Can a PC have a maximum amt. of RAM?

[Gusty987]

HP says that my 2-yr. old Pavilion 510C (currently with 256MB PC133 SDRAM) can only go up to 512MB (ie. another stick of 256). Does this make sense? Why the h*ll can't I just stick a 512MB stick in and have 768MB?

 

[ViRGE]

If it's based on the Intel i815 chipset(for the P3), then it only supports 512MB.

 

[Markfw]

Older PC's have limitations on what memory can be put in them. Forexample, some can't take double density or doubled sided,etc.. So yes, that can be correct.

New PC's are usually limited to 2-4 gig, and unless they are Athlon64 or Itanium, can only use 4 gig even for the server boxes. The Athlon64's go much higher (not sure the number, but my box can take up to 16 gig)

 

[Gusty987]

My HP has a Celeron 1.3GHz. Were those limited to 512MB?

 

[DaveSimmons]

It's not the CPU, it's the motherboard. Motherboards using the i815 chipset can only address 512 MB.

Try the memory selector at crucial.com to tell for sure how much your system supports.

 

[dullard]

Originally posted by: DaveSimmons
It's not the CPU, it's the motherboard. Motherboards using the i815 chipset can only address 512 MB.

Try the memory selector at crucial.com to tell for sure how much your system supports.

Exactly. Crucial.com also says your system is limited to 512 MB.

By the way, what would a 1.3 GHz Celeron need more than 512 MB for?

 

[CVSiN]

Um.. Most A64 motherboards on the market only do 3 gigs I Havent seen any over that so far.. maybe your opterons can do large amounts because its a server chip/board but the A64s do not..

 

[3chordcharlie]

A few manufacturers used to quote maximums based on the biggest dimms available (so I had a computer 'upgradable to 128mb' that actually could handle 256, but 128 dimms didn't exist when it was built).

I'd say it's not very hopeful that htis is the case for your machine though.

 

[3chordcharlie]

Originally posted by: CVSiN
Um.. Most A64 motherboards on the market only do 3 gigs I Havent seen any over that so far.. maybe your opterons can do large amounts because its a server chip/board but the A64s do not..

It's a chipset and/or number of dimm slot limitation for the A64 boards as far as I know. Not an inabiliyt of the chips themselves to address +4gig.

 

[Gusty987]

Originally posted by: DaveSimmons
Try the memory selector at crucial.com to tell for sure how much your system supports.

It gave me this:

# System Type: Desktop Computer
# Maximum memory: 512MB
# Standard memory: 256MB removable

Looks like I'm getting only 256MB more...darn.

 

[VirtualLarry]

Yeah, it all depends on the memory controller in the system. Usually that is part of the system chipset, but in the AMD64 chips it's in the CPU itself. There are other limits too, not on the absolute amount of installable memory, but on how much of that memory can be effectively cached by the L2 and sometimes L1 cache. That last issue really only affected Socket7 and older systems, most modern motherboards can cache all available memory. (Mostly because both the L1 and L2 caches are inside the CPU itself now.)

 

[imported_Kehcalop]

Most older computer do have a limit to how much ram they can read. This is usually listed somewhere in the manual. All 32bit processors have a physical limit of 4gigs because a 32bit processor can only address 2^32 memory spots. 4 gigs is more than enough at this time for nearly any computer user. most computer manufactures dont even offer enough slots to get up to 4 gigs. I beleive the largest ram they make is 1gig dimms. so you would need at least a motherboard with 4 dimm slots. The new 64bit processors have the potential to address up to 2^64 memory addresses. This is obviously way more than even double the memory. This wont be possible though until a 64bit operating system is available.

 

[Matthias99]

Originally posted by: Kehcalop
Most older computer do have a limit to how much ram they can read. This is usually listed somewhere in the manual. All 32bit processors have a physical limit of 4gigs because a 32bit processor can only address 2^32 memory spots. 4 gigs is more than enough at this time for nearly any computer user. most computer manufactures dont even offer enough slots to get up to 4 gigs. I beleive the largest ram they make is 1gig dimms. so you would need at least a motherboard with 4 dimm slots. The new 64bit processors have the potential to address up to 2^64 memory addresses. This is obviously way more than even double the memory. This wont be possible though until a 64bit operating system is available.

Two points:

1) Windows Advanced Server (and maybe later versions of Windows 2000 Server) can access more than 4GB of physical memory, but it's a painful process that applications must be specifically written for, and it involves software address translation (so it's slower).

2) I believe the x86-64 chips can only do 48-bit addressing, so the maximum memory is 2^48 bytes = 262,144 GB (that's 256TB). Not 2^64 bytes, but I think that'll last us a while. And you can get 64-bit Linux and Unix operating systems -- companies like IBM, SUN, and Alpha have been producing 64-bit CPUs for years.