$ free -m
total used free shared buffers cached
Mem: 744 679 64 0 33 289
-/+ buffers/cache: 356 387
Swap: 3813 0 3813
According to this you now have up to 387 MB physical (non-swapped) RAM available for the game. And you said it was 450 MB (how did you measure this?) before you changed the memory allocation of the GPU.
Well I switched to 256MB
Are you saying you switched the graphics card to use 256MB - in your BIOS?
If so, what was it set to before you did? 256 MB - (450 MB - 387 MB) = 193 MB. That's pretty close to 3 x 8² MB = 192 MB. So did you have 192 MB RAM dedicated to the GPU in BIOS before?
I tried with tiny window still crashes, see height + width below:
Don't know if the is any other settings to switch off?
Huh that's really a small dimension there. Please try at least 640 x 480, since if you go even lower this could cause other issues (and this is really not tested).
Does it still crash with the same error message, though, or is it a different one now?
I guess I need a graphics card or more ram or processor or something...?
Your GPU's OpenGL capabilities are fine. Just like titi I think what you are really missing most of all is more RAM. Unfortunately, I'm afraid that as soon as you would have enough RAM, you would probably realise that you need more processing power (CPU), too. Those are your bottlenecks, the GPU isn't.
Hardware upgrade options:
* RAM: This board can take up to 8 GB RAM (DDR2 1066*/800/667/533 non-ECC, un-buffered memory), it as 2 memory slots (so 2 x 4 GB is the maximum configuration). You will probably have 2 x 512 MB now. For dual channel memory operation you need to have two identical (same brand, speed, size and chip-type) memory modules installed. So if intend to upgrade your RAM you will most likely need/want to replace the current DIMMs by new ones. See your mainboards'
user manual for more info. An upgrade to 8 GB RAM would currently cost ~ USD 120.
*
CPU: Be sure to also read the hint about automatic
system bus downgrade with AM2+/AM3 CPUs. An Athlon 64 X2 5400+ (AM2 socket), 2x 2.80GHz, tray, model ADO5400IAA5DO, which is a Brisbane (65 nm) variant would cost about USD 70 (if you can find a shop which still has some).
* For a newer CPU, while not decreasing FSB speed, you'd also want a mainboard replacement.
Note that if you upgrade your hardware you will most likely also want/need to upgrade your BIOS to the latest revision available.