I did a benchmark on RHEL 4 64-bit with gcc 3.4.5 and found a large difference in the performance of TSS. I have used the provided example with the following modification: --- boost_1_35_0/libs/thread/example/tss.cpp.org 2008-04-23 22:40:50.000000000 +0200 +++ boost_1_35_0/libs/thread/example/tss.cpp 2008-04-23 22:44:51.000000000 +0200 @@ -21,3 +21,3 @@ value.reset(new int(0)); // initialize the thread's storage - for (int i=0; i<10; ++i) + for (int i=0; i<100000000; ++i) { Compiled and linked with boost 1.33.1: $ time ./tss_1.33 real 0m7.734s user 0m15.379s sys 0m0.004s Compiled and linked with boost 1.35.0: $ time ./tss_1.35 real 0m21.074s user 0m41.253s sys 0m0.004s The new version of boost uses almost three times as long to complete the example. Did anyone else experience the same problem ? Regards, Arnstein Ressem