[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: What to choose for Core i5 64 bits?

> The 64-bit vs 32-bit argument is multi-faceted.  It gets much deeper than
> just addressing more than 3GB of RAM:
> * twice the transfer width on the bus

Nope, no difference on the bus.   Most accesses will be
cache-line-sized anyway at that level.

> * no memory split issues

For <=3GB systems, that makes no difference.  And as someone running
a bigmem kernel on a 4GB system, I can say that even for other systems,
it's not necessarily relevant.

> * increased virtual address space

Right.  Unlikely he'll ever notice it.

> * more breathing room for mmap()'d files

Again, unlikely he'll ever notice it (otherwise he wouldn't have asked).

> * deeper nested system calls with increased stability

I see no evidence of increased stability and have no idea what you want
to say with "deeper nested system calls".

> * certain applications and operations will execute faster

Yup.  And others will be slower since you'll have to move around more
data (up to twice as much if your data is made up mostly of pointers),
which means that the apparent cache and RAM size will end up
being reduced.

> If you have the hardware, you should definitely be running a 64-bit
> operating system, even if you don't have 4GB+ of RAM.

If you have to ask, you probably won't notice any difference
either way.


Reply to: