32-bit and 4gb memory limitation????

Kkkk1

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Folks,
I just about to upgrade my PC. I'm going for 3Gb tri channel memory and the 4870X2 amongst other things. My question is I know 32-bit can only address around 4Gb of RAM, however with 3Gb RAM and 2Gb video memory making 5Gb will Vista 32 not recognise all that RAM? Or does your main RAM and video memory work independently making Vista 32 suitable for my needs?

Thanks.
 

emp

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1.) why are you even bothering with Vista 32? It was made for legacy hardware in mind (Think Pentium 4s and Athlon XP).

2.) Are you getting a Core i7 platform? It's really a waste to get only 3GB of memory on a Core i7 platform.

And to answer your question, yes it will limit you some, probably recognizing around 2.5GB-2.7GB of memory.
 

IH8U

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Welcome back Strange. To answer the question The PC cannot use the RAM on the GFX card (only the GFX card can). So if you install 3 GB of RAM, That is what you get (minus what the system/GFX card uses) to anywhere from 2.2 to 2.7 usable by the PC. Take the suggestion use a 64bit OS (don't bother with Ultimate, I'm paying for that mistake), that way you can install as much RAM as you want (limited by the MB of course).
 

smartel7070

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Very Good question !! I just made the switch from XP32 to Vista64 and everything works just fine, hardware and software. I really don't understand why so many people install Vista32 on brand new systems.
 

Kkkk1

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Alot of people i've spoken to say there are lots of games that won't run of Vista 64. Is this true? Also I am getting the i7 920 but why is it a waste to only get 3Gb? I know people always bang on about Crysis but task manager is only using 1.2Gb on my current system so i was thinking 3Gb would be plenty for now. Am I missing the point?
 

smartel7070

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I've had no problems with games either with Vista64.

4gb is the minimum for smooth operation in Vista. If you have the budget go for 6gb as you are getting an i7. I will upgrade to 8gb probably after the holiday season.
 

EXT64

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I'm assuming that is 1.2GB just idling (with nothing open). Many games an really gobble down ram (besides Crysis). My current Vista 32 is tweaked down so it only uses 400MB or less with nothing open, yet it can still start running low on ram (I have 2 GB). That's why I'm going to Vista 64 and 4GB in my next build. I think 64 is fairly stable now. Do you have both versions (32 and 64)?
 

aznguy0028

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take it from a hardcore gamer, A LOT of games run on Vista 64. it depends on what games you're talking about and how old? All my games run fine with no hitch at all. the people you talked to are either never tried Vista64 before or they are playing games made in the 90's which in that case i'm not sure.

starcraft is probably the only 10 year old+ game i play and it's fine on Vista, anything older than that, i don't know, anything newer works like a charm. 4gb is the new standard for DDR2 ram since it's so cheap, but if you're going to build an i7 build, you have to go with 6gb. you'll most likely end up upgrading to 6gb later from the 3gb.
 

MarkG

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Traditionally, video memory was mapped into the CPU address space so that the CPU could write directly to it (e.g. for transferring large textures over or for writing video data to an offscreen buffer). I don't know whether that's still the case now that cards can have 1GB+ of RAM rather than 64MB.

Obviously if you have 2GB of video memory mapped into your CPU's address space in the first 4GB range then you can't use more than 2GB of system RAM.
 

sailer

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I've had pretty much the same experience as aznguy. The only games I have that won't run on Vista64 are so old that they require single core processors, and I've long since gotten rid of my last single core processor. I totally agree with those who say to get Vista64 over Vista32. There is no sensible reason to put a 32 bit OS on a modern computer.

While 3 gig of ram isn't a waste, it will limit you very quickly and slow down the game play as you end up using the hard drive as virtual ram. This situation will only worsen as the years go by and games get even more complicated. Get the 6 gig package and be happy.
 

Kkkk1

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OK I think the consensus is get Vista 64 which i'll have to do. At the moment I run XP pro so will have to buy Vista. Also while 6 Gb of ram would be nice I really don't think my budget will allow at the moment. I suppose I could drop the 4870X2 and go for 48701Gb and get the extra RAM then add another 4870 at a later date. Does anyone think that might be the better option? Or just use 3Gb now and upgrade to 6Gb later?

Many thanks for all your posts.
 
G

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video ram IS NOT SEPARATE... its an urban legend it is separate...

If you install 3 gigs of ram with the 4870 x2 you'll see a total of about 2.2 - 2.5 gb of physical ram

First the 32 bit operating system can address max of 3.5 gb of ram... generally more like 3.2 gb after all is said and done... then... 1 GB of vram is subtracted (1 gig and not 2 since the video card doesn't actually use 2 GB)

AND WALAH!!! you come out to your magical number



About your budget... if you don't have enough to get what you want... DONT GET IT... save up for another month... spend the under 100$ and get 6 GB of ram... your getting an x58 platform what do you expect?
 

smartel7070

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Regaring your video card question it really depends on what games you play and also what resolution. And also how long do you plan to keep the card ? I change video cards every 6 to 9 months.

For most games,if you play at 1280*1024 then a 4850 512 would be fine. 4870 512 will allow more eye candy. 4870 512 will even handle 1920*1200 with no problems at all.

I have a 4870 512 and I play @ 1920*1200. Games I play right now are COD4, Fallout3, FarCry2 and they all run great, mind you I only use 2xAA which I think is more than enough at that resolution.

Again the question is how long do you plan to keep the card ...
 

GenRabit

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With a 2GB graphic card you will be down to 1.5-1.7GB ram. Reason is that the graphic card needs the addresses, and these two GB on top is chewed away. So get a 64Bit Vista and the cards Addresses will be put far out ot your memory range.
 

notherdude

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video ram IS NOT SEPARATE... its an urban legend it is separate...

