HP ProLiant DL380 with 12 GB Ram?

[Michael Hachen]

Hi NG!

OK, this is probably not the right forum to ask this question but someone might have an answer to my question!

I'm a student of applied computer science and at university we talked about memory management / paging and virtual memory some days ago.

Now, a HP ProLiant DL380 has only 2 processors so the maximum available address-space is 2 x 32 bit = 8 GB physical addressable memory. But on http://h18004.www1.hp.com/products/servers/platforms/index-dl.html you can see that the maximum memory is 12 GB?!
Does anybody know what kind of technique HP uses to address 12 GB? (I'm not a spy, just a snoopy student!;)

Many thanks for this information!

Mike

[Ruslan · Accepted solution]

Hi Mike!

The widths of the address bus and maximum addressable memory for the Intel processor family are listed in the following table.

Processor
Address Lines (Bits)
Theoretical Maximum Addressable Memory

8086
20
1MB

80286
24
16MB

80386 and 80486
32
4GB

Pentium
32
4GB

Pentium Pro
36
64GB

Pentium II, III, and 4
36
64GB

Pentium II Xeon and III Xeon
36
64GB

Xeon
36
64GB

Itanium
64
2^64 GB


Note

The ability of the processor to access the maximum address space can be restricted by the chipsets and the operating system.

[Michael Hachen]

Hi Ruslan

Thank you for your answer!

Wow, I always thought that Pentium IV or Xenon are 32-bit Processorc and that they have a 32-bit addressbus...

But not at all! That's good to know, some of my professors will surley look surprised;)

Again, thank you!

cya Mike

[Basil Vizgin]

This 36 bit of addresable memory enabled on 32-bit platforms by Intel PAE (Physical Address Extension).
Read this, for instance:
http://www.cs.wisc.edu/~remzi/Classes/537/Fall2005/Lectures/lecture14.ppt