added a bit about the change to the thread ticker
diff --git a/Misc/NEWS b/Misc/NEWS
index 37ed63a..ba9204b 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -95,6 +95,15 @@
show signed values (e.g. hex(-1) currently returns "0xffffffff";
in Python 2.4 it will return "-0x1").
+ - The bits manipulated under the cover by sys.setcheckinterval() have
+ been changed. Both the check interval and the ticker used to be
+ per-thread values. They are now just a pair of global variables. In
+ addition, the default check interval was boosted from 10 to 100
+ bytecode instructions. This may have some effect on systems relied on
+ the old default value. In particular, in multi-threaded applications
+ which try to be highly responsive, response time will increase by some
+ (perhaps imperceptible) amount.
+
- When multiplying very large integers, a version of the so-called
Karatsuba algorithm is now used. This is most effective if the
inputs have roughly the same size. If they both have about N digits,