How Important is System Bus?

Discussion in 'Macintosh Computers' started by esotu, Jun 2, 2004.

  1. esotu macrumors member

    May 31, 2004
    My plan is to buy an older G4 model and upgrade it. I'm looking at the old Sawtooth, Gigabit/Ethernet, Digital Audio, and Quicksilver models.

    I'm wondering if the small increase in price for the DA and Quicksilver models is worth the 33MHz more of System Bus. I'm going to be doing mainly gaming, so would I see a difference in a 100MHz Bus vs. 133MHz Bus? Also, does anyone have any suggestions as to what model I should buy? I plan on upgrading with an OWC Mercury Extreme 1.5 GHz chip.

  2. Luckster macrumors member

    Jul 25, 2001
    Bus speed can make a major impact. In any modern system, the processor runs significantly faster than the memory bus; the ratio of processor speed to bus speed is the bus multiplier. Basically, the lower the multiplier the better. What happens with a faster bus is that more data can be fed to the processor (called throughput) and the time it takes to start a request is usually lower (called latency). If you have a really fast processor on a slow bus, the processor will sit idle most of the time. To compensate for the fact that extremely fast busses either cannot be built (due to length of the bus) or are prohibitively expensive, caching is used to help make it appear as if the memory was as fast as the processor. If your processor has a large L2 or L3 cache the difference in lessened (for most apps). So, as a long winded answer to your question: it depends. If getting the faster bus is not out of your budget, by all means, do it. If it is not in your budget, you may consider the trade off of a slightly slower processor and faster bus.
  3. TrenchMouth macrumors 6502

    Nov 21, 2002
    what games are you planning to play? if you arent going to play anything all that intensive you might not need the extra 33Mhz, but if you plan to upgrade to a 1.5Ghz G4 then that makes me think you are going to try and run something like UT2k4 on it. You want the extra 33Mhz. But here is the real deal, the late model G4s had a 167Mhz bus, and while i dont remember the speed of the memory they used i am sure its a lot faster than the PC100 types that you will be using. The speed of memory (and consiquently the bus) can have a very big affect on your gaming experience. If you get it on the cheap then go for whatever you can get your hands on, but to tell you the truth you might be better off with a fully loaded iBook, that while not upgradable, will fare better than anything with a 100Mhz bus.
  4. jsnuff1 macrumors 6502a

    Oct 4, 2003
    In that case just buy a 1.6Ghz G5, i dont see the point in buying an old system and upgrading it. It will prob end up costing you more than just buying a new low end system (that is way faster than what your trying to build).

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