controllers and two channels to main memory.

    As for code morphing software...ever seen HP's Dynamo software. It is somewhat of a code morphing software that runs PA-8000 code on PA-8000. Supposedly they get up to a 20% performance boost by using dynamic optimization of code at runtime above what a compiler can do at compile time. Neat stuff. Check out Ars Technica's review.
  17. macrumors member

    Jun 4, 2002
    Interesting stuff... I went looking and found this article for those interested in reading about it. Here is a link to the company itself:

    Interesting point in the article :- CPU makers may be a bit worried. Also, if I could run OS X on my Athlon, why would I take the plunge and move my desktop to Mac (as well as my lappy).

    Still, an interesting technology though...

    -- Dan =)
  18. macrumors regular

    Jan 23, 2002
    Most importantly

    Well.. nForce 2 or not (not, methinks, but anyhow.. ),

    how will we know, when the powermacs come out.. wether or not there is a DDR connect between the chipset and the CPU, not just the chipset and the memory ?

    Someone mentioned this being a problem, as, in the current Xserves, the new macs might have DDR to the chipset, but only SDR to the CPU from the chipset.... doesnt this defeat the point of DDR in the first place ?
  19. macrumors regular

    Apr 20, 2002
    Milwaukee, WI
    Re: Confusion

    Dual DDR isn't really a specific technology, it's a feature of the architecture of nVidia's nForce (and nForce 2) chipsets. Specifically, it provides two independent 64-bit DDR channels to memory.

    In a system using the built-in graphics, one of these channels is decidated to the graphics processor (which uses system RAM) allowing it achieve full performance without stealing memory bandwidth from the processor (which still has a full-width memory bus of its own).

    In fact, the speed of DDR meant that on the original nForce chipsets, the onboard GeForce 2MX could be considered to be running at AGP6X, because it actually had more memory bandwidth than an AGP4X socket could provide.

    With the onboard graphics disabled, and a video card in the AGP slot, both of those memory channels are, in theory, available to the system. My old PC has an nForce-based motherboard and, until they upgraded the BIOS and motherboard drivers to allow the system to more flexibly configure the memory controllers, it was back to the days of paired memory banks, where having DIMMs in banks 0 and 1 gave half the bandwidth of having the same two DIMMs in banks 0 and 2.
  20. macrumors newbie

    Jul 29, 2002
    Apple might give up Multiprocessors

    If it is true about nForce 2 not being able to have multiprocessors, I have a reason why this wouldn't matter to apple, but then I have a argument against following that:

    Was it the 603e or the 604e(or both or something like that) that supported multiprocessors? Apple gave them up when they moved to the G3, so maybe they could give them up when moving from the G4 to the nForce2(I'm not sure if they will or wont).

    But then again back in the days of the old multiprocessors there weren't that many Applications in the Mac market that took advantage of them(compared to now that is), and I'm not even sure if the Mac OS during that time did.
  21. Moderator emeritus


    Oct 5, 2001
    San Diego, CA
    I've seen similar layouts on PC's a method of shortening the traces between chipsets, etc....that's about all I know.:)
  22. macrumors regular

    Jan 24, 2002
    3rd star to the right
    Re: Apple might give up Multiprocessors

    The 604e and G4 support multiprocessing.
    The G3 *does not* support multiprocessing.
    That is why Apple didn't make them,
    not because they "gave them up".
    Their markets are screaming for MP systems.

    There were quite a few MP-saavy apps back in the PPC 60x
    days, most notably Photoshop and After Effects. The MacOS
    was never MP-saavy, not before MacOSX. That was a major
    reason for the move, all so that you and I could have rock-solid
    MP-Macs to rule the world, and finish our work so we can go
    home early!!

    And Rower_CPU is right. My buddy makes the SW that optimizes
    those trace lengths in creating circuits. The same should go for mobos.

    And finally, that's a G4. Tell me it has no resemblence to
    Yeah right.
  23. macrumors 65816

    Aug 20, 2001
    nForce2 info

    First, for some background, the nForce2 as it currently stands is a chipset for AMD's Athlons that continains a GeForce4mx core and uses two "side by side" channels of DDR RAM for both system memory traffic and video memory traffic. Each RAM channel can run at 133x2, 166x2 or 200x2, but the DDR-400 RAM really isn't available. Performance of the similar nForce1 was sometimes as high as a low-end GF2MX, and so we could assume (based on other info as well) that the nForce2 will sometimes get as high as a slow GF4MX, but usually will not.

    First major point: it does not offer revolutionary graphics or system performance compared to the way Apple currently has things set up. The dual-channel RAM does not offer an appreciable performance boost for Athlon systems.

    Sub-point: Dual-channel double-data-rate is not at all the same things as a single-channel quad-data-rate, such as seen on the Pentium4 FSB. Since "QDR" RAM does not currently exist, there is actually nothing directly comparable to dual-channel DDR other than quad-channel SDR, which I think has been done on some small-market high-end systems. (Quad-channel SDR is actually the better of the two, but very hard to do.) And there are even more options, such as 128-bit wide memory channels that are like dual-channel but are "joined at the hip", but lets not go there.

    Second major point: nForce1+2 both support a nomal AGP slot, which means they can use faster video cards no problem.

    Third major point: Since the nForce2 is using the AMD-compatible FSB, it would need changes to work with G4's. It is the AMD system bus that does not allow dual CPU's... this means that Apple could still support dual G4's on a nForce2-for-Apple motherboard.

    Sub-point: A dual CPU Athlon needs dual FSB's as well, unlike dual CPU P3's, Xeons' and G4's, where the CPUs share a FSB. Because the nForce only supports one FSB, it can only support one Athlon. The FSB is incompatible with P3's or P4's (although this could be changed, and nVidia could offer an P4 version along side the Athlon and hypothetical G4 versions).
  24. macrumors regular

    Jul 8, 2002
    The dual-channel RAM does not offer an appreciable performance boost for Athlon systems.

    That's because the link between the Athlon and the northbridge is limited to 2.1GB/s, so any memory bandwidth over that point is pretty much unusable by the processor.

    that goes for dual channel DDR AND for PC2700 ram.

    It is the AMD system bus that does not allow dual CPU's.

    Almost but not quite, the EV6 (Alpha) bus the Athlon uses is point to point (eg, you need an extra bus for each processor.)

    Dual processor Athlon's are quite possible, eg Tyan Thunder K7X
  25. macrumors regular

    Jul 22, 2002
    Finally at the end of this thread ddtlm and Chyrx get the facts straight.

    I want to go on record here that I think in August, new powermacs will have an nForce2 chipset with HyperTransport. Even with no upgrade in processor speed this will create a much bigger pipeline, thereby increasing performance.

    When this comes true, I'll direct everyone back to this post and say:

    "I told you so."

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