Static data and GC

[unDEFER]

Hello all!
I just have moved some big data segment to static allocated field.
So I have >64Kb static data.
And profiler shows very big increasing number (in 3 times) of 
Instruction Fetch on full_collect() method.
More accurately. The problem is in gc.Gcx.mark method, number of 
instructions of which increased in 8 times.

What happened? The GC is going crazy?
How to avoid it?