Debian Configuration :: Intel Turbo Mode Not Kicking In On Nehalem Xeon?

I've got a dual Xeon 5570 (Nehalem) server. It clocks down properly, but never, under any circumstances that I've found, clocks up past its TSC. Even when running basically nothing but cat /dev/zero > /dev/null, nothing gets clocked higher than the TSC. Below is the turbostat output, which clearly knows what the hardware is actually capable of, but it never actually achieves it. I'm running Lenny, with backported kernel 2.6.30-bpo.2-amd64. I tried the 2.6.32 backport and there wasn't any difference. know where I should look next? BIOS settings? Do I need to change some kernel option and recompile?

# ./turbostat
Nehalem multiplier 22, TSC frequency 2933 MHz
Nehalem 4 cores active: 24 mult, max turbo frequency = 3200 MHz
Nehalem 3 cores active: 24 mult, max turbo frequency = 3200 MHz
Nehalem 2 cores active: 25 mult, max turbo frequency = 3333 MHz
Nehalem 1 core active: 25 mult, max turbo frequency = 3333 MHz

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