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Memory: Full advantage of duel channel

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December 23, 2007 1:15:44 PM

I did read the "MEMORY FAQ (please read before posting)" topic on this site. This is more of a "memory/mother board" question than it is a "laptop" question. I still have a few questions about a laptop that I just purchased.

The Sony Vaio that I purchased has one 1GB stick of RAM (SODIMM PC2-5300) installed. I would like to upgrade to 2GB or 3GB of RAM. I understand that to take advantage of "duel channel" , I would need to purchase or have identical pairs. I am not sure if I can purchase another identical stick to match the first one. I have no idea where it came from. Sony suggested www.crucial.com but I still don't know how to match what is installed exactly.


My question is this....should I (to give best performance)?: (only have 2 slots)

1. Purchase an additional 1GB online of PC2-5300 giving me 2GB total but not identical and would not take full advantage of "duel channels"?

2. Purchase one 2GB stick giving me 3GB total (a 1GB and a 2GB stick)? Would the 3GB mis-match be faster than 2GB identical DIMMS? (Good question)

3. Purchase a brand new kit of 2x 1GB totaling 2GB of identical sticks. Taking advantage of duel channel BUT wasting the factory installed 1GB stick?

What would be faster 3GB (1GB and 2GB) or 2x1GB identical sticks?????


Thanks!!!!!!
a b } Memory
December 23, 2007 1:51:25 PM

You would not notice real life performance between Dual Channel and non dual channel. You would notice a performance increase between 1GB and 3GB depending on what you do.
December 23, 2007 2:01:36 PM

Some gaming and 3D applications, not much though. Some graphics and video editing. Mostly internet and word processing.

I mean, I know it sounds like a dumb question but I got confused with the term "duel channel" and "identical pairs" for best performance.

Are you saying that 2GB of identical PC2-5300's would be slower than 3GB (a 1GB stick and a 2GB stick)?
What about 2GB total of 2-1GB sticks that are not exact identical chips (both 5300 but not the same manufacture)? Is that a bad thing?
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December 24, 2007 3:00:39 AM

Anyone?????
December 24, 2007 3:30:29 AM

You dont need identical sticks to run in dual channel mode.
December 24, 2007 3:41:05 AM

skittle said:
You dont need identical sticks to run in dual channel mode.



Really????




To benefit from the performance advantages offered by dual-channel systems, you should install memory in identical pairs. Installing a kitted pair is the best way to ensure that your modules are identical, right down to the chip count.

December 24, 2007 4:09:32 AM

Identical capacity, frequency, and timings ought to be enough.
December 24, 2007 6:37:12 AM

Yeah. even two sticks that are different speeds will run in dual channel. the faster will run slower to match the other stick. i've done it so i know it works. download cpu-z and it should tell you what the current stick is. if it doesn't then buy the best matching stick of kingston, crucial or corsiar. they always seem to play best with most motherboards. good luck.
December 24, 2007 1:45:19 PM

Crucial says that If I run 2GB total it will give me a 10% increase while 3 GB total will give me a 17% increase.

I don't understand tht one???? 1 GB more but only 7% increase?
a c 128 } Memory
December 24, 2007 3:08:30 PM

The bottom line: 2 gigs is enough for most folks since they use 32 bit windows versions, which won't recognize 4 gb of memory. You can try 3 gigs, but you should run in same size pairs to keep it in dual channel; for example, I can use 2 256 meg with 2 1gb sticks and but not 256 and 1 gb in the dual channel slots. Don't mix different speed or size sticks in the pairs of dual channel slots if you can avoid it.
a b } Memory
December 24, 2007 3:51:39 PM

Triple xXx said:
Crucial says that If I run 2GB total it will give me a 10% increase while 3 GB total will give me a 17% increase.

I don't understand tht one???? 1 GB more but only 7% increase?


The reason memory speeds up your computer is, when you have enough memory your computer stops (for the most part ) using your hard drive for memory (swap files). If you have enough memory to hold all the programs that you are running at a given time, adding more memory will do nothing.
December 24, 2007 9:36:27 PM

The 7% for 1Gb more is all about diminishing returns, in this case, diminishing performance, as it nearly always is. If you could go from 1GB to 2GB and have a 10% increase, then from 2GB to 3GB for another 10%, etc, we'd fill our boards with as much RAM as possible, knowing that the returns are linear (32- and 64-bit address issues aside). You could have a 70% "increase" going from 1GB to 8GB just due to memory modules alone, though I'm not sure what the increase would be in.

Every system will have a minimum amount of memory required to boot and not hang or freeze, but you can bet the drive is grinding to dust by constantly writing to the swap file (as millwright has pointed out). Adding more memory will reduce this until you reach a point where the swap file is hardly used. Beyond this you will receive no performance benefit by having more memory.

The best way to optimize performance is always to match the modules as much as possible, in both channels. Timings for the frequency you want to run are the most important, then capacity, then brand the least important. The less the pair(s) match, the more they operate at the most conservative specifications, ie the lowest common denomintor rules.

My answers to your questions:
1. So long as the timings are the same as the module you've got, there'll be no difference in preformance compared to buying an indentical brand (you're not running SLI certified memory, or anything). If the timings are slower, then both will operate at this new, slower speed, but either way, they'll still be dual channel.

2. Wouldn't bother with the 2GB stick unless you really, really need the capacity.

3. Waste of money for the "performance" you'll get. You should be able to identify the timings using cpu-z (as mentioned by shoota) and buy another 1GB stick with the same.

