So what does more RAM really do?

Discussion in 'Buying Tips, Advice and Discussion (archive)' started by xmozx, May 6, 2005.

  1. xmozx macrumors newbie

    May 4, 2005
    I'm a possible switcher in the market to buy a 15" G4 powerbook for my MBA graduate program. I'm already over the whole, "should I wait for the G5 powerbook thing", because I am sure that a maxed G4 will be fine.

    But my question is, what does maxed out RAM really do for the average user, and what are other ways to get a powerbook G4 to run at it highest performance? Currently, I have a desktop Dell with a 2.4 Ghz Pentium 4 processor and 512 Ram. Will I notice a difference?

    Thanks, I am an experienced end user with little knowledge about the actual technology. I just know what I like when I use it.

    Thanks for helping me out.
  2. Godflesh macrumors newbie

    Apr 29, 2005
    I've just switched to a 12" 1.33 PB G4 from a AMD Althlon 1800 512 with XP Pro. I haven't used a mac since the SE/30 days.

    I ran the PB at 256 for 3 days while I waited for the RAM upgrade (an additional gig.) I use email, newgroup reader, image veiwer, firefox, quicktime, iChat. All of those things functioned fine with 256 meg. I run all the programs at once, just like I would on my PC.

    With the 256, I could get stuff done. Things did not seem quicker than my XP box, but it was not slower either. The user experience was better than XP. Multitasking did not come at a large price.

    However, the 1.25 gig configuration made the menu selections faster, the reaction to commands faster, the window switching faster, you name it. On of the reasons I bought the PB with the slower HD and processor was so I could immediately max out the RAM. Made a wonderful difference. For sure worth $150.
  3. jsw Moderator emeritus


    Mar 16, 2004
    Andover, MA
    OS X - as with most modern operating systems - makes extensive use of virtual memory (using disk storage as memory, which allows more but much slower memory).

    The more RAM you have, the less often the computer moves things between RAM and the hard disk, which translates to less waiting on your behalf.

    Depending on your usage, 512MB is quite likely to swap noticeably at least occasionally (256MB will swap noticeably quite frequently), but it might not be a problem for you. 768MB or, preferably, a GB or more will produce very infrequent swapping, meaning you can have more applications open - and painlessly switch between them - than you could otherwise.

    Smaller amounts of RAM don't stop you from doing anything - the hard disk can be used to make up for it. It can just slow things down a lot.
  4. jsw Moderator emeritus


    Mar 16, 2004
    Andover, MA
    And, as mentioned above, the cost for quality 3rd-party RAM is about $150 for a GB. Given that the 15" now comes with 512MB, for $150 you can upgrade to 1.5GB, which is a very useful amount (good enough for the vast majority of users) for a small investment.
  5. wiseguy27 macrumors 6502


    Apr 30, 2005
    Many people seem to believe that there would never be a G5 powerbook (because of heating and power consumption concerns). Anyway, there are many opinions about it.

    Note to other geeks: This is a slightly simplistic explanation.

    Maxed out RAM would make your apps run faster, especially if you open multiple applications simultaneously.

    If you dig deeper into the technology of operating systems, you'll read about "virtual memory" and "swapping".

    The first thing to know is that CPUs can only run programs that are present in RAM (if they're elsewhere, like on a hard disk or other device, they have to be fetched to the RAM first). **

    All modern operating systems isolate the memory aspect from applications. They also allow the user to set aside some "swap space" (or pagefile in Windows). This is space on the hard disk that is used to emulate RAM - so if you run many apps simultaneously and the OS finds that one of the applications needs more RAM, then it will decide which parts of the other applications can be "swapped out to disk temporarily" so that the RAM in use can be given to the application that needs it. When the (swapped out) applications want to access what they believe is in RAM, the OS swaps the data back into RAM transparently to the application (possibly by pushing something else to the hard disk, depending on the memory usage). [See ** above]

    Since hard disks are a lot slower than RAM, swapping data in and out of RAM from/to the disk takes a lot of (noticeable) time. Whenever you see your hard disk activity going up without a user initiated disk activity, it is the OS swapping that's most likely the cuplrit.

