Two new WHQL drivers were released today and are both at NVidia downloads. Both driver numbers are smaller than the most recent driver releases. The reason for this is a bit mysterious, the release highlights for both drivers say "This driver adds security updates for the driver components nvlddmkm.sys and nv4_mini.sys."
Heaven Benchmark with driver 345.20 installed: It's performance is right in line with drivers 349.65 and 347.52, when running on Windows 10 build 9926 with a GTX 980 and a i7 4770K cpu.