1gb dual channel vs 1.5gb

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fartonmyear · #1 Post by **fartonmyear** » Thu Aug 31, 2006 4:28 pm

would it be better to have 1gb of dual channel memory vs 1.5gb of memory? also do you have to run the same brand? if so how would you know what memory is inside the laptop without opening it up?

pianowizard · #2 Post by **pianowizard** » Thu Aug 31, 2006 5:31 pm

I have also wondered about the same thing. Let's hope someone will provide an answer.

snife · #3 Post by **snife** » Thu Aug 31, 2006 6:19 pm

IMHO - more memory is always going to outweigh the benefits of dual channel, i think its only something that becomes a factor when you have more than 2 slots and then deciding on the configuration of your memory would be important

nelson · #4 Post by **nelson** » Thu Aug 31, 2006 7:09 pm

You also have the option of installing two 1 gigabyte modules and getting 2 gigs dual channel. As for RAM brand, in general a good software program to tell you what brand of RAM you have is CPU-Z. But it's not able to detect the RAM type on my T60.

pianowizard · #5 Post by **pianowizard** » Thu Aug 31, 2006 7:33 pm

nelson wrote:You also have the option of installing two 1 gigabyte modules and getting 2 gigs dual channel.

But for something like the X40, it has one non-removable 512MB stick, and a free slot that can accept up to 1GB. What I wanted to know was whether it's better to use 512MB or 1GB in that free slot. I have tried both and didn't notice any difference, although I wasn't sure if the 512MB in the slot exactly matched the soldered one.

mattbiernat · #6 Post by **mattbiernat** » Thu Aug 31, 2006 8:11 pm

snife wrote:IMHO - more memory is always going to outweigh the benefits of dual channel, i think its only something that becomes a factor when you have more than 2 slots and then deciding on the configuration of your memory would be important

how about 2x512mb versus 1x1gb?

Qrmunoz · #7 Post by **Qrmunoz** » Thu Aug 31, 2006 8:27 pm

pianowizard wrote:
nelson wrote:You also have the option of installing two 1 gigabyte modules and getting 2 gigs dual channel.
But for something like the X40, it has one non-removable 512MB stick, and a free slot that can accept up to 1GB. What I wanted to know was whether it's better to use 512MB or 1GB in that free slot. I have tried both and didn't notice any difference, although I wasn't sure if the 512MB in the slot exactly matched the soldered one.

It depends on if the laptop supports dual channel memory. If not then it would be better to get the 1gb.

#8 Post by **archer6** » Thu Aug 31, 2006 8:47 pm

The T60/p series is dual channel capable. To enable dual channel functionality you must have both memory slots populated with the exact same amount of ram, with the same speed. Different brands make no difference.

An example is: in the event you have 512 in the main slot, then put 512 in the open available slot you then have 1GB total with dual channel operation. Or two 1GB modules for 2GB dual channel operation.

Another example is: you have 512MB in one slot and 1GB in the other slot. Now it runs in the single channel mode and you get performance that is just a tick faster than if there was only 512MB in that second slot. So that is a waste of money and ram.

I have tried both of the examples above and the speed difference with dual channel enabled with a total of 2GB is really impressive.

Hope this helps.
Cheers....

pianowizard · #9 Post by **pianowizard** » Thu Aug 31, 2006 9:01 pm

How do I find out whether a laptop is dual-channel capable?

#10 Post by **archer6** » Thu Aug 31, 2006 9:06 pm

pianowizard wrote:How do I find out whether a laptop is dual-channel capable?

Look it up in the tabook, or call tech support.

pianowizard · #11 Post by **pianowizard** » Thu Aug 31, 2006 9:10 pm

I see, so it's not stated in the BIOS.

#12 Post by **archer6** » Thu Aug 31, 2006 9:11 pm

pianowizard wrote:How do I find out whether a laptop is dual-channel capable?
From your signature:
IBM X40: 1.2G PM/1.5GB/2.76lbs
IBM T43: 1.86G PM/512MB/5.17lbs

I did a quick lookup in the tabook: Your X40 is single channel only. Your T43 is dual channel capable.

