no video memory & main memory are two completely different thing which don't add up.
- video memory is just for the graphic card and store what should be displayed on screen and other data which will be processed by the graphic card. (like textures for example)
-main memory is for everything else.
Yes.
This doesn't alter the fact that a 32-bit OS can only address 4GB of memory.
The problem is, many people take 'memory' to mean 'RAM'. When referring to the 4GB limit, 'memory' is the
total addressable memory space and not just the RAM installed. It’s a total made up of system RAM, graphics RAM, PCI memory range, ACPI and a few other bits and pieces. Every device on or plugged into the motherboard needs a memory addressable space in order to operate.
'Internet wisdom' seems to have created the myth that on a 32-bit OS, you can take that 4GB, subtract the amount of RAM on the graphics card, and that will give you RAM available for use. The problem is... it worked for some of the 256MB cards back when AGP was dominant - take 4GB, subtract 256MB, you end up with 3.75GB of usable RAM (I tried this with an Asus A8V board once). I don't know what tricks nVidia and ATi have used for being able to address gigabytes of memory on their cards without mapping each bit to the 32-bit total addressable memory space, but it's a neat one... the picture is further muddied by SLI and CrossFire, which seem to obey some dark rules that no one quite understands when it comes to treatment of addressable memory - since the contents of the VRAM is mirrored in each set of GPU memory... it
should on paper at least, be treated as one set of memory... almost like RAID1. For some reason... it isn't. I've not read enough about the technicalities of the two techs to know.
However, this is getting out of the remit of the original discussion and will result in technical details that will likely leave 2Air scratching his or her head even less certain of which choice s/he should be making with respect to Operating System. :)
if you really really don't want Windows se7en 64 bit then windows XP 64 bits is also an option.
Windows XP 64-bit is only an option if you want
a lot of headaches. Drivers for it are often few and far between (printers, scanners etc frequently don't have drivers) and those that do exist are flaky and some are missing features (I'm thinking of Creative here...)
I was running XP64 for a while for technical reasons... and if I could have got my hands on the source code for the program I was using and compiled it in 64-bit linux... I would have done. I have
never had any other incarnation of Windows give me that many headaches - even when I was looking after PCs running Windows ME.
In short, XP64 isn't really an option. There is no reason to avoid Windows 7 64-bit - I've been using it since public beta and it works great. Not found anything that doesn't like it yet. It's the first time I've ever installed an OS and not needed to install
one single driver. I updated the ATi drivers and installed Catalyst Control Centre (despite how much I dislike it...) but it wasn't necessary to do that to get games running happily.
