Have you tried setting it at 1T in the BIOS? That's the only way to know. Let's put it this way, you're not gonna blow up your PC by trying.
As for the RAM being able to do it: It doesn't really matter. Whether it's able to run in 1T or not has nothing to do with the RAM, and more to do with your motherboard, and the Athlon64 Memory controller.
AMD64 X2 4400+
DFI Lanparty Ultra-D
2GB Kingston Hyper-X (2-3-2-6)
TT Big Typhoon
eVGA 7900GT KO Superclocked (650/1650)
250GB Maxtor DiamondMax SATA2 HDD
Hiper Type-R 580W SLi PSU
19" Sony Trinitron CRT