64 vs 32. Any performance gain/loss?

I've read that 64bit os's and apps use more memory than their 32bit counterpart.

One reason I'm using Linode is that we can choose a 32 bit os. Granted, if I had 2 megs of RAM maybe it wouldn't make a difference.

But my question is, using the standard L360, has anyone noticed any performance differences with 32 vs 64? With the same OS, apps, etc?

In theory, wouldn't a 32 bit OS/apps be more efficient at lower memory levels than 64 bit?

Thanks.