I'm thinking of upgrading my p4-2800 512mb pc's memory. Since I am using one single 512mb memory now, updating to another 1G mem (2*512mb) makes me unable to achive Dual Channel Mode(MB is i865PE chipset).
Is it that important to get the dual channel mode as it would significantly boost memory's bandwidth? Also, my old mem is kinda low in spec. If I abandon it, I would get some tight timing new mem. In other words, is it better to have 1.5G slower single channel mem or 1G faster double channel mem? Any input is really appreciated.

whatcha doin with yur computer - what software/games are ya running?

btw always buy as much ram as you can afford, might not be a bad idea to solve your whole debate with 2x 1gig sticks if you can swing it

my system is a socket 754 - single channel memory only, i'll tell ya i dont notice any huge memory latency issues

i would even be willing to bet you wont, unless you are right on the edge of "desired preformance needed for some FPS game" where a lil extra would help you from droping frames durring a big fight or whatever

anyhow thats my $0.02

Thanks for the reply.

I use it mainly for games like civ4, HOMM5 and would like to try Oblivion after I update my Video card to 7800GS.

I saw some test results about Dual Channel Modes around the Internet, but not in THG. It seems nice on paper: 2x memory bandwidth. But I have no idea about the actual game FPS improvement.

Ok what?
You have a single 512MB. That means you don't have dual channel at all. You can't have dual channel w/ 1 memory module!
I'd go w/ dual channel over single. I think timings vs dual channel, dual channel will give you more. I think dual channel is something like max 10% improvement.

Nobly, i do believe is pretty accurate here. What the "paper" tells us is 2x memory bandwidth, what the reality is, in real life benchmarks the performance increase in apps and games is only around 10%. If i can remember properly, it's not even 10 in some apps,games so mabey 10% +/-5%. I can say with a fair amount of certainty that if you want to run oblivion, get a crap load of ram. I think that game benefits from 2gig, some one please correct me if i am wrong.

I wont sit here and and say this is all fact, but i've seen a few benchmarks "dual channel vrs single. I was not impressed at all. Wish i had a few links to toss at you. If you want to look up socket 754 vrs socket 939 performance in the CPU charts, MHZ for MHZ the socket 939 (which has dual channel memory, 754 does not) just isn't that much greater than socket 754.

I'm sorta on the same page as Nobly here, if you can, by all means go with dual channel, more performance = better, regardless. Just don't get your expectations to high, cuzz the performance isn't.

more memory

after doing the compair myself ....

on an AMD settup - looking at slightly older processors of course

try this out yourself if ya wanna

i picked out 2 1800mhz processors in the interactive CPU charts
3000+ Athlon 64 Venice (socket 939 dual channel RAM)
2800+ Athlon 64 Newcastle (Socket 754 single channel RAM)

the performance difference almost is not there, in fact ill bet the socket 754 performance numbers could have been a tad bit higher than the socket939 if a different motherboard was used, who knows....

still doesn't paint an completely acurate picture of how Intel CPUs would perform in single or dual channel. But i think its at least indicative....

i would say, for you, your best bet is just to try and get as much memory as you can if you want to attempt higher end games.

my $0.02

i agree more is better <preferably matching>

Correct answer: sell your current 512MB on eBay and buy 2x1GB.

Agree, if it fits into your budget. I was poking around newegg and 2x1GB DDR400's are about 190-220.

Or another possibility is to just get another 512MB module and get dual channel. And then just see if you need more later, then you can go and get 2x512 or 2x1GB. (Assuming you have 4 RAM slots of course).

Oblivion is the highest requirement game in your list, so its

So that means it's probably going to need more than 1GB... heh.