Corsair PC2 8888, 3GB possible?

[joejones]

I'm relatively new to high end PCs, but I just bought a new system.
I've been doing a lot of research and come to the conclusion that RAM is very confusing.

To start, my system:
eVGA 680i SLI nForce
Extreme QX6700 Quad
Dual 768MB NVIDIA 8800GTX
Corsair PC2 8888 RAM 2 GB
http://www.newegg.com/Product/Product.asp?Item=N82E16820145044
Windows Vista 32bit Premium

I, as others have suggested, would like to optimize my performance by going to 4 GB for extreme gaming. As has been stated many times before, using 4 DIMMs reduces performance and therefore the true benefits of the PC 8888 would never be realized.

Here are my questions:
(1) I know 32 bit is limited to 3.2 GB seen at any one time. I know that the PC 8888 comes as a pair of 1 GB RAM, but what if you only used 3 x 1GB of the RAM at once. You would not be using 4 DIMMs and therefore shouldn't take the performance hit. would would the clock speed be then? I would waste 1 GB, but maybe it could just be split with someone else in a similar situation.
(2) I was also hoping someone could better explain what exactly happens when you use 4 DIMMs. I have read that a MB will drop the clock speed to 667MHz automatically. Would it matter if you started at 1111MHz or 800MHz? Is it a relative drop or an absolute drop in clock speed? Would they both clock down to 667MHz just the same?
(3) I also read that with 4 DIMMs your rate command drops from 1T to 2T. Is this true for all MBs? How and where do I find information like this. It is never clearly stated anywhere. Does the other latency timings also change?

All this does not make much sense. Basically, if you run vista 32, right now if you use top end DDR2, you are stuck with 2 GB or you will just really be throwing your money down the drain for equal or maybe even lower performance.
2GB of 1111MHz should beat 4GB of 667MHz (actually only 3.2 GB since it is a 32 bit OS), so why does anyone go with 4 GB with vista 32? Is there something I'm not understanding?
Thanks again.
I've seen your help posts and they are usually very informative and so I chose to ask you tons of questions in an effort to clear things up for me.

 

[Mondoman]

...
I, as others have suggested, would like to optimize my performance by going to 4 GB for extreme gaming.

What games are you running & why do you think 4GB will make a difference over, say, 2GB?

...
(1) I know 32 bit is limited to 3.2 GB seen at any one time.

Roughly, details depend on the MB and other hardware installed.

...what if you only used 3 x 1GB of the RAM at once.

At least 1 GB (and perhaps all) of your RAM would not be running in dual channel mode, reducing performance.

...I have read that a MB will drop the clock speed to 667MHz automatically.

Some will, some won't -- it depends on the MB design.

...I also read that with 4 DIMMs your rate command drops from 1T to 2T.

Some will, some won't -- it depends on the MB design.

...How and where do I find information like this.

Read the motherboard manuals, contact MB manufacturers.

...
2GB of 1111MHz should beat 4GB of 667MHz

It all depends on where the bottleneck is. Current non-OC'd C2D CPUs can't accept faster than a 1066MHz data rate, because that's the throughput of their FSB. Dual-channel DDR2-533 provides a 1066MHz data rate, so the extra throughput of running RAM faster than DDR2-533 is of limited benefit. Of course, latency is important, too.

You may find this post useful:
http://forumz.tomshardware.com/hardware/modules.php?name=Forums&file=viewtopic&p=1233230#1233230

 

[joejones]

thanks for the quick reply!
I'll try to answer a few questions that you proposed back to me.
I'm not sure that 4 GB would be better, but lots of people have 4 GB in their sig. I always thought more was better, but as I started doing the research, I found that is not necessarily true.
Someone had posted that if you run dual 8800GTX approximately 1.5 GB of the available RAM would be designated for video RAM. I googled this and could not find anything.
I thought 2 GB would likely be enough, but as a perfectionist, I wanted to try to get the best out of my system.
right now the 680i is one of the best MBs out there. If this one clocks down, then I can't imagine there is a MB that doesn't. I will have to do more MB research to find out exactly what my MB will do with 4 GB.
http://evga.com/products/pdf/680i manual.pdf

In your last statement, that makes sense, but when you say DDR2 533, then anything more than that is not useful? why are the top RAMs higher than 1066 then? Why is there a performance difference between them if the latencies are the same?
Thanks for all your help.

 

[joejones]

read the manual top to bottom. It didn't say anything in there about changes with 4 DIMMs.