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RAM & XP Pro

Discussion in 'Motherboards & Memory' started by llllllllllll, Nov 21, 2008.

  1. llllllllllll

    llllllllllll

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    I was wondering if anyone knew what the maximum amount of ram that XP Pro can support?

    I had heard that it crashes on 4GB of ram..just wondering for a new build.
     
  2. sneekypeet

    sneekypeet Unpaid Babysitter Staff Member

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    It wont crash, I had 4X1gb of tracers on my XP build, but the OS can only support up to 4GB incliuding the Vram on the graphics cards. So if you have a 512 VGA then the OS will only show 3.5GB of actual ram!
     
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  3. spearman914

    spearman914 New Member

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    What the hell? If the older xp can support 4 GB why can't the vista 32 support 4 GB excluding the GFX ram.
     
  4. sneekypeet

    sneekypeet Unpaid Babysitter Staff Member

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    llllllllllll says thanks.
  5. llllllllllll

    llllllllllll

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    Really? That's wild lol. So my new build with a 256mb video card will only show 3.7ish of RAM?

    Thanks for the quick response Sneeky:toast:
     
  6. sneekypeet

    sneekypeet Unpaid Babysitter Staff Member

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    In theory yes that would be the case. Read the MS answer tho just to validate!
     
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  7. Thrackan

    Thrackan

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    It's a 32-bit or 64-bit OS thing. 32 bits is just enough to allocate 4Gb of memory. 64-bits Operating Systems like XP x64 and Vista x64 support way more because they have 64 bits of allocation.
     
  8. Mussels

    Mussels Moderprator Staff Member

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    ^ what thrackan said.

    32 bit operating systems max out at 4GB of address space. System ram, page file, and video card ram all share that space. The more video card ram + page file you have, the less system ram will be available.

    It can cause crashes in odd circumstances - lets say your program uses 3GB of ram and tries to use 2GB of page file... it'd be aiming for 5GB of 4 max (despite the fact both are available and free to use) and crash. Its something that is becoming more and more rare, but for a while games were plagued with it.

    64 bit, has a limit of 128TB of ram. So we wont care for a while.
     
  9. xubidoo New Member

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    in my 2nd rig when i had a 320mb 8800gts in it & 4gb ram it was only showing as i had 3.25gb total ram.
     
  10. Mussels

    Mussels Moderprator Staff Member

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    thats the most common number shown. I'm not sure why, but windows tends to show 3GB or 3.2GB - other numbers are very rare.
     
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  11. Thrackan

    Thrackan

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    Because Windows include pagefile as well:D
     
  12. DanTheBanjoman SeƱor Moderator

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    Because it's not a Windows limitation. 2^32 = 4GB, there simply are no more addresses. Using PAE you could use 2^36 = 64GB, desktop OSes don't fully support PAE though (only for the NX bit). If you want to use more than 4GB of RAM and want to use 32 bit Windows > Server 2003/2008.
     
  13. Mussels

    Mussels Moderprator Staff Member

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    yeah and it defaults to 1.5x the amount of ram in the system. if that logic was true, why arent we seeing people crying about 1GB or less of ram available?
     
  14. Thrackan

    Thrackan

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    My hunch is that it includes all currently allocated bits of the pagefile. But I could be wrong.
    Who am I to know btw, I use XP x64 :D
     
  15. Grimskull New Member

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    vista ultimate 32bit with SP1 can see 4GB of RAM. I have a 4870 512MB card in as well... With XP Pro SP3 it sees 3.25GB. The PC is dual-booted.

    just my two-cents
     
  16. Mussels

    Mussels Moderprator Staff Member

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    it can see, but it cant *use*.
    its merely a gimmick, because people buying systems from dell and other OEM manufacturers, complained "i paid for 4GB of ram, not 3.5GB!"
     
  17. Grimskull New Member

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    yeh your probably right, when i saw it i was like "wtf!! 4GB on a 32bit PC?? when did that happen???!" wonder what percentage of calls did OEM manufactorers get before and after the 4GB switch in SP1 was installed?
     
    Last edited: Nov 21, 2008
  18. Franklinwallbrown

    Franklinwallbrown New Member

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    The real question should be whether or not you are in dual channel when you have 4gigs of RAM and a 512mb videocard on a 32bit OS...
     
