The exact difference between 32 and 64 bit.

**Mcstrange** · 02-20-09, 09:37 AM

64 bit can theoretically access up to 128 gig of memory, but you run into a hardware limit around 16gig in most consumer level hardware.

**Manse** · 02-20-09, 10:14 AM

Originally Posted by Mcstrange

64 bit can theoretically access up to 128 gig of memory, but you run into a hardware limit around 16gig in most consumer level hardware.

Hell, even in workstations, that'd be a bitch to get up that high

**Imisnew2** · 02-20-09, 02:10 PM

Originally Posted by Mcstrange

64 bit can theoretically access up to 128 gig of memory, but you run into a hardware limit around 16gig in most consumer level hardware.

Hardware limit?

**Mcstrange** · 02-20-09, 02:39 PM

I am not aware of any motherboards for desktop PCs that support more than 16gb, and most of them support less.

Past that there is the cost issue. Its very expensive to buy more than a 4gb stick of memory. I think going up to an 8 gig stick increases the cost by a factor or 8 or 10, and getting more than 8 gig on a single stick of ram is not possible on the consumer market.

So with current hardware a normal PC builder would not realistically be able to put more than 16gb in a pc.

**Imisnew2** · 02-20-09, 02:42 PM

So... you could get 4 sticks of 4gb.

someone said on 32bit you could only have 4? I don't understand why 64 bit could hold 128gig but 32bit only 4? Why not optimize the freakins stuff you make it instead of creating restrictions on the stuff.

**Mcstrange** · 02-20-09, 02:59 PM

Its math imisnew. Its not an artificially imposed restriction, its a mathematical restriction. Check the wiki link I stuck up earlier and do some google searches if you want to get the exact science behind the various bits, its fairly involved and not only comes down to math, it comes down to how small things can be manufactured and how smart someone creating something like a microprocessor is..

**Imisnew2** · 02-20-09, 04:26 PM

ok so basically

232 = 4GB addresses. Which makes 4GB of memory possible.
264 = 8ExoB addresses.  Which makes 17.2 billion GB of memory possible.

BUT

Because hardware has certain limits, a bottle neck, that limits the total address length to be - i.e. 32-48bits - we cant access more memory than is possible. (248 = 28.15 thousand GB).

And since memory really doesnt exceed 4GB per stick in the consumer market, our only restriction is the amount of memory we can fit onto one motherboard (assuming the Motherboard has something > 32bit bottleneck).

That's what I got from the wiki page.