This thread is a continuation of: https://ubuntuforums.org/showthread.php?t=2382751
At the risk of diverting the discussion from the OPs original topic, for my part, I will say this:
I will be the first to admit that my knowledge is that of the educated layman and not that of a virtualization, hardware or kernel expert. However, in my case, the experience is personal.
On occasion, I run a number of old games in Windows XP and Vista. Specifically, Homeworld and Homeworld 2. Even back in the XP days, these were known to tax the bare metal HW of the time quite heavily. I did not have much hope that they would run well in a virtualized environment and, sure enough, they were unplayable in VBox. Now, I have been using VBox for years and like to think that I know my way around it well enough. Yet, no matter how I tweaked it, HW2 in particular, was unplayable. A few months ago, I decided to slowly make the change to KVM. With no better hope that it would work, I tried the game in KVM. Not only did it run, it was quite playable. A far cry from my experience using VBox.
Other apps and OSes behave likewise. With practically identical settings in both, Kubuntu runs slower in VBox than KVM. It boots up slower, has more mouse jutter, and is noticeably more sluggish. Firing up an app like LibreCAD on top of Kubuntu makes this even more noticeable. LibreCAD slows the system down even more in VBox. The experience in KVM is much snappier.
Nor is this restricted to just one machine. My old laptops (Core2 Duo 2GB RAM) struggle to host a Windows Vista session in VBox. They do not struggle in KVM. I could go on.
It is not my intent to be argumentative. I like VBox, especially its ease of use. But these are real experiences. Anecdotal perhaps, but we hear the same story on these forums with enough regularity that I have high confidence that I am not some outlier.
At the risk of diverting the discussion from the OPs original topic, for my part, I will say this:
I will be the first to admit that my knowledge is that of the educated layman and not that of a virtualization, hardware or kernel expert. However, in my case, the experience is personal.
On occasion, I run a number of old games in Windows XP and Vista. Specifically, Homeworld and Homeworld 2. Even back in the XP days, these were known to tax the bare metal HW of the time quite heavily. I did not have much hope that they would run well in a virtualized environment and, sure enough, they were unplayable in VBox. Now, I have been using VBox for years and like to think that I know my way around it well enough. Yet, no matter how I tweaked it, HW2 in particular, was unplayable. A few months ago, I decided to slowly make the change to KVM. With no better hope that it would work, I tried the game in KVM. Not only did it run, it was quite playable. A far cry from my experience using VBox.
Other apps and OSes behave likewise. With practically identical settings in both, Kubuntu runs slower in VBox than KVM. It boots up slower, has more mouse jutter, and is noticeably more sluggish. Firing up an app like LibreCAD on top of Kubuntu makes this even more noticeable. LibreCAD slows the system down even more in VBox. The experience in KVM is much snappier.
Nor is this restricted to just one machine. My old laptops (Core2 Duo 2GB RAM) struggle to host a Windows Vista session in VBox. They do not struggle in KVM. I could go on.
It is not my intent to be argumentative. I like VBox, especially its ease of use. But these are real experiences. Anecdotal perhaps, but we hear the same story on these forums with enough regularity that I have high confidence that I am not some outlier.