hi,

i am using a ddr ram... and i am planning on making an upgrade (adding ram sticks)...

currently i have 2 strcks of 128mb ram. if i add another 256, i will now have 512...

now i am making a choice of whether to have this kind of setup or go for a single 512 stick

is there a performance difference "at any point" if i have 2 128mb and a single 256, or only a single 512 stick in my pc?

Shouldn't matter, as far as I know. If the RAM is all the same speed, then it doesn't make a difference.

Of course, if you buy a 512 stick, you can load it in there with whatever else you have, to get even more RAM.

It depends on what you're using it for. Depending on the amount of data being retrieved, and the size of the total memory (and the amount in use), more modules may actually be faster. In reality though, unless you are doing some pretty intense stuff (real-time and heavy duty serving, not gaming or other home PC intesive stuff, I mean), you won't notice a difference, as other factors (cpu and bus timing) play a much bigger role in this area.

I'd go for more memory, not worrying about speed, and let the cpu, motherboard, and OS decide how best to move data around on your system. Besides, why set those chips aside when you've already paid good money for them?

I don't think there's any way for multiple memory modules to be faster than a single memory module; the bus can still only carry so much data at a given time, and to my knowledge there is only one bus regardless of how many memory slots there are, so there is no way for them to work in parallel; the bus can only read/write data from one memory location at a time.

isn't it that if i have more memory sticks, power consumption increases?

well, its just an idea, since i add more devices unlike adding a single stick - more chips are present...

I don't know about DDR, since I'm still using SDRAM, but one of my machines (Athlon Classic 750 with VIA chipset) supports two-way memory interleaving. Basically it works like a two drive RAID 0 setup, addressing across the DIMMs. The modules have to be the same size and I can't use the third memory slot, but it does work. My mem read/write performance gain was only about 5-10% though. Here are a few google results on "memory interleaving" for you to peruse:
http://www.overclockers.com/tips105/index03.asp
http://macspeedzone.com/archive/5.0/...vedmemory.html
http://www.monitorworld.com/faq_pages/q36_page.html

my bios supports 4-way interleaving.. btw, my mobo is msi kt3 ultra2

But isn't the whole point of dual-channel DDR ram that the two simms do work in parallel? My machine listed below has a single 512 stick of PC3200 DDR ram in it and on boot it says 512 DDR operating in single channel mode.

I could be wrong but I think dual-channel DDR is the exception. SDRAM certainly cannot be run in parallel.

Interesting, I'd never heard anything about this. You're right, it does look like this is one way to get more performance by having multiple memory modules.

Hadn't heard about the interleaving thing either. Boy, you'd think they would have taught me this stuff in my six years of computer science courses... I guess I mostly learned the fundamentals, and wasn't brought up to speed on more modern technology

Anyway, I stand corrected.