Hmmm
Interesting, where did you see that your computer takes PC3400 ? I never knew PC3400 existed... It is certainly not a standard.... Anything over PC3200 (DDR 400) went like this PC3500 (DDR 433) PC3700 (DDR 466)
PC4000 (DDR 500) PC4200 (DDR 533) and so on... And on a DDR1 system anything over PC3200 was dependent on a FSB increase.... Meaning anything rated over PC3200 was overclocking memory.....In theory, the faster speeds your memory could support, the more you could raise your FSB..... If you slapped PC4200 (DDR 533) in your machine it would still boot up as PC3200 (DDR 400) meaning if you wanted to get it to Run at 533 mhz you would have to increase your bus speed 133 mhz...Although certain nForec4 boards let you run your memory at its rated speed without a FSB increase...
Double check where you got the information from about your memory because I beleive it is inaccurate.
If anything check your bios and it will tell you what speed of memory you are running for sure.
Or download CPUz and tell us what it says.
Put it this way, if there was such a thing as PC3400 it would be classified as DD4 416.6 lol 416.6mhz is a very odd number...
I beleive you may have PC3500 or just PC3200
And to answer your last post, no it will not damage it, it will just make your other memory run at PC2700 Speeds....