SDRAM Command Rate, 1T or 2T??

My motherboard has 2 settings, 1 for CAS latency(2 or 2.5) and 1 for command rate(1T or 2T), along with bus setting(133mhz,100mhz)which is at 133mhz. The MB uses the VIA KT266 chipset with the latest 4.34 4in1 drivers. My CAS runs fine at 2, but what is the command rate for?? What should I set it at?? Im using 512mb of PC2100 Micron RAM with an Athlon 1.4 chip,and a Geforce3 video card.

Thanx for any advise!
R&B

Personally I played with all my settings and found that cas 2, 4 bank interleaving, 2T command gave me the best benchmarks. I would recommend changing one thing, benchmarking(using SiSoft mem-benchmark), and finding your personal optimal settings. Here was my data, took me half an hour or so:

RAM= cas 2, 4 bank interleaving, 1T command rate 485, 554
cas 2.5, 4 bank interleaving, 1T command 490, 562
cas 2.5, 2 bank interleaving, 1T command 472, 558
cas 2.5, 4 bank interleaving, 2T command 491, 625
cas 2, 4 bank interleaving, 2T command 503, 627