I have an Intel I7.620M with 500GB HDD and 6GB RAM running on Windows 7.
I have about 2.9million hands and I am using the v3.13.8. Also my database is fresh that means i have created it a week ago and all cache stands at 100%.
I hadnt tried the v4 as I thought it was still beta (I usually like to use stable versions) but i will give it a shot!
P.S For your info Kraada we have solved the hud problem it was the Amount Won (Global) that was slowing the pop up menu..