4gb of RAM worth it?

[[FETT]Cupcake]

Hey guys,

I had a question for those who know more than me, which is pretty much everybody here.

I have 2gb of dual channel pc3200 ram. I was thinking about upgrading to 4 gbs because the price is right, and I wanted to make sure I can grab hardware that is still compatible with my skt 939 mobo.

With todays games and operating systems, will there be any benefit going to 4gb?

Right now they are in 1t timing, will going to 4 cause it to slow the ram down? If it does, will it be better to have 4 gigs of the slower ram or 2 gigs of the faster ram?

Any opinions will be appreciated.

[Digger[NJLP]]

Wow 4 Gigs of Ram nice upgrade.

Well unless the logic of the memory bridges have changed dramatically in the last few years, RAM will always clock down.

But even at a slower speed I don't think the negative of slower speed ram will outway the benefits of 4 Gigs..

Every version of Windows has increased the amount of RAM it needs to operate. But if you have enough RAM the biggest benefit has been turning off Virtual Memory.

VM is the practice of swapping the programs currently in RAM to the hardrive(pagefile) to make room for other applications.

With the release of XP and Vista, memory managment has gotten alot better but VM is still enabled unless you turn it off. But you better be sure you have enough RAM to pull it off. Four Gigs of RAM should be plenty and you will enjoy much better responses from programs when you have quite a few open.

For gaming the benefits still apply but it would be smart to take a hard look at your system when your gaming and see how much RAM your using and how big your current swap file is.

The Window Task Manager can do that in real time or you can use the the Performance Monitor and record your level for later evaluation.

If the slower clock speed has a major affect on game play you can always return it. But I still say with 4 gigs you'll be fine.

[[FETT]Cupcake]

Thanks Digger. I'm not sure I'm going to do it, but I just want to make sure I can get the hardware before it becomes unavailable. I will look at my mem usage to see what I'm using. I think I have the VM set at 4 gigs. I probably don't need that much.

[Digger[NJLP]]

Well if you do upgrade let us know how it goes with disabling the VM. You may have 4 gigs set aside for the page file, but the access time to the harddrive is alot slower then the access time to RAM. You may even want to try it before hand with the 2 Gigs to see what kind of problems pop up.

[Digger[NJLP]]

Its funny how this popped up on Digg about the same time Cupcake posted his questions.
http://www.codinghorror.com/blog/archives/000811.html

The only way to affectively use 4Gigs of Ram is with a 64bit OS.

As far as 32-bit Vista is concerned, the world ends at 4,096 megabytes. That's it. That's all there is. No más.

Addressing more than 4 GB of memory is possible in a 32-bit operating system, but it takes nasty hardware hacks like 36-bit PAE extensions in the CPU, together with nasty software hacks like the AWE API. Unless the application is specifically coded to be take advantage of these hacks, it's confined to 4 GB. Well, actually, it's stuck with even less-- 2 GB or 3 GB of virtual address space, at least on Windows.

OK, so we're limited to 4,096 megabytes of virtual address space on a 32-bit operating system. Could be worse.* We could be back in 16-bit land, where the world ended at 64 kilobytes. Brr. I'm getting the shakes just thinking about segments, and pointers of the near and far variety. Let us never speak of this again.

But back to our mystery. Where, exactly, did the other 642 megabytes of my memory go? Raymond Chen provides this clue:

In the absence of the /PAE switch, the Windows memory manager is limited to a 4 GB physical address space. Most of that address space is filled with RAM, but not all of it. Memory-mapped devices (such as your video card) will use some of that physical address space, as will the BIOS ROMs. After all the non-memory devices have had their say, there will be less than 4GB of address space available for RAM below the 4GB physical address boundary.

Ian Griffiths offers a more detailed explanation:

To address 4GB of memory you need 32 bits of address bus. (Assuming individual bytes are addressable.) This gives us a problem - the same problem that IBM faced when designing the original PC. You tend to want to have more than just memory in a computer - you need things like graphics cards and hard disks to be accessible to the computer in order for it to be able to use them. So just as the original PC had to carve up the 8086's 1MB addressing range into memory (640K) and 'other' (384K), the same problem exists today if you want to fit memory and devices into a 32-bit address range: not all of the available 4GB of address space can be given over to memory.

For a long time this wasn't a problem, because there was a whole 4GB of address space, so devices typically lurk up in the top 1GB of physical address space, leaving the bottom 3GB for memory. And 3GB should be enough for anyone, right?

So what actually happens if you go out and buy 4GB of memory for your PC? Well, it's just like the DOS days - there's a hole in your memory map for the IO. (Now it's only 25% of the total address space, but it's still a big hole.) So the bottom 3GB of your memory will be available, but there's an issue with that last 1GB.

And if you think devices can't possibly need that much memory-mapped IO, I have some sobering news for you: by this summer, you'll be able to buy video cards with 1 GB of video memory.

To be perfectly clear, this isn't a Windows problem-- it's an x86 hardware problem. The memory hole is quite literally invisible to the CPU, no matter what 32-bit operating system you choose. The following diagram from Intel illustrates just where the memory hole is:

[[FETT]Cupcake]

Cool find Digger...thanks.

Good thing I'm running XP Pro x64.

I'm not sure if I'm going to do it yet. I checked the task manager and I'm only running 1.2 gigs of memory with Company of heroes running. So I should be fine. I'll try turning off the page file one day and see what happens.

[Digger[NJLP]]

Crazy part was after the post I had this nagging in the back of my mind about 4 Gigs of Ram.

Then I saw the post on Digg and it all came crashing back from school.

Its a good read for those who remember the days of playing with emm386.sys and what not.