Best Memory (DDR2 SDRAM) Configuration

You mean 2x 2GB ?

Another option I suppose would be to use the 2GB Corsair until the other RAM comes back in stock and I place my next bulk order ...

PUNKY, do you mean I can still utilize dual-channel as long as I have 2 matching pairs - even if the the 2 pairs are different?

Careful with term of dual channel:
http://www.crucial.com/kb/answer.aspx?qid=3751
Yes, you can use 2 differ pairs on this board.

okey the problem here is that windows xp (32bits) can not access 4gb. It only can acces like 3.2 o 2.6 gbs depending on your config

Also, check board manual, the information is all there. I have same board with you (several of them), and I dont see any differ performance either mixed or matched memory (all running XP 32 bits) ... and my users are free to configure memory their own way ...

I know about the 32-bit restrictions but as I understand it, having 4GB installed is still better than having 3GB installed. I'm not an expert on this but according to Microsoft the limit in Win XP 32-bit is 4GB. As I was told, 1GB would be reserved for system devices, 1GB utilized by Windows and 2GB for applications.

I presume the differences between CL4 and CL5 memory would not be noticeable?

*** differences between CL4 and CL5 memory would not be noticeable?***
If you do overclocking you might see differences but I never try so.

Thanks for all the help!

PUNKY, one quick (off-topic) question, since you also seem to use ASUS boards: are all of ASUS' newer models Vista-ready? I used to see it mentioned under the specs but don't anymore. I presume they would be...

just a side note:
if you are going to use ram with different CAS timings, I would either put the slowest pair in channel 1 so the bios will use that SDP info, or set the timings manually, to keep the faster pair from trying to run the slower ones at a rating they will not like.

>> the system will use the SPD info from the slowest module regardless.

Sweet. The bioses got smarter since the last time I tried that.   : )

Thanks for all the help. One last question:

Can I use any DDR2 SDRAM 240-pin non-ECC RAM in this board or is it advisable to stick with memory suggested by the RAM manufacturer's memory configurators?

I ask this because I've been looking at the Kingston ValueRam and Kingston HyperX configurators and none of the modules seem to be in stock. However, when I do a manual search on my suppliers interface I get the following option:

KVR800D2N5/2G - Memory/2GB 800MHz DDR2 Non-ECC CL5 DIMM
KVR800D2N5K2/4G - Memory/4GB 800MHz DDR2 Non-ECC CL5 DIMM (Kit of 2)

But when I check the KingstonVR configurator these aren't listed - all the 800MHz modules listed are CL6, which is the only difference I can see.

Also with the HyperX memory, I found this one:

Memory/4GB 1066MHz DDR2 Non-ECC CL7 (7-7-7-20) DIMM (Kit of 2)

Which is not listed on the HyperX configurator (all the modules listed are 800MHz).

KHX8500AD2K2/4G - Memory/4GB 1066MHz DDR2 Non-ECC CL7 (7-7-7-20) DIMM (Kit of 2)

Either of the above should work fine.  The only possible "glitch" is that the 2.0v module may require an adjustment in the BIOS to set the higher voltage (the DDR2 standard is 1.8v) ... but most boards will automatically set this.

Are they not both 1.8v ? I thought I saw it in their spec sheets ...

The last one (the 1066Mhz) is a 2.0v module.

Ok, I just saw it on the product summary page. But on the spec sheet it says +1.8V (+/- .1V)
Timing Reference: 6-6-6-18 at +1.8V / 7-7-7-20 at +1.85 to +2.0V

http://www.valueram.com/datasheets/KHX8500AD2K2_4G.pdf

By the way: which one of thos would you recommend. I presume the HyperX one?

Thanks for all the help and info! I got 3.25 GB of useable memory so am happy enough. The Intel E8500 is running well by the way, garycase, so thanks again for that too :)