I had a Blizzard 1260 overclocked to 66mhz and the SCSI kit working without any problems at all. Just make sure you are running all the latest drivers. I used EDO simms without any trouble whatsoever. I could only use the simm on the scsi kit due to the fan blocking the use of the simm on the 1260 card... I used a 64mb EDO simm without any drama. It ran like a dream!