Cheers...

pianowizard · #13 Post by **pianowizard** » Thu Aug 31, 2006 9:18 pm

archer6 wrote:I did a quick lookup in the tabook: Your X40 is single channel only. Your T43 is dual channel capable.

Thanks for your help, archer6. I think my T43 has two identical 256MB sticks, so is it automatically in dual channel mode?

BTW, I just added product numbers to my signature.

claudeo · #14 Post by **claudeo** » Thu Aug 31, 2006 9:22 pm

Dual channel 2x512MB or single channel 1.5GB? It depends on what you do. If you commit more than 1GB, as I tend to do because I run a lot of things at the same time, you're going to get a heck of a lot more performance out of the 1.5GB configuration because hitting the swap file negates the incremental performance improvement of dual channel. If you can keep your commit charge under 1GB, then go for dual channel. For the best of both, go for 2x1GB (but watch out for the bug mentioned in other threads in this forum). This being said, Windows XP seems to have some odd memory management issues with 1.5GB, maybe because it is not a power of 2 multiple of 128MB. (256, 512, 1G, 2G). For example, IE links will mysteriously stop working when you run out of physical memory.

#15 Post by **archer6** » Fri Sep 01, 2006 12:30 pm

pianowizard wrote:Thanks for your help, archer6. I think my T43 has two identical 256MB sticks, so is it automatically in dual channel mode?

Yes you are in 2 channel mode with 2 256 modules. Remember, to activate the two channel mode, one must have 2 memory modules, one in each slot, they must be identical in amount of ram and speed, different brands is ok.

So 2x256, or 2x512, or 2x1GB would provide dual channel operation and very fast speeds, each appropriate to the total amount of ram you have.

The problem occurs when you have two different amounts (same speed) in each slot. Referring back to my original example, if one is 512 and the other is 1GB, the computer operates in single channel mode and the resultant speed is just barely faster than if you were running a pair of 512mb, one in each slot. So in fact you have a 1GB stick that is only producing like a 512mb in that slot. And you are not enjoying the benefits of the dual channel mode.

Regarding the OS, Windows is perfectly well equipped to handle either scenario.

Therefore two heads (oops) memory modules are better than one....

laundromatt · #16 Post by **laundromatt** » Fri Sep 01, 2006 3:27 pm

let's say you install two modules that you think are alike - is there a way to tell if the dual channel feature is working or not?

nelson · #17 Post by **nelson** » Fri Sep 01, 2006 5:24 pm

I think the CPU-Z program will tell you if dual channel is enabled. On my new T60 with identical 1 gigabyte modules the Memory tab displays "Channels #: Dual". I don't have something without dual to compare to, sorry.

laundromatt · #18 Post by **laundromatt** » Fri Sep 01, 2006 6:47 pm

thanks nelson. i tried it, and got the same output when i tried a configuration of 1 512MB and 1 1GB, so maybe it just tests whether the hardware supports it, not whether it's actually on?

can you tell me what it says on the Frequency Field under Timings on the Memory tab? mine says 333 mhz.

jagged · #19 Post by **jagged** » Fri Sep 01, 2006 10:23 pm

I've had T60's with 1GB (512x2) and 1.5GB (1GBx1, 512x1) and 1.5GB performs noticeably better.

In fact, for most computer jobs, I would recommend 1.5GB espeically if you don't tinker with all the bloatware that came with your laptop.

nelson · #20 Post by **nelson** » Sat Sep 02, 2006 11:53 am

laundromatt wrote:can you tell me what it says on the Frequency Field under Timings on the Memory tab? mine says 333 mhz.

332.5 MHz. FSB:DRAM is 1:2, and the timings are 5/5/5/15/21

For comparison, my 2 year old Athlon 64 desktop machine is 200MHz, CPU/11, 2.5/3/3/8/11.

1gb dual channel vs 1.5gb

1gb dual channel vs 1.5gb

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