I've noticed that after couple of weeks run the latest optware transmission (2.41-1, but had similar issues with earlier ones) eats up too much memory (RT-N16, 1.9.2.7-rtn-r3497).
In fact it starts to impact performance after some time (e.g. NFS goes only half speed).

ps -A --sort -rss -o comm,pmem,rss,vsz | head -n 6
gives e.g. the following result:
Code:
COMMAND         %MEM   RSS    VSZ
transmission-da 53.4 67804 146708
transmission-da 53.4 67804 146708
transmission-da 53.4 67804 146708
transmission-da 53.4 67804 146708
tor              4.3  5456  14640
Checking which part of Transmission takes the memory, it's heap:
cat /proc/$(ps afx | sed -n 's/[^0-9]*\([0-9]*\).*transmission\-daemon.*/\1/p' | sed -n '1p')/smaps | awk 'N
R%8==1,NR%8==3'

Code:
00400000-00492000 r-xp 00000000 08:02 33880      /opt/bin/transmission-daemon
Size:                584 kB
Rss:                 468 kB
004a1000-004a3000 rw-p 00091000 08:02 33880      /opt/bin/transmission-daemon
Size:                  8 kB
Rss:                   8 kB
004a3000-08e5c000 rwxp 004a3000 00:00 0          [heap]
Size:             141028 kB
Rss:               66260 kB
2aaa8000-2aaae000 r-xp 00000000 08:02 294910     /opt/lib/ld-uClibc-0.9.28.so
Size:                 24 kB
Rss:                  12 kB
2aaae000-2aab0000 rw-p 2aaae000 00:00 0
Size:                  8 kB
Rss:                   0 kB
2aabe000-2aabf000 rw-p 00006000 08:02 294910     /opt/lib/ld-uClibc-0.9.28.so
Size:                  4 kB
Rss:                   0 kB
2aabf000-2aac0000 r-xp 00000000 08:02 294912     /opt/lib/libintl-0.9.28.so
Size:                  4 kB
Rss:                   4 kB
2aac0000-2aacf000 ---p 2aac0000 00:00 0
Size:                 60 kB
Rss:                   0 kB
2aacf000-2aad0000 rw-p 00000000 08:02 294912     /opt/lib/libintl-0.9.28.so
Size:                  4 kB
Rss:                   0 kB
2aad0000-2aad1000 r-xp 00000000 08:02 294915     /opt/lib/librt-0.9.28.so
Size:                  4 kB
Rss:                   0 kB
2aad1000-2aae0000 ---p 2aad1000 00:00 0
Size:                 60 kB
Rss:                   0 kB
2aae0000-2aae1000 rw-p 00000000 08:02 294915     /opt/lib/librt-0.9.28.so
Size:                  4 kB
Rss:                   0 kB
2aae1000-2ab28000 r-xp 00000000 08:02 295058     /opt/lib/libevent-2.0.so.5.1.0
Size:                284 kB
Rss:                 172 kB
2ab28000-2ab38000 ---p 2ab28000 00:00 0
Size:                 64 kB
Rss:                   0 kB
2ab38000-2ab39000 rw-p 00047000 08:02 295058     /opt/lib/libevent-2.0.so.5.1.0
Size:                  4 kB
Rss:                   4 kB
2ab39000-2ab89000 r-xp 00000000 08:02 296988     /opt/lib/libcurl.so.4.2.0
Size:                320 kB
Rss:                 220 kB
2ab89000-2ab98000 ---p 2ab89000 00:00 0
Size:                 60 kB
Rss:                   0 kB
2ab98000-2ab9a000 rw-p 0004f000 08:02 296988     /opt/lib/libcurl.so.4.2.0
Size:                  8 kB
Rss:                   8 kB
2ab9a000-2abce000 r-xp 00000000 08:02 297441     /opt/lib/libssl.so.0.9.7
Size:                208 kB
Rss:                  28 kB
2abce000-2abde000 ---p 2abce000 00:00 0
Size:                 64 kB
Rss:                   0 kB
2abde000-2abe1000 rw-p 00034000 08:02 297441     /opt/lib/libssl.so.0.9.7
Size:                 12 kB
Rss:                   0 kB
2abe1000-2ad0a000 r-xp 00000000 08:02 295056     /opt/lib/libcrypto.so.0.9.7
