Getting new computer - 3 or 4 gigs?

[Ilavatar]

I'm going to be getting a new (Vista) computer soon and I'm wondering if I should spend the money on 4 gigs or just get 3 gigs? I've heard that 32-bit systems can't use 4 gigs and EQ2 can't use more than 2 gigs.On the other hand, I like to run other programs at the same time as EQ@ and switch between them (like quest/raid guides, maps, news stories during slow zoning <img src="/smilies/3b63d1616c5dfcf29f8a7a031aaa7cad.gif" border="0" alt="SMILEY" />, etc.)Would 4 GB RAM help with this?

[OptimusEnd]

<p>If what I was told is correct.....</p><p>A mother board will only utalize the first 3 gigs of RAM and leave the 4th gig (4th slot) deticated to hardware.  </p><p>As for EQ2 I have not idea how much RAM is does and doesn't need/uses.</p>

[Kermos]

You were told only partially correct. Motherboard can be (if it only has 32 address lines) be the issue but necessarily isn't. Operating system and CPU usually are.A 32-bit CPU has 4 gigs of address space. This address space is used to access RAM and peripherals on the motherboard. Peripherals include your video card, soundcard, hard disk controllers, etc.Address space used by one device can't be used by another. So if you have a 512 meg video card, 512 megs of your address space are reserved for the video card in order to be able to access this video memory. The same goes for your sound card and everything else. So all these things chip away at the address space.Whatever is left after all that is what is available for RAM.So that is issue one.Issue two is the operating system.A 32-bit operating system divides the address space further into two regions. Kernel and User.Kernel space is reserved by the operating system for it's own use. That is where all the hardware mapped addresses are contained and OS specific memory is contained. For a 32-bit OS that is the upper half of memory, so 2 gigs. I'm not going to get into the 3G switch as that can come with a whole host of issues and may / may not be a viable option (It isn't an option if most of the upper 1 gig has been mapped to hardware).So that leaves 2 gigs for user space. Each application gets its own 2 gig of virtual user space. Physical memory is paged into this virtual space on an as-needed basis. However, since the virtual space is limited to 2 gigs, it doen't matter if you have 10 gigs of RAM in your system...the app CANNOT use more than 2!There still is an advantage though to having more than 2 gigs of physical ram in the system. If you have one app using 1.5 gigs of memory and another using 1 gig of memory, your total memory usage is 2.5 gigs. If you have 3 gigs in your system, there is sufficient physical memory available but if you only had 2 gigs of memory there wouldn't be enough memory and virtual memory would have to be used.So bottom line: On a 32-bit system, 3 gig's is enough as you're unlikely to be able to use more than 3 gig, especially if you have a 512 meg or more video card.On a 64-bit system though, things change a little bit.Your theoratical address space just went from 4 gigs to about 16,384 petabytes. (1 petabyte = 1024 terabytes = 1024^2 gigabytes). Yes, it's a lot of space and the limit now is the number of address lines actually implemented on the motherboard. The number 128 gigs pops into my head for some reason so that would be 37 out of the 64 address lines. So if you have a 64-bit CPU with a 64-bit OS then if you have 4 gigs of ram every byte of this ram is available. However, there still is a fly in this ointment. If the application you're running is a 32-bit application this does you very little good as the app still is limited to a 32-bit address space. The app however would be able to use up to 4 gigs of RAM, but it's relatively unlikely it will though as it's intended target is a 32-bit processor with a 2 gig user space limit.

[OptimusEnd]

<img src="http://forums.station.sony.com/eq2/images/smilies/385970365b8ed7503b4294502a458efa.gif" border="0" alt="SMILEY" width="15" height="15" />......................... wow....that was a mouthful, but yet educational!  Thanks!

[Kermos]

Haha, thanks. =)Just wait until someone gets me started on why their shiny quad-core won't make their PC 4x faster <img src="/smilies/8a80c6485cd926be453217d59a84a888.gif" border="0" alt="SMILEY" />

[Ilavatar]

Thanks for the great reply above! I also heard that if I get 4 gigs, the system can use 3.5 of that. What's up with that?>Just wait until someone gets me started on why their shiny quad-core won't make their PC 4x fasterCan EQ2 make use of dual-core processors?

[Kermos]

Well my earlier reply contains the answer to your question.What you've heard is only partially correct. If you get 4 gigs, how much out of those 4 gigs you can use depends on your hardware.If say you have a 512 meg video card that is 512 megs of memory you can't use for RAM because that area is reserved for video memory. So that means your total accessible memory will actually be less than 3.5 gigs.This formula is usually pretty good to get a rough idea how much memory you will have available if you put 4 gigs into a 32-bit system: 4096 - video memory (in megabytes) - 256 = Useable memory for a 32-bit system.With a 256 meg video card, expect around 3.5 gigs.With a 512 meg video card, around 3.25 gigs.With a 768 meg video card, around 3 gigs (that's my case with my system).With a 1024 meg video card, 2.75 gigs.As far as EQ2 and dual cores go, your system overall will benefit from having 2 cores or more as it allows the OS to dedicate one core exclusively to EQ2 and still leave everything else responsive by running those tasks on the other core. So the primary benefit is for your operating system in being able to better load balance the load across the cores.However, that's about the end of the benefit.If you have 2 cores, 4 cores, 8 cores or a million cores....it won't make EQ2 run any faster. EQ2 is primarly limited in speed by your video hardware not by your CPU and it only uses one core. Wanna improve EQ2's performance? Improve your video hardware. A client such as EQ2's is something that is very difficult to parallize across multiple cores as most the tasks it needs to do are tasks that can't be done in parallel so a high number of cores does absolutely nothing for it.

[Ilavatar]

Thanks!So it looks like it still is worth getting 4 gigs because it gives you more RAM for your video card to take a bite out of - leaving more left over for the apps. Also, you can use it for the other apps I like to have open at the same time.Does the OS do a good job of keeping EQ2 undisturbed in its own core or should I get one of these programs that makes it do that like Process Lasso which someone in this forum recommended? <a href="http://www.bitsum.com/prolasso.php" target="_blank" rel="nofollow">http://www.bitsum.com/prolasso.php</a>

[Kermos]

Yea you definitely cannot do anything wrong with 4 gigs. =)As far as the process lasso thing goes, while I can somewhat see the merit on a single core system it makes no sense to me on a multi-core system. I personally wouldn't worry about it.