2GB + 1GB will give you the same performance as 1GB +1Gb, assuming timings are identical and your apps don't need more than 2GB in total. Start your taskmgr and check the physical memory and paging file size when you've got everything running. Add the two together to get a rough idea of what you'll need in RAM. If it's close to a 1Gb or 2GB, you should go up to the next full GB (ie 2GB and 3GB respectively).
December 25, 2007 3:48:03 AM

seabreeze said:

....but you can bet the drive is grinding to dust by constantly writing to the swap file.... :lol: 

The best way to optimize performance is always to match the modules as much as possible, in both channels. Timings for the frequency you want to run are the most important, then capacity, then brand the least important.

My answers to your questions:
1. So long as the timings are the same as the module you've got, there'll be no difference in preformance compared to buying an indentical brand (you're not running SLI certified memory, or anything). If the timings are slower, then both will operate at this new, slower speed, but either way, they'll still be dual channel.

2. Wouldn't bother with the 2GB stick unless you really, really need the capacity.

3. Waste of money for the "performance" you'll get. You should be able to identify the timings using cpu-z (as mentioned by shoota) and buy another 1GB stick with the same.

2GB + 1GB will give you the same performance as 1GB +1Gb, assuming timings are identical and your apps don't need more than 2GB in total.


Thank you gentlemen very much! This really helped! I wish that I read this earlier! :cry: 

I ordered the 2GB stick from Crucial.com before I read this.

If you guys think I should send it back for the 1GB I will. I have 1GB of 5300. I ordered another 2GB of 5300. The guy from Crucial claimed that the 2GB would give me a 17% increase and the 1GB a 10% increase.

Who knows..... this stuff is confusing as heck and the fact that manufactures of these PCs don't always give you the detailed specs about what you are buying.

It looks like my total memory requirement including the page file is about 1.15GB (if I read it correctly). So based on what you mentioned, 2GB should be plenty. I have 3GB now even though there is no real added benifit and I wasted a little money.

That was exactly what I asking. 2x1GB (5300 duel channel) vs. 1GB+2GB (both 5300) Which is faster?
December 25, 2007 1:25:14 PM

I really messed up now and it's you guy's fault for not getting back to the board sooner! :D 

A 1GB stick of 5300 is $28. A 2GB stick is $75. I ordered the 2GB.

Was it worth it??????????? Maybe Crucial.com has an exact match to what I already have??????????????
December 25, 2007 2:07:31 PM

Triple xXx,
You must be careful on these forums because some people will offer advice without reading the entire thread. Example; kpo6969 had no ideal you were asking about laptop memory. For the most part we are here to help, but the final decision is yours.

You never said what OS you had on the laptop. Remember Vista needs at least 2GB so having three is just that much better should you run Vista.
December 25, 2007 5:05:12 PM

dallasjoh said:
Triple xXx,
You must be careful on these forums because some people will offer advice without reading the entire thread. Example; kpo6969 had no ideal you were asking about laptop memory. For the most part we are here to help, but the final decision is yours.

You never said what OS you had on the laptop. Remember Vista needs at least 2GB so having three is just that much better should you run Vista.



Sorry! Yes I am running Vista right now on 1GB which is not really that slow right now for me. (maybe it is andd I don't realize it.

Core 2 Duo T7100 @ 1.80GHz

Again, I guess my question is which would be better???? 2 exact-1GB sticks=2GB (5300 duel channel) OR 1GB+2GB (both 5300)????? OR am I making too big of a deal out of this????????????

I ordered the 2GB chip (1GB+2GB=3GB) but did I lose the duel channels because they are not exact pairs?

A 1GB stick was $30 and the 2GB was $75 but even if I had ordered the 1GB it may not have been an exact match to what I have and still may not be able to use duel channels because of it. No?
December 25, 2007 7:04:22 PM

Triple xXx said:
Well, it's a laptop so I will need 5300 200 pin SODIMMS.........not 240 pin. :D 

Great price though!

Sorry about that, I only saw PC2 5300
things happen when you get old
a b } Memory
December 25, 2007 7:39:28 PM

The memory has to have the same layout to run dual-channel mode: It has to have the same organization, but sometimes you can get away with different manufacturers and timings. This really depends on BIOS: Any pair that has the same layout should work at the speed and timings of the slower pair in Dual Channel mode, but BIOS might not "think so". Being that it's a Sony, I wouldn't count on much interpretation from BIOS. You could pull the memory that's in there and check to find that model: It doesn't help if a seller says "Sony model XXX memory" because there could be a dozen different models that work and depending on BIOS only one or two that will do dual-channel.

Anyway, your chipset has to support dual-channel as well. Dual-channel will have some benefit on laptops.
December 25, 2007 8:04:07 PM

Crashman said:
The memory has to have the same layout to run dual-channel mode: It has to have the same organization, but sometimes you can get away with different manufacturers and timings. This really depends on BIOS: Any pair that has the same layout should work at the speed and timings of the slower pair in Dual Channel mode, but BIOS might not "think so". Being that it's a Sony, I wouldn't count on much interpretation from BIOS. You could pull the memory that's in there and check to find that model: It doesn't help if a seller says "Sony model XXX memory" because there could be a dozen different models that work and depending on BIOS only one or two that will do dual-channel.

Anyway, your chipset has to support dual-channel as well. Dual-channel will have some benefit on laptops.



So....buy one 1GB stick to =2GB OR buy a 2GB stick to =3GB? Which is faster?

That's my question?

Will 2GB of identicle pairs out perform 3GB (1GB + 2GB) everything is 5300????????????????????
a b } Memory
December 25, 2007 8:06:44 PM

2x 1GB in dual-channel mode is USUALLY faster than 3GB, but that assumes that you rarely use more than 2GB of RAM. This is a safe assumption for most applications...as for Windows Vista it's probably a toss-up. I took Vista OFF my new notebook and put XP on it, even though tracking down the drivers took several hours.
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