RJK said:
...am sOOooo rusty.
Aunty's PC has a Skt. AM2 Asrock AliveNF6P-VSTA motherboard in it with
single core 3800+ 2.4ghz cpu,
and 2 x 512mb's PC2-5300 ((166 actual?) / 333 mhz)
..and I just nabbed her a
AMD Athon 64 x2 CPU 5600+ (ADA5600IAA6CZ) (2800mhz) AM2, on ebay.
I gather that to have the thing operating at its' best, we would fit
PC2-6400 memory modules - whch would run at 200mhz on the board, before
double-data rate and fsb/cpu core internal quad-pumping etc. confusing
considerations !
And I gather that if I fit the dual core chip which supports
1066*/800/667/533 fsb frequencies, the board fsb actual freq. will be 166
mhz using PC2-5300 modules.
So would it pay to buy new PC2-6400 (200mhz) memory modules, or will it be
satisfactory, performance wise, to leave the PC2-5300 in there, and avoid
the cost of replacing it ?
TIA
regards, Richard
1) The memory controller is on the processor.
2) The memory clock is synthesized by the processor. The value it uses, is
selected to not exceed the module rating. The core clock is divided down
to make a signal suitable for driving the module. Since the divider has
limited resolution (it is very coarse), depending on your processor,
it may not be able to make precisely the correct clock value. It will
make the "next lowest" clock value, if that is the case. I think both
your old processor and the new one, don't have that problem.
3) There is no "quad pumping" on AMD. That is an Intel terminology, related
to the externally visible FSB. On AMD, the equivalent of the FSB, is inside
the processor. There is probably a web page somewhere, that discusses
whether there are bottlenecks inside the processor itself. On AMD, the
external bus is HyperTransport, which uses a smaller number of higher speed
signals, to communicate to the Northbridge and its PCI Express video card slot.
As far as I know, you could leave the memory there, install the new processor
and it would work.
As far as a "trigger" for changing the memory, carry out the following test
before disassembling the system.
1) Run Prime95 in Torture Test mode. Does it run for hours without reporting
errors ? If no errors are found, your existing RAM could still be error free.
If the memory shows errors, and especially if you can find stuck-at faults
with something like a memtest86+ floppy, then go shopping for new memory.
Memory fails often enough, that memory errors provide a better reason to
spend money on new modules, than just making speed changes.
If the existing memory is running well, just plug in the new processor and
use it.
The main benefit of a dual core processor, as a replacement for a
single core processor, is smoother desktop operation. Single core processors
don't seem to operate as smoothly, in my testing here. So that would be the
most visible benefit. If Aunty uses Photoshop, that might run faster with
the new processor. Or even web browsing could be faster.
Generally speaking, buying expensive boutique memory is a poorer investment,
than getting a faster processor. Memory speed changes add a few percentage
points to overall performance. You need a pathological case such as WinRAR
compression or Photoshop, to get a little more benefit from faster memory.
But for balanced desktop operation (a little of every kind of application),
it isn't worth the bother of changing it. Aunty would likely not
be able to tell the difference, if you did a blind test and installed
either the old memory, or your new boutique memory. If all Aunty does,
is run memory bandwidth benchmarks all day long, then naturally she would
want "only the best" memory for that.
Paul
