Will 64-Bit XP Recognize 4gb of RAM?

Hey, I'm looking to buy a notebook, but I am not sure if 64-bit Windows XP will recognize, and be able to make use of, 4 gigabytes of dual-channel memory. I know 64-bit Vista can do it, but I would like to use XP.

?

 

Yes, Windows XP x64 will support 4 GB of RAM. Quoted directly from Microsoft:

 

I find it kinda funny how 32-bit struggles to get more than 3 gigs of ram addressed, while 64-bit over here is using up to 128 gigs.

 

Evolving technology, my friend. When 32bit debuted, 4GB seems like a huge amount. Most Windows 95 computer ship with around 32MB of RAM, which 95 finds it more than enough.

 

I am not good at math but here goes, what I think is throwing you is you are thinking 64 is only twice 32? but mathematically it is actually 2 to the power of 64 and 2 to the power of 32 respectively (2 because computers binary, base 2). I'll do base 10 cause for us normal guys more how we think, 10 to the power of 2 and 10 to the power of 4 respectively 10X10=100, 10X10X10X10=10,000 clearly more than double. That is how the number thing works, trust me the numbers add up to the diff between 32 and 64, how addressing memory and registers and what it really means I lack the education.

32 bit can address 4GB but for some reason Windows only 3GB I hear.

Had to write out "to the power of" because numbers would not display correct any help?

 

The same reason why we had only 640K back in the DOS days.

 

please explain I'm not a dos baby started on 98

 

The upper 1G(like the upper 384K in the 8086 days) have been used to map to all sort of thing. Nowadays, it is usually the GPU memory address space take the bulk of it. So there are lots of holes in the upper 1G.

As a result, microsoft just say, we would only use up to 3.2G in 32 bit mode. Now 64-bit actually use the same scheme but the upper 1G of 64 bit addressing is not something I would worry(too many zeros).

Now the only thing I am not sure is that if I use a shared memory GPU, would I be able to use the 4G more effectively. That is, the upper 1G is already reserved for them, just use that part for the share memory GPU space. If that is the case, a populared 4G system may have only about 500M wasted, if I have a 512M shared memory GPU, instead of 800M.

 

Would not recommend XP 64bit. If you are desperate to use a full 4GB complement, go with Vista x64.

 

Why would you not recommend it ?

I don't know alot about x64 XP but i've gotten myself a copy in order to get use out of my RAM.

 

If it works it works. If you want to use 4GB of RAM and want Vista go with x64. If not, stick with XP.

 

yep, thats ok. but there are some downsides with xp 64 too.

You will be able to use the 4GB. thats not the problem. but if you want to use the hibernation ( powersaving) xp64 won´t let you unless you limit the adress space yourself.

you will have to use a 4GB switch on your kernel during startup, that limits the system meory to 4GB of physical adresses to get the hibernation to work.

these 4GB include graphics ram / network adresses......

when you want the hibernation option you will not have more than the typical 3-3.2GB of ram that you will get with a 32bit windows.

i made two start-options for my xp64 - one with the full 4GB ( for rendering etc...) and another one with the 4GB switch that i use most of the time when i´m not rendering. this will allow me to at least choose what feature i need most at that moment.

 

Hibernation means 2GB of wasted HDD space to me (it takes exactly as how much you have installed), so I have never tried it.

 

you may not have found the use for it... but i can assure you there is a lot of sense in this powersaving scheme.

i´m driving a lot by train and i do work in the train. if i stay with the rendering example.... when i´m rendering and i have to leave the train i just can put the laptop into hibernation.

when i´m at work i just push the power button, and the system comes back to state it was when i shut it off.
and the rendering i started will be resumed. this saves a lot of time, since i don´t have to restart the whole rendering.

i´m very pleased to have this feature, and i certainly don´t miss these 3GB on my hdd.

;-)

 

The reason is simple.
a 32-bit system uses 32-bit addresses. If an address is 32 bits long, that means there are 2^32 possible addresses, or just over 4 billion. (4 * 10^9)
4 billion bytes = 4 gigabytes. And for various reasons, a certain amount of this (often around 800mb) has to be used by the OS for housekeeping. That leaves roughly 3.2GB as memory addresses.

64 bit: Memory addresses are 64-bit, that means there are 2^64 possible addresses or something like 16 * 10^18, or four billion times as much as you have with 32-bit.

Again, Windows takes 800MB (ish) for housekeeping, which leaves you with.... still vastly more than you're ever going to need.

As for XP64, it worked fine for me when I used it.

 

It actually is alot more than 128gb.

It's in the millions of gb's of ram. Vista artificulary limits to 128gb.

 

Kind of a late ressurrection for this thread! In general mods prefer one not to bring back these old dead threads here.

 

Necrothreading should be a bannable offense.

 

nope, old thread should just get autoclosed (and if one wants to reply, auto-create-new-thread-with-quoting-of-the-original-incl.-link .. )