I'm having a heck of a time trying to burn DVDs with k3b. Note that I'm running a fast Athlon XP processor, I have 1 gigabyte of RAM, and a 3ware RAID1 of two fast 120GB disk drives. And my DVD drive is a new Samsung SH-W162C/BEBN. The problems are not hardware-related. Note that the hard drive array is on a PCI card, while the DVD drive is on the secondary IDE cable.
I would like to report this problem to KDE people, but they won't accept bug reports for versions as old as 3.4.3.
 Before I installed the new drive, K3b could find my old CD writer when I was logged in as a regular user. Now that I have both drives installed (the only change to the system), k3b can't find either drive (k3bsetup2 can, but not k3b). As a result, I have can only burn when logged in as root.
 This drive is capable of burning CD's at 48x, but K3b insists on only doing 16x (the DVD-R burn speed). When it finally got around to burning a DVD (see below), it set the drive to 8x. Besides this, when burning CDRs, k3b behaves correctly.
 I want to do data backups, so I copied files into a directory until it reached 4 gigabytes and then told k3d to burn that to a DVD. When adding the files to the project, k3b became unresponsive for several minutes, using 100% CPU. During this time, it did very little hard disk access. When it finished that and I told it to burn, it again became unresponsive for several minutes, using 100% CPU. During this time, it did no hard disk access. When it finally started burning, it set the burn speed to 8.2x, but only managed to achieve a burn speed of about 0.8x. During this time, it was also using 100% CPU and doing very little hard disk access.
 I decided that having lots of small files might be a problem (also, long filenames), so I balled up my data into a single 3.5GB tar file. Adding the file to a burn project was instantaneous. This time, when I told it to burn (I got smart and told it to simulate), it became unresponsive for several minutes, using 100% CPU. When it finally started burning, it again set the burn speed to 8.2x, but only managed a throughput of about 0.8x. This time, it used very little CPU time and did very little hard disk access.
 Next, I decided to create an ISO image first. That went pretty quick. Then I told k3b to burn the image (simulated this time also). When it started burning, it never became unresponsive, but it still set the burn speed to 8.2x, and only managed to achieve a throughput of 0.8x. It used very little CPU time and only tried to pull data from the hard disk at about 1 megabyte/sec (according to gkrellm).
Here's what hdparm says about the drive:
hdparm -I /dev/hdd
ATAPI CD-ROM, with removable media
Model Number: TSSTcorpCD/DVDW SH-W162Z
Firmware Revision: TS00
Likely used CD-ROM ATAPI-1
DRQ response: 50us.
Packet size: 12 bytes
LBA, IORDY(can be disabled)
DMA: mdma0 mdma1 mdma2 udma0 udma1 *udma2
Cycle time: min=120ns recommended=120ns
PIO: pio0 pio1 pio2 pio3 pio4
Cycle time: no flow control=227ns IORDY flow control=120ns
HW reset results:
CBLID- below Vih
Device num = 0
Here's my emerge --info:
Portage 2.0.54 (default-linux/x86/2005.0, gcc-3.3.6, glibc-2.3.5-r2, 2.6.12-gentoo-r10 i686)
System uname: 2.6.12-gentoo-r10 i686 AMD Athlon(tm) XP 2800+
Gentoo Base System version 1.6.14
distcc 2.18.3 i686-pc-linux-gnu (protocols 1 and 2) (default port 3632) [disabled]
dev-lang/python: 2.3.5-r2, 2.4.2
sys-devel/autoconf: 2.13, 2.59-r6
sys-devel/automake: 1.4_p6, 1.5, 1.6.3, 1.7.9-r1, 1.8.5-r3, 1.9.6-r1
CFLAGS="-O2 -march=athlon-xp -finline-functions -pipe"
CONFIG_PROTECT="/etc /usr/kde/2/share/config /usr/kde/3.2/share/config /usr/kde/3.3/env /usr/kde/3.3/share/config /usr/kde/3.3/shutdown /usr/kde/3.4/env /usr/kde/3.4/share/config /usr/kde/3.4/shutdown /usr/kde/3/share/config /usr/lib/X11/xkb /usr/lib/mozilla/defaults/pref /usr/share/config /usr/share/texmf/dvipdfm/config/ /usr/share/texmf/dvips/config/ /usr/share/texmf/tex/generic/config/ /usr/share/texmf/tex/platex/config/ /usr/share/texmf/xdvi/ /var/qmail/control"
CONFIG_PROTECT_MASK="/etc/gconf /etc/terminfo /etc/env.d"
CXXFLAGS="-O2 -march=athlon-xp -finline-functions -pipe"
FEATURES="autoconfig distlocks fixpackages sandbox sfperms strict"
GENTOO_MIRRORS="http://mirrors.tds.net/gentoo ftp://ibiblio.org/pub/Linux/distributions/gentoo/ http://gentoo.ccccom.com http://adelie.polymtl.ca/"
USE="x86 3dnow X Xaw3d aalib acl acpi aim alsa apache2 apm arts audiofile avi berkdb bitmap-fonts bonobo bzip2 cdr crypt cups curl dga directfb eds emacs emacs-w3 emboss encode esd evo exif expat f77 f90 fam fbcon ffmpeg flac foomaticdb fortran gb gcj gd gd-external gdbm ggi gif gimpprint glut gmp gnome gpm gstreamer gtk gtk2 gtkhtml idn imagemagick imlib innodb ipv6 java jpeg junit kde kerberos lcms ldap libg++ libgda libwww mad mhash mikmod mmx mng motif mozilla mp3 mpeg msn mysql ncurses nls nsplugin ogg oggvorbis opengl oss pam pcre pdflib perl php plotutils png postgres ppds python qt quicktime radeon readline samba sasl scanner sdl slang spell sse ssl svga tcltk tcpd tetex theora tiff truetype truetype-fonts type1-fonts unicode usb vorbis win32codecs winbind wxwindows xine xml xml2 xmms xslt xv xvid zlib video_cards_radeon userland_GNU kernel_linux elibc_glibc"
Unset: ASFLAGS, CTARGET, LANG, LC_ALL, LDFLAGS, LINGUAS, PORTDIR_OVERLAY
Which K3B version?