Virtual: minor updates

virtual.mdwn

@@ -62,7 +62,7 @@ References
 
 Applications:
 
-* [vbox script](https://git.fluxo.info/?p=vbox.git;a=summary).
+* [vbox and kvmx scripts](https://git.fluxo.info/vbox).
 * [plymouth - Debian Wiki](https://wiki.debian.org/plymouth).
 * [SPICE Project](http://www.spice-space.org/).
 
@@ -70,3 +70,7 @@ Other implementations:
 
 * [Marco Carnut: Ambiente "Auto-Limpante" via Virtualização Ultra-Leve Descartável - Tempest Blog](http://blog.tempest.com.br/marco-carnut/ambiente-auto-limpante-via-virtualizacao-ultra-leve-descartavel.html).
 * [Subgraph OS and Mail](https://subgraph.com/sgos/index.en.html).
+
+Tips:
+
+* If using Firefox, try to disable hardware graphics acceleration as it might impact performance and produce graphics artifacts. This behavior was seem on VMs running with qemu-kvm with SPICE.