From the data, max RAM is 3 GB. i'd say PC2-5300 667 MHz. Couple of things: the sockets have to match and they have to have similar power consumption. You have the 479 socket (Socket M), and there are faster Core 2 Duos that fit into it. I'd say that you could put any Merom architecture socket M, 34 watt 667 MHz FSB Core 2 Duo in it. The fastest one is the C2D T7600 2.3 GHz if I remember correctly. It's 34 watts, 667 MHz FSB, same footprint and power consumption, same architecture. Should be compatible. It's tons faster than the T5500 you have. The only limiter would be your chipset. These CPU's generally went into the 945G/M chipset. Your data didn't say what it had. You would be better off doing a CPUID analysis. Go look up CPUz on Google and look for CPU-ID. Run that and post your results.