Bunch of performance benchmarks show memory usage increase starting from build 8.0-graphics-scrum-h342.
In particular Guimark2.BitmapBenchmark shows 28% of memory increase.

Here are the results of MAX_MEMORY_USAGE metric for build #340 and #342 for Guimark2.BitmapBenchmark:
build #340:
 iter_01: 76788.000000 Kb
 iter_02: 76788.000000 Kb
 iter_03: 76788.000000 Kb

build #342:
 iter_01: 76776.000000 Kb
 iter_02: 106576.000000 Kb
 iter_03: 111760.000000 Kb

I did try to rollback changes integrated in #342 and found out the the following change is
the cause of observer memory increase:
 RT-9664 Simplify Animation Code - AbstractMasterTimer

The regression is easy to reproduce by running for example Guimark2.BitmapBenchmark:
> cd JFX_WS/tests/performance/GUIMark2
> ant
> java client -Djava.library.path=../FXBenchmark/lib/win32/
       -cp "JFX_HOME/rt/lib/jfxrt.jar;./dist/GUIMark2.jar;../FXBenchmark/dist/FXBenchmark.jar;../../../import/benchmarks-2.1.1/benchmarks-2.1.1.jar"
       guimark2.bm.BitmapBenchmark -i 3 -monsters 18000 -counters JFX_FPS MAX_MEMORY_USAGE