javasaurus | Updating my cpu. Help please?

Well, I wanted to extend the life of my computer a little longer, and I enjoy doing my own upgrades. Kind of like Lego for big kids, ya know? I've done all the little stuff, like replacing video and audio cards, modems, added memory, upgraded operating systems. But this is the first time I've upgraded a CPU. For the technophiles out there, I've got a Gigabyte GA-7DX (rev 2.2) mobo, and I was running a 1GHz Athlon Thunderbird. I was able to get a 1.4GHz Thunderbird (fastest Thunderbird they made, and the max for my mobo) from ebay for next to pocketchange. Installation was much easier than expected (even spreading the silver compound and reattaching the heat sink/fan was easy). Everything is working fine. Almost. So far the processor temp runs at 53C, which is good (I understand the faster Thunderbirds could heat up a bit), and my programs work well. But my computer is identifying the chip as 1GHz, not 1.4. The code on the chip is appropriate for a 1.4, so maybe it's the BIOS? So I went to Gigabyte's site and upgraded the BIOS. Still everything works well, but still the chip is being identified as 1GHz (using dxdiag). So did I get a fake 1.4? Or is it running as a 1.0 until I upgrade some other bit of software? Or is it running as a 1.4, but claiming to be a 1.0?

Any thoughts/advice appreciated!
Thanks!