Dual channel RAM

[hambone2]

I am thinking about getting 2 PC3200 DDR 400's at 512 a piece, totaling at 1 gig of memory

However...I have a PC2700 I COULD add on making it a gig and a half...would I lose the Dual CHannel and 400 Mhz capablities if I did that? But still have a gig and a half?

[Dr.Gibbs]

Do you need a gig and a half? It will slow it down if you add it. You'd have to check with your motherboard manual to see what kind of configurations are supported by dual channel mode. A lot of times you can have two modules together and then a third. But your entire bus will be 166MHz instead of 200MHz.

[Tyranny]SiN[]

I stand corrected by DocJ. I apologized for my knowledge of dual channel operation as well as Ideal standard of ram capacity per individual.

[hambone2]

Actually, to be more precies..I have a Hi End ASUS board..don't know the exact model...it's NOT the deluxe, its like A87NX? (Letters perhaps not in that order)

It has the Nforce Technology and is Dual Channel Capable.

Currently, I have a 512 PC 2700 (333Mhz) chip.

I want to buy the DUAL 2x512 (2-chips) at half a gig a piece. PC 3200 (400Mhz)

Would I Need to take out the PC2700, and replace it with BOTH NEW chips...it would THEN run at high capacity....

NOW...next step IF and ONLY IF, I decide to ADD that old PC 2700 Chip...would it SLOW it down or SPEED it up?

(Totalling 1.5 gigs)

[Daneph2]

assuming that MB runs at 800mhz...


use the 2x512 and lose the 2700, it will slow it down, I highly doubt you need more than 1Gig anyway.

[DrMDJ]

Running dual channel or not, if you mix PC3200 dram with PC2700 dram then all the ram will (as Dr. Gibbs said) run at the lowest common denominator speed (in this case pc2700). So if you really want the DDR400 speed you will need to remove the PC2700 dram you have now.

the point of the dually's running at 400mhz a piece is to run them both at 400x2 to give it a 800Mhz increase.

Actually that is neither the point or the effect of running a dual channel memory configuration. Running dual channel does not increase the bandwidth of each channel (each would still run at an effective rate of 400mhz here). Nor is there a combining of the individual bandwidths of each channel in to what would be equivalent to an an 800mhz effective bandwidth. The actual/real benefit of dual channel is no wheres even close to what a true doubling of available memory bandwidth would acheive. What dual channel does do is allow certain memory operations to overlap and happen simultaneously. Essentially it allows a memory read operations to be occurring on one memory channel at the same time the setup for another memory read (not a read, just the operation to setup a memory read) is occurring on the other memory channel. Normally (in single channel mode) these two operations would need to be queued and happen in a single-threaded fashion. There is a benefit to the dual-channel opertaion, but it is not a doubling of memory performance. The "real world" benefit is like 15% at best, and more likely in the realm of maybe half this. That's not to say it is worthless, just not as big a deal as one might think.

I can't say offhand what the specific requirements for your particular motherboard are when it comes to running in dual channel mode. On some boards you can actually have (the boards will force) a mixed operation with some of the memory operating in dual channel mode while some operates in only single channel. Not something one really wants, but... In other cases either the requirements for dual channel operations have to be met exactly or none of the memory operates in dual channel mode. So things like what memory you have in what slots, what the stick sizes are, etc can effect how things operate and whether or not dual channel is used.

One and a half gigs of ram is a lot, more than most people really need and can benefit from. There's no way to say offhand whether it will benfit you. And it certainly can't be said that is an "ideal" amount for you (and the ideal for anyone isn't based on the total amount of ram the motherboard can handle anyway). What the benefit (or not) will be to you depends on the demands of the application mix you run. By the way... You actually can have too much ram in certain cases, and there have been tests that showed where having more than a gig of ram (with XP) did have a negative effect on performance, in certain cases, with certain boards. This is not to say this is a given or that it will be the case with you, just something to keep in the back of your head. It's been said "you can never have enough ram". Well, that is not always true.

One final note... If your processor runs with a 166mhz bus speed then going to pc3200 (ddr400) memory may not be benefial (relative to using PC2700/DDR333). Often better performance is had when the memory bus and the processor bus speeds are in sync. So in the case of a processor using a 166mhz fsb it can be best to run it with memory using a memory bus speed of 166mhz (ie. PC2700). Running with memory that operates at a higher bus speed can actually introduce latency issues that hurt overall performance. Just a point to consider.

[hambone2]

Oh, CRIPES!

Yeah...a year ago, when I initially upgraded motherboards, I upgraded to that ASUS board...but guess what, during that time I had the option to purchase either the ATHLON 2800+ 333Mhz, OR the Athlon 2800+ 400MHZ....yeah, you guessed it, I got hte 333Mhz, so I shafted myself, for not "Thinking ahead".

So I guess I'm stuck at the PC2700 option, cheaper though, but I can go up to 3 gigs of RAM on my ASUS board hte board IS 400Mhz capable though.

I am an avid gamer...I play games like Half Life 2, Doom 3, Splinter Cell and other Tom Clancy Type games

Doom 3 and HL 2 is really state of the art Graphically intense software. I Currently have half a gig of ram only, and a friend of mine told me a half gig (for games) don't really cut it much these days.

Esp after the Level Loads, and after its done loading, there's like 4 to 5 seconds of choppiness, then it smoothes out...probably due to RAM? (Only min requirements)

[SuperSparks]

If I were you, I'd add a second 512 stick of PC2700. You really don't need more that 1GB of RAM for gaming, or much else either. I have 1GB of RAM, and my experience is that the pagefile is never used even with many apps open at the same time, so there would be no advantage at all in adding more, and as the Doc said, it could even make things worse.

[DrMDJ]

I'd agree with SS. Go up to 1gb of the PC2700. Run in in dual channel mode (to get that benefit). You should be fine.