If you install 3 gigs of ram with the 4870 x2 you'll see a total of about 2.2 - 2.5 gb of physical ram

First the 32 bit operating system can address max of 3.5 gb of ram... generally more like 3.2 gb after all is said and done... then... 1 GB of vram is subtracted (1 gig and not 2 since the video card doesn't actually use 2 GB)

AND WALAH!!! you come out to your magical number



About your budget... if you don't have enough to get what you want... DONT GET IT... save up for another month... spend the under 100$ and get 6 GB of ram... your getting an x58 platform what do you expect?
First the 32 bit operating system can address max of 3.5 gb of ram
This part is incorrect. Actually a 32 bit os can address 4 gig of memory! THEN you minus the other devices that have ram on them such as video ram. This is how you end up with typical amounts of 3 to 3.5 gig. 2 to the 32 power is 4 gig, that is the 32 bit limit. If you have a massive amount of video ram this might dip your 3 gig system down below 3 gig of usable ram.

If you are correct about a 2 gig video card not using all of it and only using 1 gig then it seems possible that on a 3 gig system you will be able to use all or nearly all of your 3 gig of system ram. If a CF or x2 card only uses 1 gig is what I simply don't know.
 
G

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the most i've ever seen it address with a integrated graphics card is 3.5 gb of ram... never seen it address more space than that (integrated graphics had like no ram either :na:)

Either way thank you for your correction :)
 

WR

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First, I'll reply with what Vista SP1 32-bit reports to me on System A. I have 2 x 2 GB RAM installed and a 3072MB page file. Video card is a GTX 280 (1 GB VRAM) and resolution is 1650 x 1080 32-bit. Firefox and a few background apps are running - consuming 110 MB RAM under Task Manager.

Physical Memory (MB)
Total 3070
Cached 2257
Free 132

Page File 996M/6039M


Next, System B has 2 x 512 M and 2 x 1G for exactly 3 GB of installed RAM. Page file is set at exactly 1536M (or 1.5 G). GPU is a Radeon x1900xtx (512 MB VRAM), set at the same 1650 x 1080 resolution. This one runs Windows 2000 Professional SP4. Firefox and a DX7 app with background processes are open - using ~200 MB RAM.

Physical Memory (K)
Total 3112172
Available 2542800
System Cache 610740

Commit Charge (K)
Total 669380
Limit 4553604
Peak 670612

With two copies of Prime95, I'm able to load almost the entirety of remaining physical memory on either system with no persistent thrashing. (Windows always frees up a little extra space, so task manager would say ~2.98G used.)

3039.2 MB RAM displayed with 3072 MB installed, using a 512 MB video card.

3070 MB RAM displayed with 4096 MB installed, using a 1024 MB video card.

At least I fail to observe something approaching the 2.2-2.7 GB region that others are mentioning. Does anyone have something closer to the OP's system than my System B?

Thogrom's 3.5 GB theory would explain my System B if only System A reported 2.5 GB available, since it has a full 1 GB video card.

4gb is the minimum for smooth operation in Vista.
Also while 6 Gb of ram would be nice I really don't think my budget will allow at the moment.
That is the primary reason I'm on 32-bit Vista. 3 GB under 32-bit is like at least 4 GB under 64-bit. You spend more money on RAM to have the same effective space under 64-bit. If you need the space, you have no choice. I just don't need it yet.
 

notherdude

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the most i've ever seen it address with a integrated graphics card is 3.5 gb of ram... never seen it address more space than that (integrated graphics had like no ram either :na:)

Either way thank you for your correction :)
We are not talking about integrated graphics cards.

A 32 bit OS can generate 4 gig of addresses (2 to the 32 = 4 gig) so 4 gig is the total address space the OS can work with. Since the OS must address video ram (and the ram on other devices) it must reserve some of its 4 gig total addresses for those devices. It takes this address space of the top off the 4 gig of addresses (not off the top of your 4 gig of system ram, no system ram is being used here, it only goes UNUSED) and leaves the rest of the address space for system ram. The one gig or so of system ram that goes unused in a 4 gig system is not being used by video or anything else, it just sits there totally wasted because the OS simply does not have the addresses available to fill it up. Integrated graphics is a different case because integrated graphics actually uses system ram, it shares it with the system. This too reduces your total ram but for a different reason.
Gaming systems don't often have integrated graphics using shared ram. They have dedicated ram on the card. The amount of dedicated video ram will be subtracted from your 4 gig of address space, however, if you only have 3 gig of ram on your system that extra gig of address SPACE is not needed, hence you usually lose little or none of your three gig of installed system ram even when you have a lot of video ram, up to about 600 meg or so. If you have massive video ram you can even lose a sizable chunk of ram from a three gig system.
 
G

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And that ^ is why I am still a teen, can't write coherently for long :na:

Nice post :) really clears it up for the thread, I'd actually refer back to that post if this ever comes up again, but considering the search function on tomshardware sucks... probably won't happen.
 

WR

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Yeah, that and GenRabit's link really explain the issue. Except for this lingering question. Does the 4870 x2 at 1 GB per core count as 2 GB or 1 GB of addressable space?

A valid test would be any 32-bit Windows OS, a 4870 x2, 3+ GB installed RAM, and a task manager SS. Anyone?
 

GenRabit

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Probably two. After all the two cores won't show the same.. One renders the upper part, one the lower.
 

MarkG

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Actually, a 32-bit x86 OS can address 64GB of memory, but 32-bit desktop Windows versions won't.

The 4GB limit is per-application, but the CPU can handle 64GB of physical memory; Microsoft only allow that on server versions of Windows. 32-bit PAE Linux kernels, for example, can manage 64GB of RAM.
 

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