Unbalanced RAM sticks in T60/61

[SkiBunny]

Is there anything wasteful or bad about having two different-sized RAM sticks in a T60 or T61 (eg. one 2G and one 1G or 0.5G) ? Assuming both sticks are the same speed. I thought someone once wrote that both sticks should be the same size.

[tomh009]

Two identical modules will enable the system to use the memory in dual-channel mode, theoretically doubling the memory bandwidth. A pure memory bandwidth benchmark will show a big difference, but in practical terms most CPU-intensive benchmarks will show a gain of maybe 2-5% in a dual-channel configuration.

[SkiBunny]

Thanks, i thought it was something like that. But I dont understand the practical implications of having two different-sized DDR2 PC5300 sticks.

Most apps ppl use would tend to be I/O-bound or swapping memory, rather than CPU-bound (i think)

So what would be better?...
a) 2x512MB (identical size)
b) 1x1GB + 1x512MB (different sizes but more RAM)

[tomh009]

As you said, memory (availability) and I/O are the bottlenecks: more memory trumps any other improvement (with disk performance probably second). So I would suggest going for the 1.5 GB configuration, and I will be doing the same on my X61, using 1+2 GB modules for 3 GB total.

[SkiBunny]

Thanks! So I will just add someone's dirt-cheap throw-away 0.5gb to the 1gb on my t60 running XP
Whereas I guess adding 2GB to 1GB is the price you pay for vista, lol

Thanks!

[Harryc]

Just wanted to add using that (2) 'identical' modules to produce dual channel does not necessarily mean the manufacturers need to be the same. I have 1GB Elpida and 1GB Crucial in my T60 and it is definitely running dual channel.

[laowai]

I have a 1 and a 2g stick in mine. Unless they come up with a way to actually enable the full 4g, swapping the 1 for another 2 is too much of a waste. It works fine though

[jgrobertson]

Two identical modules will enable the system to use the memory in dual-channel mode, theoretically doubling the memory bandwidth. A pure memory bandwidth benchmark will show a big difference, but in practical terms most CPU-intensive benchmarks will show a gain of maybe 2-5% in a dual-channel configuration.

With a T60 which has the 3 GByte ram limit, would putting two 2 GByte sticks in give it dual channel? Right now I have a 1 and 2 for 3 total. I still have another 1 and could go back to 2 GByte total. Would that be better or is it better to have 3 GByte with unbalanced sizes.

[tomh009]

For most applications, 1+2 GB will likely provide better performance than 1+1 GB.