can 3GB RAM be run in dual channel mode?

I know you need to have the same RAM sticks in each DIMM slot to run dual channel e.g. 2x1GB. BUT since windows 32bit can only see 3GB RAM max, if i put 2x2GB sticks in my laptop would I get the benefit of dual channel mode? Or will it be as though I have 1x1GB and 1x2GB sticks?

Thanks.

 

I tried the two combination, but I couldn't see a significant difference in performance between 3GB and 4GB so I put my second 2GB module in another notebook and I'm running on 3GB.

Sandra's memory bandwidth benchmark shows a slight difference in performance as reported in the dual channel RAM thread.

John

 

I think it uses up to 1GB of each ram as dual channel.

 

If you put in 4GB whatever it sees will run in Dual channel. If you put i 1X2GB and 1X1GB=3GB it will run in what Intel calls "Flex Memory" also called asymmetric RAM array/mode. Which as MYK said means 2GB (1GB from each DIMM) runs in dual channel the last 1GB runs in single because it has nothing to match up with (so no dual). But look at what John said. You can't tell, we are talking 3% on a benchmark, the more used instructions either start or migrate to the front (2GB) where true dual channel (or so I think I read in an Intel document). So real world not a noticable difference.

 

Yes, your system will work in dual channel mode. The OS will not see all of the RAM, but your chipset will still perform in dual channel.

 

Thanks guys. Im getting a new laptop with 1GB ram and will upgrade myself since its a lot cheaper. I was just wondering if its worth splashing out on 4 GB since soon enough it, like 2GB, will be standard.

Guess investing now means I wont have to bother upgrading again in future.

 

I went from 3GB to 4GB, and the difference is minimal at best. It didn't really cost me anything to do the upgrade though; I sold my 1GB stick for the same that it cost me for the 2GB stick.

It might be worth it to get RAM with tighter timings though. Since I already had a 2GB SODIMM, it didn't make any sense to either buy a single faster SODIMM, or to replace everything. In your case though, if you're just going to get 1GB of RAM in it and replace it, something like this may be worth your while:

http://www.newegg.com/Product/Product.aspx?Item=N82E16820231154

(the one I got was ordinary 5-5-5-15. The one I linked above is 4-4-4-12. The jury's still out as to whether it'll make a noticeable difference though)

 

Is that Newegg RAM 4-4-4-14 at 667MHz or at 533MHz? If it has those timings at the higher frequency then it should be rated higher than PC5300. You can use CPU-Z to check.

John

 

Unless you are a power-user, more than 2gb is not needed.

 

Please explain John as I am missing something?

Edit: Oh and help me with back up while you are at it!

 

Click the link. It tells you right in the description:

G.SKILL 4GB (2 x 2GB) 200-Pin DDR2 SO-DIMM DDR2 667 (PC2 5300) Dual Channel Kit Laptop Memory - Retail

 

Correct. Most people don't need over 2GB of RAM. I upgraded to 4GB of RAM for a few reasons. I have 3318MB free, and since my system has an X3100 video chip, it can eat up 384MB of that RAM. After that, I have a little bit shy of 3GB of RAM for the applications I run simultaniously, along with the OS overhead. I also wanted to see how much more speed I could wring out of this thing by running in a 2GB x 2GB configuration. I know that quite a few of the people who visit this forum are gamers and this laptop wouldn't cut the mustard for them video wise. For me though, it's the best $749 (+$247 for the new CPU) I ever spent on a system.

CPU wise, this sucker matches, if not beats my water cooled Athlon64 X2 4800+ desktop.

On this laptop I routinely run Adobe Photoshop Lightroom 1.3.1, and ITP2.0 ( www.pixagent.com) at the same time, as well as RAWShooter Premium (for full-screen previews of RAW files as I shoot them), and Paint Shop Pro 10 (for watermarking). As camera RAW files are being streamed to the laptop (and ITP is handling the transfer), RAWshooter is doing a quick import of the files and displaying a real-time preview. At the moment I launch Lightroom separately, but I plan on having it run concurrently so that it auto-imports the files too and applies a color preset to the images. At the end of everything, PSP10 batch watermarks the files (since Photoshop stinks in this regard).

 

1. I have my doubts that that G-Gkill RAM has timings of 4-4-4-14 at 667MHz. PC5300 usually has 5-5-5-15 at 667MHz. I recall that several months back we discussed some 667MHz RAM with those timings and concluded that the advertised timings were for 533MHz.

2. What backup?

John

 

I do remember that discussion and have never seen "proof" so skeptical but what I did not understand was when you said, if it does have those timings it should be called something other than PC5300. It threw me because the timings don't determine the PC#### they just fall into normal amounts like you said PC4200 is usually 4. And the 2nd thing, I started a thread because I need help with "back up" here is a link.

 

OK. Maybe I am wrong in thinking that CL=4 @ 667MHz should have a higher rating than CL=5 @ 667MHz, but I'm certain that it would have a significantly better bandwidth.

John

 

Agreed John (on bandwidth), maybe as much as 20% in real world. Because latency is not calculated into the PC#### in any way but it is important. As you and I have commented on in threads. The the PC53000 vs PC4200 is not substantial. And I think both of us know why, when you increase the speed by 20% but at the same time increase the latency by 20% the results end up being very close. Anyway I just wanted to know if you knew something I didn't. I just read a thread where they think PC6400 will have a lower CL if running at 667Mhz. I have never read that and they just think it will work like PC5300 which does do that. I only tell you because this will likely be the next hot RAM topic because if true, yea, great. But I don't have the money to go out and test myself. And I doubt. Cheers!