[Koralatov]

I’ve upgraded my new MacBook Pro to 8GB of RAM, leaving me with two spare 2GB, PC3-10600 SO-DIMMS. My girlfriend’s MacBook Pro has 2GB of PC3-8500 RAM in it just now, and I’d hate to waste the 4GB I’ve got.

I know back in the Good Old Days, you could use PC-133 RAM in a PC-100 machine (I ran an iMac like that for a good few years without any problems). Is that still the case? Can I use the faster RAM in the old MacBook Pro without any ill effects?

[mduell]

Yes, as long as the SPD tables have the slower speeds defined in them.

It won't cause problems even if they don't, it just won't work. So it's worth a try.

[Koralatov]

Thanks for the quick reply, mduell. I’ll give it a go and report back.

[Koralatov]

Just to report back: it’s working perfectly so far. The RAM’s been in place for a couple of hours without any problems. I did notice that “About This Mac” reports it as 4GB of 1333MHz, so obviously it realises I’ve installed faster RAM, but there seems to have been no ill-effect.

[mduell]

Oh I forgot about the nVidia chipset era. MCP79MX does support 1333MT/s RAM, so it's running it at 1333MT/s.

[Koralatov]

Another update: almost a month of use with no problems.