  19. sneekypeet

    sneekypeet Unpaid Babysitter Staff Member

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    Absolutely it does run dual channel with 4X1GB stix and my HD3870 512mb card.
     
  20. tong

    tong

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    Windows 32 bit is limited to a maximum of 4 gigs of ram however the OS itself will only see a maximum of 3.25, those that are showing 3.5 are only because you told it to take (amount of memory for video) and dedicate it to video.

    Those that saying they see 3.5 out of 4 gigz because they have a 512 video card --- incorrect, on a dedicated video solution the amount allotted will be used as video cache, on and integrated (built in, shared) video solution it will use that amount as video ram, taking away from the system total of ram.

    To take full advantage of 4+ gigz of ram you need to use a 64 bit OS, weather Vista or XP. Those of you on vista that actually see the 4 gigz or more (32 bit) that's just it u only see it, windows only knows how to use 3 gigz. They did come out with a patch for the 32 bit os's (mainly xp) but all the patch does is make it see the rest of the ram not use it.

    Those running 4 gigz on a 32 bit os - you actually take a performance hit, even though windows might see all 4 gigz it only uses 3, and it doesn't know which 3 out of the 4 ... so guess where your performance hit is? The os slows down trying to keep track of which 3 gigz it can use.

    Now for those of u thinking, well i can put a gig or 512 of that to video cache (like i stated earlier) and take advantage of it.... another performance hit, instead of reading from the HDD directly to the vidcard, you're going to : read from HDD, transfer thru your mem controller to your ram then from your ram thru the northbridge to your vidcard when it needs it. Guess which is faster?

    For those of you reading and odd number (something that's not adding up to what u have in there) check to see if u did allot some of the ram to video. However if the pc is POSTing less ram than u have installed, maybe one of the ram chips on the ram sticks is bad.


    /end of rant
     
    Last edited: Nov 21, 2008
  21. Franklinwallbrown

    Franklinwallbrown New Member

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    No, real need to panic then...
     
  22. tong

    tong

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    I call impossible, unless it's a dual sided stick that is recognized at 2x2gigz instead of 4x1 gigz, the way dual channel works is by using two stick (min) and basicly.... well best way i have to put it is: you're going to a concert/movie and only one door to get in (single channel), they open a second door (dual channel). The doors (memory slots) were alreasy pre-existing however the Valet (guy checking tickets)(ram) was needed for the second door.

    So physically it's impossible to be in dual channel with only one memory stick, ddr3 solved this problem by allowing each side of a single piece of ram to be used as 1 channel even in one slot, but only if the ram is double sided ( having ram chips on each side of the stick), however when ddr3 hits two sticks, this feature turns off and allows each stick to be used as one channel. DDR3 boards (most of them) now support 3 channel, on channel per stick per slot (unless the previous stated supersedes).



    edit: my bad, i miss-understood, thought u meant 4gigz x 1 stick not 4stick x 1 gig each, my apologies
     
    Last edited: Nov 21, 2008
  23. sneekypeet

    sneekypeet Unpaid Babysitter Staff Member

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    All I can say is you are wrong on this, as I and many others have run this way in dual channel.

    EDIT: no screenie from me but this link proves my point. 4X1GB in dual channel mode on XP, reguarless of what amount is recognised.
    http://forums.techguy.org/windows-nt-2000-xp/763032-can-only-see-3gb-out.html
     
    Last edited: Nov 21, 2008
  24. timta2

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    Yes, I too have 4x1 Gigs running in Dual Channel Mode. 2 of the sticks are double sided and 2 of them are single sided.
     
  25. tong

    tong

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    cpu-z ,memory section to show the total and the channels it's running in, then go to the spd section to show how much is in each slot. I could be wrong, as far as i knew they hadn't implemented that solution in the ddr2 boards and were saving it for ddr3 only, however intel keeps popping out chipsets like trailer park trash pop out babies.


    edit: my bad, i miss-understood, thought u meant 4gigz x 1 stick not 4stick x 1 gig each, my apologies
     
    Last edited: Nov 21, 2008

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