Just downloaded speccy to try it out. When it reports my CPU is shows the following:
CPU
Intel Mobile Core 2 Duo T8300
Cores 2
Threads 2
Name Intel Mobile Core 2 Duo T8300
Code Name Penryn
Package Socket P (478)
Technology 45nm
Specification Intel® Core2 Duo CPU T8300 @ 2.40GHz
Family 6
Extended Family 6
Model 7
Extended Model 17
Stepping 6
Revision M0
Instructions MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, EM64T
Bus Speed 200.0 MHz
Rated Bus Speed 799.9 MHz
Stock Core Speed 2400 MHz
Stock Bus Speed 200 MHz
Average Temperature 36 ?C
Caches
L1 Data Cache Size 2 x 32 KBytes
L1 Instructions Cache Size 2 x 32 KBytes
L2 Unified Cache Size 3072 KBytes
Core 0
Core Speed 2600.1 MHz
Multiplier x 13.0
Bus Speed 200.0 MHz
Rated Bus Speed 799.9 MHz
Temperature 35 ?C
Thread 1
APIC ID 0
Core 1
Core Speed 2500.1 MHz
Multiplier x 12.5
Bus Speed 200.0 MHz
Rated Bus Speed 799.9 MHz
Temperature 37 ?C
Thread 1
APIC ID 1
You will notice that Core 0 is being shown as running at 2600Mhz with a multiplier of 13x and Core 1 is being shown at 2500Mhz with a multiplier of 12.5x . At stock speeds the Intel Core 2 Dup T8300 runs at 2400Mhz. It does have the ability to boost the frequency of one core to 2500Mhz but only one core and in no way will it run at 2600Mhz. Not sure why the program is reporting this as other programs like CPU-Z do not. As such this ends my bug report.