What's your memory assessment speed?

Okay i am back to report how it works with 4Gb instead of 2Gb, here are the results of the winsat mem test 'before' and 'after':

RAM frequency = 400Mhz (1:1), 5-5-5-18, 1.8v:

With 2Gb: 4800Mb/s
With 4Gb: 7200Mb/s

RAM frequency = 533Mhz (3:4), 5-6-6-16, 2.1v:

With 2Gb: 6400Mb/s
With 4Gb: 8000Mb/s

We have our answer cabal06ca! Indeed the quantity of installed RAM plays a great role on the overall performance :)
It seems quite logical since you have 8Gb and get more than 16000Mb/s! But the problem is that I do not multiply by two my old score (with 2Gb)... There must be an issue, probably with the quality of the Motherboard, actually mine is not a good horse at all so it may explain that sum.

Your results are good, don't worry about it anymore!

Sounds difficult when you are a perfectionist like I am ^^

Anyway, I am glad to hear that my system is running fine and without important issues. Last question: according to you should I stay at 400Mhz or continue in the Enhanced Performance Profile which is 533Mhz and means the higher voltage for the modules? Should I worry about that or let it go too?

PS: WEI RAM score before: 5.5
WEI RAM score after: 7.0 !!

You are certainly right, I'll let the settings like that (till the next crash, what I'd prefer avoid ^^).
Perhaps change just the timing and see wheither lower values may work; however 5-6-6-16 2.1v are the recommended ones in EPP and show an increase of more than 10% campared to the 1:1 400Mhz 'simple' mode.

I can feel that I will have a good rest after all these frivolities

I had tried to run Memtest86+ with a bootable USB key but failed...
Now I try with a floppy (unforgetable piece of plastic!), I will post the results as soon as I get them :)

If you install two RAM modules of the same size and speed in a dual-channel configuration (it gets enabled automatically by 90% of motherboards), then you effectively double the available bandwidth from your memory controller to the RAM modules themselves

CPU-Z tells me that the two modules actually work in dual channel, however I do not double my score with 4Gb DC instead of 2Gb SC.. Could it be a problem or is it normal as cabal06ca said?

However I found it when I was reading the wiki link you gave me:

Tom's Hardware found little significant difference between single-channel and dual-channel configurations in synthetic and gaming benchmarks (using a "modern" system setup). In their tests, dual channel gave at best a 5% speed increase in memory-intensive tasks.

Hopefully for me the gain is quite higher than 5%! I know there is nothing else to do for now but I cannot be 100% satisfied with my score...
I've also read (I have got big ears) that the difference between the performance you can get with DDR2 and DDR3 are very small but wheither it is wrong, means that DRR3 would be much more efficient than its old brother, then I'd understand certain values some people here manage to get with their 8Gb DDR3 modules.

No need to post any results, this program is quite simple:
When you wake up and see lots of 'red' on your screen, you (might) have a problem, if there's no red you're good to go!

I get a nice error when I try to run Memtest86+ in order to make a floppy, even if I already read almost everything about it: the program does not recognize the files in the 'boot' folder (I run Install64 though...). I will retry later.

I've been reading through your posts starting on the previous page here, very interesting read actually

Thank you!
Actually I think it can be useful for other people on this board (and not only btw) to know how all of that works :)