Update 2: Damn, those PC-2700R (DDR-333) modules going DDR-467... and even in dualchannel. Overcame that one module PC-3200R! That's crazy.
They have Micron chips. Maybe it is related with this article.. https://www.anandtech.com/show/1415/19
Micron chips according Anandtech performed very well on Athlon64 platform.

Anyway, that's crazy. 333@467 is 40% overclock from rated speed! (timings were CL3-3-3-8 2.7v , from original CL2.5-3-3-7 2.5v). Still didnt find the maximum, it's just they've passed the memtest.

I've tested speed difference between registered ECC memory module, and normal PC3200 module.
But only in memtestx86... there's "Memory" line below L1 cache-L3cache speeds.

at the same speed 233MHz(DDR467)...
For registered ECC memory , it was 1343 MB/s for single channel and 1959 MB/s for dual-channel. (ECC was disabled in BIOS)
For normal nonECC memory it was 1489 MB/s for single channel and 2015 MB/s for dual-channel.

timings were also same CL3-3-3-8

(note: PC-3200 (DDR400) speed at 200mhz HTT (so 1:1 divider) was 1280MB/s in single channel)
edit2: at 250Mhz(DDR500) registered ECC memory has only 1474MB/s in single channel, so still slower than nonECC classic memory at DDR466)