The Athlon Thunderbird is compatible with two chipsets, VIA's KT133 chipset and AMD's 751 chipset. Since the Thunderbird 1.1GHz is a performance CPU, we find it highly unlikely that you will see one matched to an AMD 751 chipset. Instead, almost every Athlon Thunderbird will be mated with a motherboard armed with VIA's KT133 chipset.
On the whole, we are positive about the KT133 chipset, though we are not professing our love for it. On the one hand, it is by far the most stable chipset we have seen from VIA. We were pleasantly surprised by its stability and compatibility across a wide range of motherboards. On the other hand, we have run into small problems here and there. With the test system AMD sent us, when using a single memory stick, the stick had to be mounted in the middle memory slot or else the machine would not boot. This touchiness with memory was a known early problem of the KT133 chipset and it looks like VIA may not have the problem completely licked. This is a relatively minor compatibility problem, though it may be a symptom of something larger. In the end, we like VIA's KT133 chipset though we think there is still room for improvement.
And so the question is, "Is there anything new with the Athlon Thunderbird 1.1GHz?" Well, other than an extra 100MHz, no. Nothing. Nada. Not an electronic sausage. We looked far and wide and the closest we came to finding something new was a .02 volt difference in the Vcore voltage setting versus what our 1GHz Athlon Thunderbird used, which is a completely insignificant difference from a number that probably changes with the tides but we decided to bring it up anyway. So with an Athlon Thunderbird 1.1GHz, you have exactly .1GHz more, 1/10th of one GHz more, 10% more GHz, or .001 THz more (however you want to look at it), than with an Athlon Thunderbird 1GHz, and nothing more. Zilch. Zippo. Zero. NOTHING!