i7 Vostro 430, DDR3 single channel/dual channel question

With the modules you have - a 2GB and a 1GB -  you are running in single channel.    Looks like on your 430 the slots are colored blue and black (link below), so to use dual-channel,  you'd need to install matched pairs of modules in the blue and/or black slots.     Matched pair means just that - the modules have to be identical in size, speed, and configuration, so 2GB and 1GB aren't a matched pair.

If you had 6 slots, triple channel would require 3 matched modules.   It would still revert to dual or single depending on what modules you installed where.

However, whether single channel is really a "bottleneck" or not is debatable.  The original idea behind dual channel (and now triple channel) was that the memory controller couldn't keep up with the processor, so if you paired 2 modules together you could access memory  faster, much like the difference between a 2-lane and a 4-lane highway.   But memory usage is not some fixed number - it depends entirely on how you use the PC.   CAD and gaming are CPU and memory hogs, emails and surfing are not.     Going to dual-channel certainly won't hurt, but if you'd actually notice the difference depends on how you use the PC.

And yes,  Win7 32-bit it won't be able to directly use a full 4GB of memory.   How much will actually show up as available for use  depends on how much memory is shared with other things like video cards, etc.   It ranges from 3.5GB on down, depending on how the system allocates memory to other hardware.  

cheers for that Alexandra_P

Well im using the PC for 3dsmax, CAD and Photoshop work mainly which is why i had concerns, what do you think?.  However this clears things up a lot thanks. its just good to know i can upgrade appropriately in the future and get the most out of the CPU and other components. ive just upgraded from ancient 2.5GHz p4, Geforce 5500 AGP, so all this stuff is new to me. 

apparently the Graphics card with these machines are'nt great for 3d work(512mb Radeon HD 4350 DVI HDMI), more for HD and multiple display. so i'm gonna stick a 1GB 9800GT in their with a beefier PSU eventually.

I wouldn't worry much until you actually play with it a while.   Probably the video card would be my first choice for an upgrade - but if you're accustomed to an older PC,  you might be more than happy with it as-is.   I leapfrogged the technology even further a couple years ago, and it was like night and day.   Of course, now I'm way behind again.  :emotion-4:

Might be a good idea to check with other 3dsmax and CAD users on whether having the 2GB/1GB memory is a big deal or not - my understanding is any one process can't use more than 2GB anyway, but don't quote me on that.

Anyways, good luck with your new system.