Uncreative Labs

Guest

I read somewhere that if you have a 64-Bit system running a 64-Bit Operating system and you have 512MB of installed RAM. It is the equivalent of having 256MB of RAM on a 32-Bit System. Is there any truth to this claim? Is there a link to website or article with information on this topic.

Any help would be appreciated.
Thanks.

Ki Mendrossen
A+ Certified Technician

Posted: Tue Jan 24, 2006 11:01 pm

I haven't seen anything like this, but I'd be willing to bet there's a small amount of truth to it. It may be it's like accessing that much RAM on a 32-bit system.

What's Ambassador Sarek need with 64-bit computers anyway? Or do you not yet work for him? (-;

Guest

Puckdropper wrote:

I haven't seen anything like this, but I'd be willing to bet there's a small amount of truth to it. It may be it's like accessing that much RAM on a 32-bit system.

What's Ambassador Sarek need with 64-bit computers anyway? Or do you not yet work for him? (-;

The ambassador's shuttle was caught in a temporal wake. I, the ambassader, and couple of aides were on board. We were transported to the 2005. We have worked very hard to create new lifes for ourselves until we can be rescued. The ambassador is working on a chrono-displacement device to transport us back to year 2369. Primitive 32-Bit personal computers are hardly capable of making the advanced sub-space trajectory calculations needed for the experiment to succeed. We need more advanced 64-Bit computers for any hope of success. The future of the Federation depends on our efforts.

Posted: Wed Jan 25, 2006 7:43 pm

You're breaking all kinds of temporal laws, aren't you? I mean, gmail now has a delete button!

I don't have a 64-bit machine to play with, so I'm going to be guessing/extrapolating from what I've learned from my classes. There's in one way no difference between 256 MB of RAM and 256 MB of RAM, irregardless of 32/64-bit machines. There's 2147483648 (2^31) bits in both cases.

Here's where the difference starts to come in. With a 32 bit word, there's 67108864 (2^26) possible words. Now, with a 64 bit word, there's half that number, or 2^25 for the same number of bits. If you're only using 32 bits of the 64 bit word, then you have effectively cut your memory capacity in half. The solution, of course, is to do better memory management. Write the code to take advantage of the larger word size, or figure out a way to encapsulate two 32-bit words into one 64-bit word.

Posted: Wed Jan 25, 2006 9:04 pm

Addressing efficiency decreases when using 64bit words the same way a 2gb hard drive had larger cluster sizes when using fat 16 than a 540mb drive using fat 16.

However running 32bit/64bit mixed programs the words would still be addressed in 32bit chunks (possibly 8bit chunks) meaning this isn't true yet.

Generally the most effective word size in terms of memory usuage is binary the more bits strung together the more wastefull as you are using 8 bits for example to describe something that could be described in a 1 bit word, a 2bit word, a 4bit word etc. But 8bit words have extra combos that cannot be described in a single 4bit word making them a wash on some instructions and on others excessive.

Cheers