Size:               1188 kB
Rss:                 228 kB
2ad0a000-2ad19000 ---p 2ad0a000 00:00 0
Size:                 60 kB
Rss:                   0 kB
2ad19000-2ad2b000 rw-p 00128000 08:02 295056     /opt/lib/libcrypto.so.0.9.7
Size:                 72 kB
Rss:                  40 kB
2ad2b000-2ad2f000 rw-p 2ad2b000 00:00 0
Size:                 16 kB
Rss:                   4 kB
2ad2f000-2ad31000 r-xp 00000000 08:02 294944     /opt/lib/libdl-0.9.28.so
Size:                  8 kB
Rss:                   4 kB
2ad31000-2ad41000 ---p 2ad31000 00:00 0
Size:                 64 kB
Rss:                   0 kB
2ad41000-2ad42000 rw-p 00002000 08:02 294944     /opt/lib/libdl-0.9.28.so
Size:                  4 kB
Rss:                   0 kB
2ad42000-2ad59000 r-xp 00000000 08:02 296922     /opt/lib/libz.so.1.2.5
Size:                 92 kB
Rss:                   8 kB
2ad59000-2ad68000 ---p 2ad59000 00:00 0
Size:                 60 kB
Rss:                   0 kB
2ad68000-2ad69000 rw-p 00016000 08:02 296922     /opt/lib/libz.so.1.2.5
Size:                  4 kB
Rss:                   0 kB
2ad69000-2ad78000 r-xp 00000000 08:02 294920     /opt/lib/libm-0.9.28.so
Size:                 60 kB
Rss:                  24 kB
2ad78000-2ad87000 ---p 2ad78000 00:00 0
Size:                 60 kB
Rss:                   0 kB
2ad87000-2ad88000 rw-p 0000e000 08:02 294920     /opt/lib/libm-0.9.28.so
Size:                  4 kB
Rss:                   4 kB
2ad88000-2ad97000 r-xp 00000000 08:02 294945     /opt/lib/libgcc_s.so.1
Size:                 60 kB
Rss:                   8 kB
2ad97000-2ada6000 ---p 2ad97000 00:00 0
Size:                 60 kB
Rss:                   0 kB
2ada6000-2ada7000 rw-p 0000e000 08:02 294945     /opt/lib/libgcc_s.so.1
Size:                  4 kB
Rss:                   0 kB
2ada7000-2adb4000 r-xp 00000000 08:02 294907     /opt/lib/libpthread-0.9.28.so
Size:                 52 kB
Rss:                  32 kB
2adb4000-2adc3000 ---p 2adb4000 00:00 0
Size:                 60 kB
Rss:                   0 kB
2adc3000-2adc8000 rw-p 0000c000 08:02 294907     /opt/lib/libpthread-0.9.28.so
Size:                 20 kB
Rss:                   4 kB
2adc8000-2adca000 rw-p 2adc8000 00:00 0
Size:                  8 kB
Rss:                   0 kB
2adca000-2ae68000 r-xp 00000000 08:02 294908     /opt/lib/libuClibc-0.9.28.so
Size:                632 kB
Rss:                 260 kB
2ae68000-2ae78000 ---p 2ae68000 00:00 0
Size:                 64 kB
Rss:                   0 kB
2ae78000-2ae7a000 rw-p 0009e000 08:02 294908     /opt/lib/libuClibc-0.9.28.so
Size:                  8 kB
Rss:                   8 kB
2ae7a000-2aed7000 rw-p 2ae7a000 00:00 0
Size:                372 kB
Rss:                  12 kB
2af83000-2b039000 rw-p 2af83000 00:00 0
Size:                728 kB
Rss:                   0 kB
7f1fc000-7f200000 rwxp 7f1fc000 00:00 0
Size:                 16 kB
Rss:                   8 kB
7f3f9000-7f400000 rwxp 7f3f9000 00:00 0
Size:                 28 kB
Rss:                  20 kB
7fbe0000-7fbf5000 rwxp 7fbe0000 00:00 0          [stack]
Size:                 84 kB
Rss:                   8 kB
7fff7000-7fff8000 r-xp 7fff7000 00:00 0          [vdso]
Size:                  4 kB
Rss:                   4 kB
Anyone having similar experience?
Any solution beyond restarting Transmission here and there (which seems to fix it, so it's not traffic or file set size related).