Hello,
I have been running PI on my very dated Dell M2400 Precision Worstation laptop. It is an old dual core, 2.5 Ghz, 32-bit machine.. it does run PI but slowly... and there are memory issues that I have worked around. I was waiting for the new Haswell chips to come out before buying a new machine. Ideally I could just buy a big cheap desktop, but like to move all my materials from home and office on a daily basis and work in a mobile secured environment so the laptop needs to be excrypted, VPNable etc. etc....
So, I am attracted by the sexy new SONY convertable ultrabooks, DELL makes similar ones, but they run the 4900U processor, up to 3 Ghz, but which has only 2 cores and 4 threads... but they are oh so light and have long battery life and will run Windows 8 on a tablet format.
To get the 4900MQ with 4 cores and 8 threads you need a standard (5-6lb) laptop from either Dell or HP. It runs up to 3.6 Ghz.
Both lines of computer are 64-bit, so that is a big step up from my current rig, but I guess the question is are people running PI on 64-bit dual processors OK, or do you really want a quad?
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Excuse me in advance as I will also post this over at CloudyNights...