I'd like to point out that the Swap partition shouldn't be a static 8Gb, you should be setting it to roughly the same as your physical memory or double, it works much like the Windows pagefile. Also if you're testing games built for a Linux distribution (Ubuntu in this case) and are running a system other than the target system (Mac Windows or another Linux Distro) I highly recommend installing Lubuntu in VM ware as opposed to Ubuntu which is clogged up by unneeded features and the interface severely hampers performance. Most gamers will use Ubuntu 12.04/12.10 with LXDE interface, or plain Lubuntu which is minimal Ubuntu with the LXDE interface standard. I notice huge leaps in framerate differences between the two distributions and won't be going back to Ubuntu any time soon.
Back on topic with the Swap partition, I have 8Gb of physical memory, I'm likely never to use it all so system paging is useless (and thus its disabled on my Windows 8) so I made the decision to run an 8Gb Swap partition to mirror it, again likely overkill because I've gotten away with 2Gb easily before and my memory usage has never gone above 1.5Gb, even when I have a bad case of the lazy (leaving up to a hundred windows open and processes running)
Why am I prattling on like this over a virtualised system? Because users tend to go "Oh I like this," then install the system on their physical machine using the same settings and end up stuck between a rock and a hard place when its all said and done, I recently realised my mistake of using a Data partition as the home directory for my Lubuntu system when the partition was corrupted during a reinstall of Windows (I forgot that DISKPART is zero based when Windows disk manager is one based) and quick formatted the whole data drive to NTFS from EXT3, luckily I managed to recover my data and set it all back up again. But lesson learned.