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Arshad On Mon, Sep 8, 2008 at 1:50 PM, Dr A. Zaman <[log in to unmask]> wrote: > > Hi Darren, > > Many thanks for the quick response. > > I am at the model estimating stage using spm2, > even with 15 subjects (-albeit 444vols/subject), Well, Windows does not win the prize for memory management. > > I get the notorious memory error. Would a 64bit/8GB work for sure? Possibly. I didn't ask how big your images are, but no matter. If you have access to a Linux machine you might try the analysis there. That would give you a better idea on the likelihood of working. You can check the maxmem setting in spm_defaults. If it is more than 2^20 it is possible that lowering the value would load less data at a time and that might help. Using less than 2^20 is usually not helpful and will increase the run time enormously. (I've never found this makes much of a difference, but you can try it. Memory errors usually occur in relation to manipulating the large covariance matrices.) You can try turning off java in matlab - I think matlab -nojvm when you start matlab from a shortcut. You can check what other processes you have running and close all non-essential programs. > Also, if I > re-run the model estimation is SPM5, is it going > to be any easier (assuming I pre-process my data in SPM5)? No. Won't make a difference regarding memory issues. Darren > > best wishes, > > Arshad > > > > On Mon, 8 Sep 2008, Darren Gitelman wrote: > > Hi Arshad >> >> I don't think you will be able to do this with less than a 64 bit machine >> and 8 gb ram if you want to analyze them all together (i.e., a big fixed >> effects analysis). However, with 30 subjects I would think you would have >> sufficient numbers to perform a random effects analysis, in which case >> each >> subject could be analyzed separately and that should certainly work. >> >> regards, >> darren >> >> On Mon, Sep 8, 2008 at 11:43 AM, Dr A. Zaman <[log in to unmask]> >> wrote: >> >> Dear SPM experts, >>> >>> I was wondering if anyone can suggest approx. how much >>> RAM is needed in order to model fMRI data consisting >>> of 30 subjects, 8 conditions, 444 (3mm/isotropic) volumes? >>> I have used a pc with 4GB RAM with no joy, could not even run >>> half the number of subjects. Prior to getting hold of an 8GB >>> machine, can I cam sure that it will work? Any comments will be greatly >>> appreciated. >>> >>> Many thanks, >>> >>> Arshad >>> >>> >>> *********************************************************/ >>> >>> Dr. A Zaman, >>> Clinical Sciences Centre, >>> University Hospital Aintree, >>> Lower Lane, >>> Liverpool, UK. >>> L9 7AL. >>> >>> *********************************************************/ >>> >>> >> >> >> -- >> ----- >> Darren Gitelman >> >> -- ----- Darren Gitelman