Laptop RAM

bonzodog2

I read somewhere that laptops work better with both SODIMM RAM slots with an identical card, rather than 1 slot filled with a card of twice the capacity.
Does anybody have any evidence for or against this ?

Alanstrainor

It's not the capacity you need to keep the same it's the speed of the memory. You'll see some DDR2 so-dimm cards will be called something like "DDR2 SO-DiMM PC4200 1GB", it's the bit in bold that you should match to get the best out of your RAM. The example given would be on the slower side of things

Voodu Child

bonzodog2 wrote: »

I read somewhere that laptops work better with both SODIMM RAM slots with an identical card, rather than 1 slot filled with a card of twice the capacity.
Does anybody have any evidence for or against this ?

You're talking about achieving a dual channel configuration. More specifically, a synchronus dual channel configuration. Which would require two modules of identical size and speed.

However, with two differently sized modules, you'll get asynchronus dual channel once your chipset supports it. Its slower than synchronus dual channel, but faster than pure single channel.

Memory speed isn't a major issue for most laptop users, so I wouldn't worry about it tbh. But if you are buying fresh ram, you might as well go for (for example) 2x2GB rather than 1X1GB + 1X2GB, simply because its so cheap these days.

ressem

It depends on the laptop's chipset.

http://en.wikipedia.org/wiki/Dual-channel_architecture
is the technology, but even if your laptop motherboard supports it, you may not see much of a difference.

bonzodog2

OK, thanks. Its quite old, 1GHz Dell C610, 512MB on 1 card; its fast enough. I bought another for a friend, with 256MB on 1 card, but its a tad slow and I thought I'd add another 256 card. Obviously the speed should be the same, the ones I have are PC133 CL3 spec

Voodu Child

bonzodog2 wrote: »

OK, thanks. Its quite old, 1GHz Dell C610, 512MB on 1 card; its fast enough. I bought another for a friend, with 256MB on 1 card, but its a tad slow and I thought I'd add another 256 card. Obviously the speed should be the same, the ones I have are PC133 CL3 spec

In this situation (having such a small amount of ram to begin with), 'more' is MUCH more important than trying to achieve some on-paper advantage.. So I would buy the biggest stick that is technically possible. What OS are you running?

bonzodog2

XP SP2. The one with 1 512MB card is adequately fast, but the 256MB machine is lacking somewhat. Its for a friend with low budgets ....

Black Swan

There are other factors affecting laptop speed or capacity too besides RAM? For example, FSB, or what your OS will handle, or graphics or video card capacity for gaming? And to overclock a laptop would pose heat probs. So just adding more RAM may end up with diminishing returns and a waste of money for a laptop at some point?

bonzodog2

Maybe so, but I won't be changing the FSB speed or trying to overclock it

the_syco

bonzodog2 wrote: »

Dell C610, 512MB on 1 card

Max for the C160 is 1GB. Some places offer 512MB for €76, but having looked around myself, I've found some ebay sites on the web offering 1GB (2*512MB DIMMS) for just over €32. Found the sites by getting power-seller names on boards. One was "black tiger" shops, or something. Will post up later when at home.

Voodu Child

bonzodog2 wrote: »

XP SP2. The one with 1 512MB card is adequately fast, but the 256MB machine is lacking somewhat. Its for a friend with low budgets ....

Yeah for XP 256MB is less than ideal. Especially nowadays, as all the apps that people use (browers, music management etc) have gotten more and more bloated over the years). And most people have tonnes of crapware and updaters running in the background.

Basically it means the OS will be constantly running out of ram and using the HDD as virtual memory. Which you don't want, thats why you're finding it 'slow'. I would consider 512MB (256+256) a minimum for XP nowadays, but if you can put in a 512MB stick (ie 256+512) for not too much more €, go for it. Thats what I meant earlier when I said don't get too worried about going for symmetric dual channel.

And as the_syco says, pay attention of course to what is compatible and what the system can take. Is that max 1GB for the system, or max 1GB per slot?

Overheal

Blue_Lagoon wrote: »

There are other factors affecting laptop speed or capacity too besides RAM? For example, FSB, or what your OS will handle, or graphics or video card capacity for gaming? And to overclock a laptop would pose heat probs. So just adding more RAM may end up with diminishing returns and a waste of money for a laptop at some point?

I wouldnt overclock a laptop unless you wanted to mount it to an elaborate cooling system - and there are mods out there; most of them DIY. Liquid Cooled laptops et all.

Ram Speed, and the FSB will be the two biggest things. Theres no point in buying 1000mhz ram if the fsb is 600mhz.

Slots also. Each stick of ram is a Page. If you have 4 available slots you want them all filled. You want 4x256 more than you want 2x512. It just makes I/O that much faster.

Some specs say they cant handle more than 2gb of ram but i told it to feck off, put 4gb in anyway, and its going fine. Im still trying to figure out why this is supposed to be a bad idea. Not all specs that say they are limited to X GB actually are.