1.0-9755 (and earlier) don't like kexec
When "rebooting" the kernel via kexec, the nvidia driver fails to initialize with kernel 2.6.20+, iirc.
NVRM: RmInitAdapter failed! (0x32:0xffffffff:1526)
NVRM: rm_init_adapter(0) failed
I can't say whether it worked with earlier kernels as then sata_nv had problems with kexec and I couldn't boot.