Winbond BH-5 and a simple Vdimm mod, or a booster if thats easier.
Might be more expensive to buy BH-5 (if you wait for a deal to appear, sure you find 1GB of some old skool BH-5 that will do the trick easy).
Study the Vdimm mod over and over, i'm sure you will figure it out, save buying a booster.
Reaching 243MHz 1:1 2-2-2-5 PAT will not be a problem at your speed 3.4GHz, which is fast as you can basically.
Just remember, putting in high latency ram will kill performance. Putting it this way, would be like running a 2.4GHz cpu in the RAM situation. Buffered bandwidth will be up, but its unbuffered that matters, and most importantly how fast the cpu get access the data.
Latency is like having a 10000rpm harddrive as compared to a 4200rpm (exaggerated).