memory totals?

Hi,

Spec'ing some new systems and I have a question: I've found that
using sw64 in winxp64 I've never had sw consume more than around 3.2
gb of ram max. I'm curious about other peoples experience? The
question arose because it's possible to put 8gb of ram in a system (4
x 2gb sticks) but it's only available in slower pc-5300. My view is
it's better to save your money and buy 4gb (4 x 1gb sticks) of faster
pc-6400 (ddr2 800mhz). A penny for your thoughts!

Zander

 

If your datasets are large enough, SW64 will use more than 4GB RAM.

If you need more than 4GB RAM, you can probably configure a Xeon based
system for less than a comparable Core2 Duo. Definitely true of Dell
390/490 - harder to say with HP with their weird "Special Buy"
configurations.

In any event, there really isn't all that much dffierence between
667MHz and 553Mhz memory - only a few percentage points.

 

Hi,

That's interesting, I havn't priced any Xeon systems (although in my
rendering benchmarks the core2 duo's test faster) - I'll have to look
into that.

As far as large assemblies I've worked with upto 3 thousand parts and
stayed inside the 3gb barrier - I'm curious how many parts are
required to cause solidworks to go beyond 4gb? (obviously complexity
plays a big role here - but with so many parts hopefully the law of
averages comes into play)

Also, somewhere recently I read some benchmarks that showed upto 10%
difference between 667mhz ddr2 and 800mhz ddr2 although these weren't
solidworks benchmarks - I think they were game framerates. I'll have
to remember where I saw that article.

Thanks,

Zander

 

Remember the physical memory (RAM) is just a part of the total
(virtual) memory used by your system.
On 32bit machines, physical and virtual memory have the same 4Gb
limitation.
On 64bit machines, RAM can be viewed as just one layer of cache
between CPU register and a large virtal memory on hard disk, and the
role of the virtual memory manager is to keep in RAM only blocks of
memory that you access frequently, and to leave some available for
fast allocation.
Because of this Windows x64 tries to avoid allocating the full RAM
physical memory.
Right now I have 6Gb used with 4Gb RAM, but only 2.5Gb RAM are used.
If you want to force using RAM, you should disable virtual memory,
which might be a good idea on a machine with 8Gb or more. Did anyone
try ?

Philippe Guglielmetti

 

Also, somewhere recently I read some benchmarks that showed upto 10%

That may have been on Athlon/Opteron systems - or heavily overclocked
Intel systems. They are much more sensitive to memory speed. The
timings of the memory are critical, too. (Way too technical for
me.) With stock 533MHz and 667Mhz DIMMs, the timings are typically
better on the "slower" DIMMs, so in the end, there's little difference
in acual speed.

As for the Xeon/C2D - you're right: At any given clock speed, the C2D
is slightly faster than the Xeon. This is due to latencies in the
Fully Buffered memory used on the Xeons. Still, with more that 4GB
RAM, the price advantage of the Xeon outweighs the difference in
performance (at least with Dell and other custom configured
systems.)