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Hi. I'm having some really frustrating keyboard stuttering problems. At random times my guest will freeze for a moment (no more than a second) and when it unfreezes it will have entered a bunch of the same character. For example I could be trying to type "delicious cake" and instead get "deliccccccccccccccccccccious cakkke". I can keep typing while it's momentarily "frozen" and when it "unfreezes" it will register that I had hit each key I did when it was frozen.

My host is Windows 7 64-bit with a dual core Intel Core i5 (4 cores with hyperthreading) and 16 GB of RAM. I'm using VBox 4.3.28 r100309. I have this problem on both of my guests:

1. A guest with CrunchBang (Debian) Linux 64-bit. Guest Additions are installed. Configured to use 4 cores (I've actually been meaning to set it to 2 because I see it warns about using virtual cores) and 8 GB of RAM out of my host's 16 GB total. It's also configured with 2 screens and has access to all 128 MB of video memory that I can give it.
2. A guest with straight Debian 64-bit. Guest Additions are installed. I gave this one 2 cores, 4 GB of RAM, and 12 MB of video memory.

I'm on a DELL Precision laptop and I've noticed the problem whether I use a wired USB keyboard (what I'm usually using), or a wireless keyboard, or the keyboard built into the laptop. All exhibit this problem. I have noticed that the problem seems to be worse when I'm docked into my DELL dock. Other than that I'm not sure what factors might affect it. I've monitored my CPU usage from the host's perspective and I haven't noticed anything special happening when the stuttering happens. The CPU doesn't seem to spike or anything, and it seems to happen even when CPU load is at 30% or 40%.

I don't know if it's relevant, but I know my system has some slowdown problems because of low disk space and consequently longer access times -- I have 80 GB free of 500 GB. It's also probable that my VM disk files are highly fragmented, because I have them dynamically allocated.

Also, I have an almost identical setup on a desktop PC and I've never experiences any stuttering whatsoever, even when I do experience lag, which makes me feel like it's something about this specific computer, but I don't know where to even begin to figure that out.

Does anyone have any ideas what could be happening, and/or what information about my system might help shed more light on this?

Thanks so much for any help you can give!

I would try to reduce the Ram to no more than 4GB

But this will cause a lot of issues VBox deals with cores not threads so assigning 4 cores to the guest when you only have 2 is an overcommitment.

I've been meaning to take it down to 2, just kept forgetting. But this problem still happens for me on the other VM which only has 2 processors allotted to it. That being said, I've only ever run the other VM while also running the 4 processor one. Either way I'll just do it right now and see if that makes a difference. I should check when I get home to see if my desktop does not have virtual cores allotted to the guest.

Regarding the RAM, why take it down to 4 GB? Does VBox not handle more RAM than that very elegantly? Or is it a host issue? I basically use the guest as my primary OS -- I do almost everything in the guest rather than in the host. So knowing why I should take it down to 4 GB might affect my decision.

Turning it down to 2 processors seems to have fixed the issue. I forgot to check when I got home, so I don't know if my desktop already has it set lower as well. I am still curious about the RAM situation, though, if anyone has info on that.

The ram was only a suggestion. If the host runs short for any reason it will force swapping and that will slow the guest to a point you will not like.

Perryg wrote:The ram was only a suggestion. If the host runs short for any reason it will force swapping and that will slow the guest to a point you will not like.

Ah, yeah I try to be aware of that. I just do almost nothing with my host, typically, so I rarely run into swapping in the host. I do in the guest sometimes, but only the normal type of stuff. But I figure half of my RAM for my one VM seems safe. I don't normally have a second VM up. I've only been doing it recently because my Linux distro died and I need to set up a new install with a different distro and move all my configurations and stuff over.