It is my understanding that it is probably okay, but that they both may run at just PC-100, just like if you mix cas-2 with cas-3, it will probably run both DIMMs at cas 3. In other words, if you want to maximize performance and minimize potential problems, run the same kind of ram together. Anything less may lead to less than optimal performance. I am running a 64 mb DIMM of mushkin budget PC-100 with a 64 mb DIMM of Crucial PC-100 at cas 3 and have no problems even with a Celeron 600 overclocked to 900 MHz. I might run even better if I put a PC-133 cas 2 Dimm in there to replace the two. And with the price of ram, it is darn tempting. Only my cheap nature (and my all too sensible wife) are holding me back. If Mushkin PC-133 drops below $65 for a 128 mb DIMM, not even the both of them combined will be able to stop me!!😀
Chuck