Ultra Platinum.
PC4200 2x512 works with no memory errors with PAT and turbo on 540 MHz. No other memory comes even close for me.
PC4000 2x512 got only to 520 MHz but I am guessing chipset limitations.
PC4000 2x256 exactly the same case.
PC3500 2x256 works fine at 5:4 on 264 MHz FSB, turbo on with 2-3-3-6.
Top quality memory and not for AMD systems.
Funny, all of the above was bought refurbished, I guess some NForce guy was forcing it and then RMA'd.
All of the above passes 10 loops of MemTest86 and few hours of Prime95. With these experiences there is no way in hell I would use any other memory on Intel than GEIL. They have me.