I'm following with interest your question.
I have an I7 920 with 6 GB of RAM memory (3x2GB DIMMs) and I never saw more than 50% of memory used. Only with the OS and its processes working, about 2GB of RAM are used. I don’t know yet why, but I give responsibility to the actual software. I work with ADOBE applications, and even with PHOTOSHOP CS4 64 bits I don’t see more memory used. Even with several ADOBE applications working with heavy documents, internet in use, Outlook connected, and so on. And even the processor is only used at 17%. And me too, I should like to understand why. Problem of CPU or problem with Operating System, which in my case is Windows 7.
For instance with Illustrator CS4 where I have some heavy applications, taking a long time on rendering and shadowing, in my laptop, one Pentium at 3,2 GHz Multithreading with 2 GB of RAM with 6 years, I had best performance than I have now.
I am looking for the answer to your question and with this post I intend to enforce your doubt.
The codes in question are fortran codes compiled using intel's compiler; thought, the same issues are prevalent with Matlab, Feko, etc ( all codes work well on 64 bit systems- except i-x based ones). The codes work wonderfully on any cpu with any operating system except for the i-X architecture.
I have tested this on :
Windows 7, Windows 64 xp, windows xp in single threaded and multi threaded forms
I have tested the windows 7 + i-X combo on:
Asus, samsung, dell, sony and Hp (all behave poorly)
I have tested the windows 7 + non i-x combo on
pentium, core 2 and AMD processors (all preformed perfect)
I have run the codes on 4 different Dell Xeon cpus (all less than 1yr old) with Xp64 and windows 7 and they all execute the code using all 8 cores at 100% usage
The only thing that I have left to do is to install linux on my laptop and see the performance
if it isnt 100% then it is clear it is entirely a intel i-x problem (intentiona or unintentional)
If the problem is rectified ( ie 100% cpu usage) then it is a windows7 + i-x problem
Hopefully the right person sees this and can help
Try to go to Futuremark and there to PCMark. You are only allowed to make one checkup or then buy the application. It is fery useful so that you can see trhe performance of the various hardaware components of your computer and compare with similar ones. I bought it. With that application and with task manager oppened in the second monitor I could see my I7 fly until 50, 75 and even to 100 % for several times. Finally, yesterday I had to convert the format of several files of about 1 GB each. I solved to do them all at the same time, but iniciating one by one. And my I7 began with thw eternal 17% and some time after if was above the 75%. I took little more time for all the files (I think about 7) than for only one isolated.
So, I think taht your problem, like mine is that your software is not develloped for INTEL 64 and IA 32 Architectures. Try to go to INTEL site and read a little bit of the first volume in the developpers center for programmers http://www.intel.com/design/corei7/documentation.htm