Photoshop: does 64 bit vs 32 bit matter?

Nik software is not compatible with CS5 unless it is set up to run in 32 bit mode instead of 64 bit mode.

Does that matter and if so what is affected by running 32 bit?

thanks,
Peter

Peter - Pretty much the only reason to go 64-bit is to allow PS to use a lot more RAM than it otherwise can. If you're only working on small files, and only running PS, you shouldn't see much difference. But if you work on larger files you can see a huge difference in performance, since PS will have to use the hard drive to swap data which is much, much slower than RAM. With 32-bit PS the effective RAM limit is a little under 3 GB. With 64-bit PS, the limit is something higher than I know - probably in the hundreds of GB's or more. (Technically, a 64-bit address could accomodate about a billion times more RAM than 32-bits, but the practical limit is the amount that can be connected and driven, so I don't know where that falls.)

Peter, David is right on with 32 vs 64 which is why I run everything I can in 64 bit mode. However, what's more interesting to me is that Nik is only 32 bit. I was about to look at their software but that cancels them out.

I would rephrase it to say that Nik is currently only 32 bit (except for Viveza, which IS available in 64-bit). They are actively working on 64 bit versions (per some of the Nik developers on another photography site). They have not done a good job of getting the 64 bit versions of things out in a timely fashion, though. This is the announcement from the Nik site FAQ :

Are Nik Software products compatible with 64-bit host application?


Currently, Viveza 2 for Windows is the only available 64-bit compatible application.

Nik Software is pleased to announce our commitment to developing native Windows and Macintosh 64-bit versions of our current plug-ins. We will make them available free of charge to registered customers who use Photoshop, Lightroom, or Apple Aperture 3. We are actively working to add 64-bit compatibility to the Macintosh version of Viveza 2 product and expect to be finished mid-year. Once the update for Viveza 2 is released, we will deliver cross-platform 64-bit versions of our remaining products as they become available. Registered customers will be notified of the availability of 64-bit versions by email, including instructions on how to access the updated versions.

To register your products if you have not already done so, please click here.

For information on how to access the 32-bit versions of our products until 64-bit compatibility is available, please click here.

Thanks David. I appreciate it.

If I am not mistaken, you can install PS64 and PS32 on your machine, simultaneously. That way, you can use your NIK pluggins by selecting PS32.

That's true Nathaniel, for Windows (in fact, the default for the program is to install both 32 and 64 bit versions). It's more difficult to switch between 64 and 32 bit apps on Macs.

Either way, though, it's much nicer not to have to switch, and the plug-ins can then see the benefit of 64-bits. Nik has actually updated their announcement on their site, and is close to releasing more 64-bit versions.