Laptop memory questions

[kcsduke]

I recently ordered a new laptop. I only ordered it with 128MB RAM because it's cheaper to purchase memory from crucial.com and install it myself than purchase the laptop with more memory. Before I do that, I have a few questions:

1. Is there any significant performance difference between 512MB (1 x 512MB) and 1024MB (2 x 512MB)? I am a farily typical user as far as the programs I run go. I usually have sypheed-claws, phoenix (with ~8 tabs), many rxvt terminals, gkrellm, fluxbox, and a few other programs running.

2. Is there any reason to have only 512MB in one slot rather than having 512MB in one slot and 128MB in the other slot? I know that it is better for a given amount of memory to have it consolidated (e.g, 1 x 512MB is better than 2 x 256MB), but is there any performance hit for splitting the memory that exceeds the benefit of having an extra 128MB of memory?

3. If I have 512MB or 1024MB, should I also add a swap partition? I ask because I recall reading a thread in which someone said that their swap frequently caused their harddrive to spin up, wasting power, and that they decided to do without swap space. Is this a good idea? If so, would it then it be definitely better to go with 1024MB over 512MB?

Thanks!

[Jimbow]

I am running a laptop with 640M (= 512M + 128M) and almost always have RAM to spare. In fact I've made /tmp and /var/tmp ram-drive partitions (tmpfs).

A couple of years ago 256M was a lot of RAM, now it is marginal (in some situations). It could be that in a couple of years you will want 1G instead of 0.5G but for now 512M or 640M should be fine.

I sometimes turn off my /var/tmp tmpfs if I am doing a mondo emerge such as kde. But that is not a good reason for buying more ram now.

I think you should almost always use a swap partition especially if you almost never use it. It is a must if you ever program. If you have a memory leak and no swap then your ram can get all used up before you have a chance to react and your system can crash. The swap space slows things down and gives you enough time to kill the leaking process.
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[wilburpan]

I have an older laptop - Dell Inspiron 5000e with a 700 MHz P3 processor. It has 512 MB of RAM set up as 2 256 MB sticks, which is the maximum this laptop can hold (I told you it was old) with a 512 MB swap partition, which is probably overkill. However, my system runs so much better than when I had 128 MB RAM and a 256 MB swap partition.

I'm perfectly happy with its performance. I typically run KDE, with XMMS, Konqueror, OpenOffice, and Kmail going at the same time, and have not noticed much slowdown even if I am emerging something at the same time.
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[Unne]

I have 512MB and I run KDE and plenty of memory-hogging programs, but my swap partition almost never gets touched. But that's ALMOST never, not absolutely never. Every once in a while a few MB will be swapped, for whatever reason. So I'd say you probably should have one. Typically I have about 300MB free RAM (not counting buffers and caches and whatnot). I probably wouldn't bother getting 1024MB.

If you have DDR RAM, from what I understand, you need to pair it up, like 2 256MB chips instead of one 512MB chip, if you want the maximum performance. In that case 2x512MB might be a good idea, I guess. I'm no expert on RAM though.

[Garbz]

the pairing of ram only affects perfomance if your chipset supports dual channel memory addressing. And i'm not sure if laptops support that yet.

Other than that there's no resaon other than price that you would choose 2x256 over 1x512. 1x512 has the advantage of future expansion.

Also just a warning on running 640mb of ram. Ram is the number 1 source for system stabilities. So buy quality ram and if at all possible use the same sized ram in each slot. Having 2 chips that differ that greatly might cause unexpected problems.

I know i go overboard, but i've had too many problems with dodgy ram. If you do have dual channel as well, ensure that the ram is the same brand, and a greatly neglected fact the same product batch as well. i have in the past had performance issues from subtle differences.
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[kcsduke]

Thanks for the help, guys. I think I'm going to get 1x512MB (so I could expand to 1GB if I ever needed to) from crucial.com and remove the 128MB coming on the laptop. And I'll definately add a swap partition. It's a 60GB drive so I'm not really crunched for space.