Used right now is 899 MB, which is a bit much, but you still have more than 1 GB left.

So actually you are using 899 MB of RAM, so plenty of RAM available to your system. Maybe you could post the output with your "high performance apps" running?

Ok, you just showed me, that I don't understand the thing about it. I thought that used/free memory is in the first line.. my bad, I am sorry.
Could you please explain it to me little bit or point me to some article about it? Thanks much.

Also, for this "benchamrk", I started to render something, and put there higher anti-aliasing and reflections etc. This happened first time now - whole system freezed and start lagging then, so I switched to another run level, tried to log in (still lagging), and ran top. Before I run it (top commande), system killed chrome browser, with message "out of memory". Then everything worked as normally. Actually, I have put there little higher options comparing to those I use normally, so it should not happen again.

After the incident I ran free command, and copied:

total used free shared buffers cached
Mem: 2012 1735 277 0 1 187
-/+ buffers/cache: 1546 465
Swap: 0 0 0

Oh yes, and sorry about the time, I am new here, and I got used to forums which display new posts on the top of thread, so I took me some time to figure out that your posts are hidden on another page. Thanks for patience &*help.

Cute explanation of Linux memory usage: http://www.linuxatemyram.com/

Well, I posted a link earlier:
http://www.linuxatemyram.com/
The rest is being used for disk cache to speed up your experience, but this RAM is released as needed.

For that one you have only 465MB free. Yes, you could use some more RAM, another 1 or 2 GB should do. If you try to run lots of things at once it will run out of RAM, in which case it's good to have a swap partition or file to prevent the oom (out of memory) killer from killing programs. I suspect chrome may have had a memory leak.

Looking at your "free" output, It appears that you don't have any swap defined. Your system, as configured, should be using some swap though not much.

With no swap, when you do your video work and fill your RAM, your system will grind to a halt as it tries to work out the memory problems.

Enable a swap partition or at least a swap file, and you will find your system running a lot more smoothly.

It doesn't look to me like you need more RAM right now though.

Edit:

Just for reference, here is what my system says for "free":
Note that in spite of showing huge amounts of cached memory, I do have a bit of swap in use anyway.

d'oh, I didn't read all the new posts. Call me blind

I was telling the OP that, I posted late, not seeing your post.

Ok, thanks. Well I am glad that they've made a page right for me.
About the swap.. yeah I have swap partition defined and enabled, but it has been falling down, because of invalid UUID number. (I'll take a look on it).
So I should go for 1/2 GB of memory, right?

Anyway, jiml8: from code you provided, you seem to have about 8gb of RAM, whats the use of it? I mean, do you use your computer as server, or for some rendering or editing videos? Just curious. I have 2gb of ram in here, so compared to yours, it's nothing. Well, I probably would use new rams anyway, since I play some games sometimes, not much, but sometimes.

So to get back to the original topic. Should I go for CL7 lower freq. memory, or CL9 memory with higher clock speed? As you could see, I have two gigabytes of ram installed now, their running at speed of 1333 Mhz. I could buy 1/2GB of CL7 RAM running 1333 Mhz, and those new modules would be used fully. Or I might go for CL9 1600 MHz RAM, and then, add it to existing ram and lower clock rate, or remove the old modules (Corsair) and use only new rams with higher frequency. What do you think about it?

Thanks for quick responses, your help is appreciated.

You could do either really, but it will work better if you use the same or similar RAM modules so that dual/triple channel works properly.

I see you have 2x1GB sticks, so if you have 4 RAM slots, you would buy either 2x1GB or 2x512MB ... personally I'd get 2x1GB 1333 Mhz.

Remember to check the manual and see what the mobo supports and the arrangement of the sticks. You have to put equal amounts of RAM per channel, so that should help you decide how much.

Also remember that to work with 4GB RAM you either need PAE enabled in the kernel or a 64-bit kernel.

Well, what I didn't tell you when I posted that free command is that I have three virtual machines running currently, and they are sucking up a lot of the RAM. I am writing this post on an OpenSUSE 11.3 virtual machine that has 2 gigs of RAM dedicated to it.

So, I actually am using almost all of the 8 gigs RAM at the present time, even though the free command (executed from the Mandriva Linux host) doesn't realize that and just calls the RAM cached.

Here is the output of free, from within this VM:

H_TeXMeX_H: Ok, so I shall go for 1 or 2 (depends on cost, I'd say I need only one now, but difference between 1GB and 2GB are not big) gigabytes. I have 4 slots for RAM, but I am not sure if I would not need bigger amounts in future, so I'd like not to fill motherboard fully. I know that dual/etc. channel can make it better, especially with my AMD Phenom II processor.

jiml8: Oh, ok, thanks for explanation.

Dual channel is ESSENTIAL , so do get RAM sticks so they work with dual channel. If not, you will only get half the transfer rate, and trust me, you will notice !

Well, I meant it like I could go for triple channel or something like that, since I don't want to use all slots available from motherboard (in case i'd want more ram in future). So I looked through eshops little bit, and found: (its not supposed to be advertisement but it's kingston) 2GB DDR3 1333MHz CL7 HyperX RAM. Do you think it's good choice?

Buying same modules as I have now is not a good idea, since I was buying them before 2 years, didn't have much money left, and I use them just to make computer run.

Triple channel is only supported by Intel Core i7 9xx-CPUs.