    Assuming the number of applications you open simultaneously is fixed, you can do the following to improve swap performance:
    * provide more RAM so the OS would have to swap less (theoretically). This would make your application and OS response times better.
    * make the swap itself perform faster by getting a faster hard disk (which usually may not be easy or possible for notebooks)
    * optimize the number of times swapping is done by increasing the swap/virtual memory a little more (this can be overdone and could result in poorer performance too).
    * For desktops, make the swap perform faster by putting the swap/virtual memory on a physical hard disk other than the main hard disk (so the swap access happens independent of data access on the main drive).

    If you do not increase RAM, then open fewer applications simultaneously to improve performance.

    I have no idea about the comparison of the Dell though.
  6. macorama macrumors regular

    Apr 14, 2005
    And since the original question was about a laptop, that's doubly the case, as laptop harddrives are even slower than on a desktop. So to answer the original question which was about a 15" powerbook, you should go for all the RAM you can afford. 1GB is probably close to the sweet spot for a powerbook.
  7. GoldenHoya macrumors newbie

    Apr 29, 2005
    Berkeley, CA
    Where can I get a gig for $150?

    I'm a recent switcher and am thinking about purchasing more RAM. I've looked for RAM online aready and the best I've found is $80 for 512 and $370 for 1 gig. Where can I find it cheaper? If I could find a gig for $150 (as was stated above) I'd buy it right now.
  8. edwardk9 macrumors member


    Apr 24, 2005
    #8 has ram for cheap. I am new to mac so I would assume the RAM would work on either.

    My friend has a mac mini and bought a gig of ram for 70 bucks and it works fine in the mini.
  9. admanimal macrumors 68040

    Apr 22, 2005
    I have a 2.4GHz PC running XP with 1GB of RAM (about to be replaced by a 20" iMac as soon as FedEx shows up with it), and a 12" iBook with 256MB. Obviously I'm used to the PC being very responsive, but I have to say that the iBook does very nicely with only 256MB. I don't push it as much as the PC, but I would imagine with 512, the iBook (and PBook) would handle a decent load.

    It is true that adding more RAM is going to give you some noticable improvement no matter how much you tax your system until you get into the 1GB+ range, at which point you won't notice the benefits of adding more unless you are running some memory intensive programs. Practically speaking, when you start considering whether to go beyond 512, you need to ask yourself what you will be doing with the computer. If the answer is just the standard "email, internet, word processing, iTunes, iPhoto" maybe with a little iMovie or something thrown in, then 512 will probably be a good number.

    Having more memory never hurts, but having 1GB+ is not necessary for the common user.
  10. Mechcozmo macrumors 603


    Jul 17, 2004
    Actually, because you can't upgrade the processor and its hard to upgrade the HD, its a good idea to get the BEST possible, and then after you have accumulated some more money, you get your RAM (not from Apple) and upgrade.

    Video Card-- get the best possible
    CPU-- depends, preferably the best, but you can choose
    HD-- fastest spinning is good, makes a big difference in terms of speed.
    RAM-- it can always be upgraded later, unlike most of the other things

    That's all for laptops, BTW. With a desktop, a fair amount can be upgraded later. But still applies in basics.
  11. xmozx thread starter macrumors newbie

    May 4, 2005
  12. Silver Surfer macrumors newbie

    May 9, 2005
    I'm a recent switcher and I purchased my Mac mini with 512 RAM. That was perfect for Panther, but for Tiger I wish I would've went with 1 GB of RAM. I see the Beachball of Death every once in a while when I open up a application, but that's when I have iChat and iTunes already open.

    When I upgrade to a PowerMac I'll go with at least 1 GB of RAM.

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